Edward Sargent

In electrochemical CO2 reduction (CO2R) into chemicals and fuels, it is a long-standing challenge to suppress the competing hydrogen evolution reaction (HER) and steer selectivity to a single valuable product. Ethylene is a desired model molecule in light of its large market size, range of applications from polymers to sustainable aviation fuel, and large present-day carbon intensity. The reaction pathways and reactivity of CO2R rely on catalyst surface properties and local reaction environments. Here we review the mechanistic understanding of CO2R to ethylene; we then discuss catalyst design strategies in light of the link between catalyst structure, reaction pathways, and ethylene production performance. We close with challenges in catalyst design and provide an outlook for further research directions to accelerate the rational design of catalysts.

Perovskite solar cells (PSCs) in the pin structure are limited by nonradiative recombination at the electron transport layer (ETL) interface, which is exacerbated in narrow-bandgap (∼1.2 eV) Pb–Sn PSCs due to surface Sn oxidation and detrimental p-doping. Photoluminescence quantum yield studies herein indicated that ethane-1,2-diammonium (EDA) passivation only partially alleviates perovskite/ETL energetic losses. We pursued passivation of the defect-rich perovskite:ETL interface to reduce nonradiative losses; our target was to combine chemical coordination of Sn sites with the introduction of an interlayer, which we implemented by introducing long-chain carboxylic acid ligands at the perovskite surface. Treatment with oleic acid (OA) led to reduced recombination at the perovskite/ETL interface and evidence of Sn2+ coordination. This reduced the VOC deficit of Pb–Sn PSCs to 0.34 V, resulting in a 0.89 V V …

Hydrogenation of biomass‐derived chemicals is of interest for the production of biofuels and valorized chemicals. Thermochemical processes for biomass reduction typically employ hydrogen as the reductant at elevated temperatures and pressures. Here we investigate direct electrified reduction of 5‐Hydroxymethylfurfural (HMF) to a precursor to bio‐polymers, 2,5‐bis(hydroxymethyl)furan (BHMF). Noting a limited current density in prior reports of this transformation, we investigated the use of a hybrid catalyst consisting of ternary metal nanodendrites mixed with a cationic ionomer, the latter purposed to increase local pH and facilitate surface proton diffusion. We found that the approach, when implemented using Ga‐doped Ag‐Cu electrocatalysts designed for p‐d orbital hybridization, steered selectivity to BHMF, achieving a faradaic efficiency of 58% at 100 mA/cm2 and a production rate of 1 mmol/cm2/h, this latter …

Polar crystalline materials, a subset of the non‐centrosymmetric materials, are highly sought after. Their symmetry properties make them pyroelectric and also piezoelectric and capable of second‐harmonic generation (SHG). For SHG and piezoelectric applications, metal oxides are commonly used. The advantages of oxides are durability and hardness – downsides are the need for high‐temperature synthesis/processing and often the need to include toxic metals. Organic polar crystals, on the other hand, can avoid toxic metals and can be amenable to solution‐state processing. While the vast majority of polar organic molecules crystallize in non‐polar space groups, we found that both 7‐chloro‐1,3,5‐triazaadamantane, for short Cl‐TAA, and also the related Br‐TAA (but not I‐TAA) form polar crystals in the space group R3m, easily obtained from dichloromethane solution. Measurements confirm piezoelectric and …

CO2 electrolyzers have progressed rapidly in energy efficiency and catalyst selectivity toward valuable chemical feedstocks and fuels, such as syngas, ethylene, ethanol, and methane. However, each component within these complex systems influences the overall performance, and the further advances needed to realize commercialization will require an approach that considers the whole process, with the electrochemical cell at the center. Beyond the cell boundaries, the electrolyzer must integrate with upstream CO2 feeds and downstream separation processes in a way that minimizes overall product energy intensity and presents viable use cases. Here we begin by describing upstream CO2 sources, their energy intensities, and impurities. We then focus on the cell, the most common CO2 electrolyzer system architectures, and each component within these systems. We evaluate the energy savings and the …

Biomass incorporates carbon captured from the atmosphere and can serve as a renewable feedstock for producing valuable chemicals and fuels. Here we look at how electrochemical approaches can impact biomass valorization, focusing on identifying chemical transformations that leverage renewable electricity and feedstocks to produce valorized products via electro-privileged transformations. First, we recommend that the field should explore widening the spectrum of platform chemicals derived from bio-feedstocks, thus offering pathways to molecules that have historically been derived from petroleum. Second, we identify opportunities in electrocatalytic production of energy-dense fuels from biomass that utilize water as the hydrogen source and renewable electricity as the driving force. Finally, we look at the potential in electrochemical depolymerization to preserve key functional groups in raw feedstocks that …

Compressive strain engineering improves perovskite stability. Two-dimensional compressive strain along the in-plane direction can be applied to perovskites through the substrate; however, this in-plane strain results in an offsetting tensile strain perpendicular to the substrate, linked to the positive Poisson ratio of perovskites. Substrate-induced strain engineering has not yet resulted in state-of-the-art operational stability. Here, we seek instead to implement hydrostatic strain in perovskites by embedding lattice-mismatched perovskite quantum dots (QDs) into a perovskite matrix. QD-in-matrix perovskites show a homogeneously strained lattice as evidenced by grazing-incidence X-ray diffraction. We fabricate mixed-halide wide-band-gap (Eg; 1.77 eV) QD-in-matrix perovskite solar cells that maintain >90% of their initial power conversion efficiency (PCE) after 200 h of one-sun operation at the maximum power point …

Electrosynthesis of acetate from CO offers the prospect of a low-carbon-intensity route to this valuable chemical––but only once sufficient selectivity, reaction rate and stability are realized. It is a high priority to achieve the protonation of the relevant intermediates in a controlled fashion, and to achieve this while suppressing the competing hydrogen evolution reaction (HER) and while steering multicarbon (C2+) products to a single valuable product––an example of which is acetate. Here we report interface engineering to achieve solid/liquid/gas triple-phase interface regulation, and we find that it leads to site-selective protonation of intermediates and the preferential stabilization of the ketene intermediates: this, we find, leads to improved selectivity and energy efficiency toward acetate. Once we further tune the catalyst composition and also optimize for interfacial water management, we achieve a cadmium-copper …

Heavy‐metal‐free III–V colloidal quantum dots (CQDs) are promising materials for solution‐processed short‐wave infrared (SWIR) photodetectors. Recent progress in the synthesis of indium antimonide (InSb) CQDs with sizes smaller than the Bohr exciton radius enables quantum‐size effect tuning of the band gap. However, it has been challenging to achieve uniform InSb CQDs with band gaps below 0.9 eV, as well as to control the surface chemistry of these large‐diameter CQDs. This has, to date, limited the development of InSb CQD photodetectors that are sensitive to 1400 nm light. Here we adopt solvent engineering to facilitate a diffusion‐limited growth regime, leading to uniform CQDs with a band gap of 0.89 eV. We then develop a CQD surface reconstruction strategy that employs a dicarboxylic acid to selectively remove the native In/Sb oxides, and enables a carboxylate‐halide co‐passivation with the …

Surface defects in semiconducting materials, though they have been widely studied, remain a prominent source of loss in optoelectronic devices; here we sought a new angle of approach, looking into the dynamic roles played by surface defects under atmospheric stressors and their chemical passivants in the lifetime of optoelectronic materials. We find that surface defects possess properties distinct from those of bulk defects. ab initio molecular dynamics simulations reveal a previously overlooked reversible degradation mechanism mediated by hydrogen vacancies. We find that dynamic surface adsorption affinity (DAA) relative to surface treatment ligands is a surrogate for passivation efficacy, a more strongly-correlated feature than is the static binding strength emphasized in prior reports. This guides us to design targeted passivator ligands with high molecular polarity: for example, 4-aminobutylphosphonic acid …

The present disclosure relates to an electrode for CO 2 electroreduction in an acidic electrolyte comprising cation species, the electrode comprising: a substrate, a metal-based catalyst material, and a cation-augmenting material; wherein the cation-augmenting material comprises an acidic group exchanging protons with the cation species of the acidic electrolyte so as to increase a concentration of the cation species at a surface of the electrode.

High-performance catalysts are crucial for sustainable energy conversion and human health. However, the discovery of catalysts faces challenges due to the absence of efficient approaches to navigating vast and high-dimensional structure and composition spaces. In this study, we propose a high-throughput computational catalyst screening approach integrating density functional theory (DFT) and Bayesian Optimization (BO). Within the BO framework, we propose an uncertainty-aware atomistic machine learning model, UPNet, which enables automated representation learning directly from high-dimensional catalyst structures and achieves principled uncertainty quantification. Utilizing a constrained expected improvement acquisition function, our BO framework simultaneously considers multiple evaluation criteria. Using the proposed methods, we explore catalyst discovery for the CO2 reduction reaction. The results demonstrate that our approach achieves high prediction accuracy, facilitates interpretable feature extraction, and enables multicriteria design optimization, leading to significant reduction of computing power and time (10x reduction of required DFT calculations) in high-performance catalyst discovery.

Electrochemical direct air capture (DAC) can leverage renewable electricity to reduce atmospheric CO2 levels via energy-efficient organic redox couples. However, current organic systems are threatened by oxidative degradation when explosed to air. In this work, we propose an electrochemical process to regenerate hydroxide absorbents via cyclic viologen electrocatalysis (CVE). This strategy isolates the redox-active viologens from the alkaline absorbents to avoid oxidative degradation and vaporization loss. Tuning the viologen substituent is needed to facilitate fast reaction kinetics in the electric fields present under reductive and oxidative environments. We show that di-polar viologens, which contain both positively and negatively charged groups, can overcome electric field repulsion during reduction and oxidation. We demonstrate a minimum work of 0.82 GJ per tCO2, calculated based on the cyclic …

Perovskite solar cells have seen impressive progress in performance and stability, yet maintaining efficiency while scaling area remains a challenge. Here we find that additives commonly used to passivate large-area perovskite films often co-precipitate during perovskite crystallization and aggregate at interfaces, contributing to defects and to spatial inhomogeneity. We develop design criteria for additives to prevent their evaporative precipitation and enable uniform passivation of defects. We explored liquid crystals with melting point below the perovskite processing temperature, functionalization for defect passivation and hydrophobicity to improve device stability. We find that thermotropic liquid crystals such as 3,4,5-trifluoro-4′-(trans-4-propylcyclohexyl)biphenyl enable large-area perovskite films that are uniform, low in defects and stable against environmental stress factors. We demonstrate modules with a …

Perovskite light-emitting diodes (PeLEDs) have garnered worldwide attention as a promising technology for the next generation of display devices. Although initial reports focused on laboratory-scale spin-coating techniques, rapid advances have prompted researchers to explore pathways for their scaled manufacture. Drawing inspiration from the success of organic LEDs, the community has begun to look at vapour deposition to build reliable PeLED displays. This Perspective article examines the development of vapour-deposited PeLEDs, particularly emphasizing the underlying factors that limit their performance compared with their solution-processed counterparts. We offer routes to improve device performance, including optimizing film quality and engineering device architecture, and summarize potential applications for vapour-deposited PeLEDs. Finally, we outline development opportunities in this evolving field.

The identification of genetic regulators of cell secretions is challenging because it requires the sorting of a large number of cells according to their secretion patterns. Here we report the development and applicability of a high-throughput microfluidic method for the analysis of the secretion levels of large populations of immune cells. The method is linked with a kinome-wide loss-of-function CRISPR screen, immunomagnetically sorting the cells according to their secretion levels, and the sequencing of their genomes to identify key genetic modifiers of cell secretion. We used the method, which we validated against flow cytometry for cytokines secreted from primary mouse CD4+ (cluster of differentiation 4-positive) T cells, to discover a subgroup of highly co-expressed kinase-coding genes that regulate interferon-gamma secretion by these cells. We validated the function of the kinases identified using RNA interference …

Quantum information processing—which relies on spin defects or single-photon emission—has shown quantum advantage in proof-of-principle experiments including microscopic imaging of electromagnetic fields, strain and temperature in applications ranging from battery research to neuroscience. However, critical gaps remain on the path to wider applications, including a need for improved functionalization, deterministic placement, size homogeneity and greater programmability of multifunctional properties. Colloidal semiconductor nanocrystals can close these gaps in numerous application areas, following years of rapid advances in synthesis and functionalization. In this Review, we specifically focus on three key topics: optical interfaces to long-lived spin states, deterministic placement and delivery for sensing beyond the standard quantum limit, and extensions to multifunctional colloidal quantum circuits.

Inverted (pin) perovskite solar cells (PSCs) afford improved operating stability in comparison to their nip counterparts but have lagged in power conversion efficiency (PCE). The energetic losses responsible for this PCE deficit in pin PSCs occur primarily at the interfaces between the perovskite and the charge-transport layers. Additive and surface treatments that use passivating ligands usually bind to a single active binding site: This dense packing of electrically resistive passivants perpendicular to the surface may limit the fill factor in pin PSCs. We identified ligands that bind two neighboring lead(II) ion (Pb2+) defect sites in a planar ligand orientation on the perovskite. We fabricated pin PSCs and report a certified quasi–steady state PCE of 26.15 and 24.74% for 0.05– and 1.04–square centimeter illuminated areas, respectively. The devices retain 95% of their initial PCE after 1200 hours of continuous 1 sun …

III‐V colloidal quantum dots (CQDs) are of interest in infrared photodetection, and recent developments in CQDs synthesis and surface engineering have improved performance. Here this work investigates photodetector stability, finding that the diffusion of zinc ions from charge transport layers (CTLs) into the CQDs active layer increases trap density therein, leading to rapid and irreversible performance loss during operation. In an effort to prevent this, this work introduces organic blocking layers between the CQDs and ZnO layers; but these negatively impact device performance. The device is then, allowing to use a C60:BCP as top electron‐transport layer (ETL) for good morphology and process compatibility, and selecting NiOX as the bottom hole‐transport layer (HTL). The first round of NiOX‐based devices show efficient light response but suffer from high leakage current and a low open‐circuit voltage (Voc) due …

Perovskite/perovskite/silicon triple-junction solar cells hold promise for surpassing their two-junction counterparts in performance. Achieving this requires monolithic integration of a ∼2.0 eV band-gap perovskite subcell, characterized by a high bromide:iodide ratio (>7:3), and with low-temperature processability and high optoelectronic quality. However, light-induced phase segregation in such perovskites remains a challenge. To address this, we propose modifying the wide-band-gap perovskite with potassium thiocyanate (KSCN) and methylammonium iodide (MAI) co-additives, where SCN− increases the perovskite grain size, reducing the grain boundary defect density; K+ immobilizes the halide, preventing the formation of halide vacancies; and MA+ eliminates the residual light-destabilizing SCN− in the perovskite films via double displacement reactions. Our co-additive strategy enables enhanced photostability …

The disclosure discloses a membrane electrode assembly (MEA) for electrochemically converting carbon monoxide (CO) into ethylene (C 2 H 4) under applied current density, the MEA comprising: a cathode; an anode; an anion-exchange membrane (AEM) to separate the cathode from the anode; an anolyte; a reactant inlet in fluid communication with the cathode to provide a CO-enriched gas component; and a product outlet in fluid communication with the cathode to release a product mixture comprising C 2 H 4; wherein the cathode comprises: a first layer including adsorption sites to adsorb CO as CO* intermediates; a second layer that facilitates stabilization of the CO* intermediates for adsorption onto the adsorption sites of the first layer; and a third layer that facilitates diffusion of CO to the adsorption sites of the first layer.

The electrochemical reduction of CO2 in acidic conditions enables high single-pass carbon efficiency. However, the competing hydrogen evolution reaction reduces selectivity in the electrochemical reduction of CO2, a reaction in which the formation of CO, and its ensuing coupling, are each essential to achieving multicarbon (C2+) product formation. These two reactions rely on distinct catalyst properties that are difficult to achieve in a single catalyst. Here we report decoupling the CO2-to-C2+ reaction into two steps, CO2-to-CO and CO-to-C2+, by deploying two distinct catalyst layers operating in tandem to achieve the desired transformation. The first catalyst, atomically dispersed cobalt phthalocyanine, reduces CO2 to CO with high selectivity. This process increases local CO availability to enhance the C–C coupling step implemented on the second catalyst layer, which is a Cu nanocatalyst with a Cu–ionomer …

Renewable-energy-powered electrosynthesis has the potential to contribute to decarbonizing the production of propylene glycol, a chemical that is used currently in the manufacture of polyesters and antifreeze and has a high carbon intensity. Unfortunately, to date, the electrooxidation of propylene under ambient conditions has suffered from a wide product distribution, leading to a low faradic efficiency toward the desired propylene glycol. We undertook mechanistic investigations and found that the reconstruction of Pd to PdO occurs, followed by hydroxide formation under anodic bias. The formation of this metastable hydroxide layer arrests the progressive dissolution of Pd in a locally acidic environment, increases the activity, and steers the reaction pathway toward propylene glycol. Rh-doped Pd further improves propylene glycol selectivity. Density functional theory (DFT) suggests that the Rh dopant lowers the …

Quantum dot (QD) light‐emitting diodes (QLEDs) are promising for next‐generation displays, but suffer from carrier imbalance arising from lower hole injection compared to electron injection. A defect engineering strategy is reported to tackle transport limitations in nickel oxide‐based inorganic hole‐injection layers (HILs) and find that hole injection is able to enhance in high‐performance InP QLEDs using the newly designed material. Through optoelectronic simulations, how the electronic properties of NiOx affect hole injection efficiency into an InP QD layer, finding that efficient hole injection depends on lowering the hole injection barrier and enhancing the acceptor density of NiOx is explored. Li doping and oxygen enriching are identified as effective strategies to control intrinsic and extrinsic defects in NiOx, thereby increasing acceptor density, as evidenced by density functional theory calculations and …

Monolithic all-perovskite triple-junction solar cells have the potential to deliver power conversion efficiencies beyond those of state-of-art double-junction tandems and well beyond the detailed-balance limit for single junctions. Today, however, their performance is limited by large deficits in open-circuit voltage and unfulfilled potential in both short-circuit current density and fill factor in the wide-bandgap perovskite sub cell. Here we find that halide heterogeneity—present even immediately following materials synthesis—plays a key role in interfacial non-radiative recombination and collection efficiency losses under prolonged illumination for Br-rich perovskites. We find that a diammonium halide salt, propane-1,3-diammonium iodide, introduced during film fabrication, improves halide homogenization in Br-rich perovskites, leading to enhanced operating stability and a record open-circuit voltage of 1.44 V in an …

The external quantum efficiency of state-of-the-art quantum dot light-emitting diodes is limited by the low photon out-coupling efficiency. Light-emitting diodes using oriented nanostructures such as nanorods, nanoplatelets and dot-in-disc nanocrystals favour photon out-coupling; however, their internal quantum efficiency is often compromised and thus achieving a net gain has proved challenging. Here we report isotropic-shaped quantum dots featuring a mixed-crystallographic structure composed of wurtzite and zinc blende phases. The wurtzite phase promotes dipole–dipole interactions that orient quantum dots in solution-processed films, whereas the zinc blende phase helps lift the electronic state degeneracy to enable directional light emission. These combined features improve photon out-coupling without compromising internal quantum efficiency. Fabricated light-emitting diodes exhibit an external quantum …

Molecular hole-transporting materials (HTMs) having triphenylethylene central core were designed, synthesized, and employed in perovskite solar cell (PSC) devices. The synthesized HTM derivatives were obtained in a two- or three-step synthetic procedure, and their characteristics were analyzed by various thermoanalytical, optical, photophysical, and photovoltaic techniques. The most efficient PSC device recorded a 23.43% power conversion efficiency. Furthermore, the longevity of the device employing V1509 HTM surpassed that of PSC with state-of-art spiro-OMeTAD as the reference HTM.

The fabrication of perovskite solar cells (PSCs) through blade coating is seen as one of the most viable paths toward commercialization. However, relative to the less scalable spin coating method, the blade coating process often results in more defective perovskite films with lower grain uniformity. Ion migration, facilitated by those elevated defect levels, is one of the main triggers of phase segregation and device instability. Here, a bifunctional molecule, p‐aminobenzoic acid (PABA), which enhances the barrier to ion migration, induces grain growth along the (100) facet, and promotes the formation of homogeneous perovskite films with fewer defects, is reported. As a result, PSCs with PABA achieved impressive power conversion efficiencies (PCEs) of 23.32% and 22.23% for devices with active areas of 0.1 cm2 and 1 cm2, respectively. Furthermore, these devices maintain 93.8% of their initial efficiencies after 1 000 …

A self-cleaning CO 2 reduction strategy is proposed herein including alternating operation and regeneration of the CO 2 electrolysis system. The strategy includes application of short and periodic reductions in applied voltage, thereby avoiding saturation and prevention of carbonate salt formation.

Improving the kinetics and selectivity of CO2/CO electroreduction to valuable multi-carbon products is a challenge for science and is a requirement for practical relevance. Here we develop a thiol-modified surface ligand strategy that promotes electrochemical CO-to-acetate. We explore a picture wherein nucleophilic interaction between the lone pairs of sulfur and the empty orbitals of reaction intermediates contributes to making the acetate pathway more energetically accessible. Density functional theory calculations and Raman spectroscopy suggest a mechanism where the nucleophilic interaction increases the sp2 hybridization of CO(ad), facilitating the rate-determining step, CO* to (CHO)*. We find that the ligands stabilize the (HOOC–CH2)* intermediate, a key intermediate in the acetate pathway. In-situ Raman spectroscopy shows shifts in C–O, Cu–C, and C–S vibrational frequencies that agree with a picture of …

Perovskite solar cells (PSCs) consisting of interfacial two- and three-dimensional heterostructures that incorporate ammonium ligand intercalation have enabled rapid progress toward the goal of uniting performance with stability. However, as the field continues to seek ever-higher durability, additional tools that avoid progressive ligand intercalation are needed to minimize degradation at high temperatures. We used ammonium ligands that are nonreactive with the bulk of perovskites and investigated a library that varies ligand molecular structure systematically. We found that fluorinated aniliniums offer interfacial passivation and simultaneously minimize reactivity with perovskites. Using this approach, we report a certified quasi–steady-state power-conversion efficiency of 24.09% for inverted-structure PSCs. In an encapsulated device operating at 85°C and 50% relative humidity, we document a 1560-hour T85 at …

An electrochemical process, and related method and system to upgrade captured CO 2 into value-added products. CO 2 capture technologies based on chemisorption present the potential to lower net emissions of CO 2 into the atmosphere. The use of alkali cations to tailor the electrochemical double layer allows achieving the valorization of chemisorbed CO 2 in an aqueous amine-based electrolyte, by placing the CO 2 of the amine-CO 2 adduct sufficiently close to the site of an heterogeneous reaction at the working electrode. It is revealed, using electrochemical studies and in-situ surface-enhanced Raman spectroscopy, that a smaller double layer distance can correlate with improved activity for CO 2 to CO from amine solutions.

The capture and electrochemical conversion of CO2, powered by renewable electricity, is an attractive method of sustainably producing valuable chemicals and fuels (e.g. carbon monoxide (CO)), reducing atmospheric CO2, and storing intermittent renewable energy. Integrated capture and conversion (reactive capture) of CO2 presents a CO2-to-CO electrolysis pathway that eliminates most of the upstream capital and energy costs by releasing CO2 directly inside the electrolyzer using an internal pH-swing. The reactive capture system readily allows for the collection of produced gas products via phase separation, thus minimizing downstream separation costs.Industrial-scale integration of reactive capture systems with upgrading processes require a pure and consistent product stream. Previous studies using bicarbonate electrolytes have demonstrated high selectivity towards CO. However, the limited CO2 …

Pretreatment conditions dramatically alter the active surface of catalytic materials, influencing their performance. In a recent study, Monai et al. investigated the structural evolution of nickel nanoparticles (Ni NPs) supported on the reducible oxide TiO2 during the CO2 hydrogenation reaction. Operando electron microscopy showed the formation of TiOx bilayers during reductive pretreatments at 400°C, while thicker TiOx overlayers were generated during more aggressive pretreatment at 600°C. Under CO2 hydrogenation conditions, the TiOx bilayers receded, but small TiOx domains remained on the Ni/TiO2 materials that underwent pretreatment at 600°C. The partially intact TiOx overlayer led to an extensive interface between Ni and TiOx, improving catalytic activity and selectivity toward C2+ products that are particularly desired in CO2 utilization schemes.

The clinical use of tumour-infiltrating lymphocytes for the treatment of solid tumours is hindered by the need to obtain large and fresh tumour fractions, which is often not feasible in patients with unresectable tumours or recurrent metastases. Here we show that circulating tumour-reactive lymphocytes (cTRLs) can be isolated from peripheral blood at high yield and purity via microfluidic immunomagnetic cell sorting, allowing for comprehensive downstream analyses of these rare cells. We observed that CD103 is strongly expressed by the isolated cTRLs, and that in mice with subcutaneous tumours, tumour-infiltrating lymphocytes isolated from the tumours and rapidly expanded CD8+CD103+ cTRLs isolated from blood are comparably potent and respond similarly to immune checkpoint blockade. We also show that CD8+CD103+ cTRLs isolated from the peripheral blood of patients and co-cultured with tumour cells …

The nitrogen cycle needed for scaled agriculture relies on energy- and carbon-intensive processes and generates nitrate-containing wastewater. Here we focus on an alternative approach—the electrified co-electrolysis of nitrate and CO2 to synthesize urea. When this is applied to industrial wastewater or agricultural runoff, the approach has the potential to enable low-carbon-intensity urea production while simultaneously providing wastewater denitrification. We report a strategy that increases selectivity to urea using a hybrid catalyst: two classes of site independently stabilize the key intermediates needed in urea formation, *CO2NO2 and *COOHNH2, via a relay catalysis mechanism. A Faradaic efficiency of 75% at wastewater-level nitrate concentrations (1,000 ppm NO3− [N]) is achieved on Zn/Cu catalysts. The resultant catalysts show a urea production rate of 16 µmol h−1 cm−2. Life-cycle assessment …

Blue perovskite light-emitting diodes (LEDs) have shown external quantum efficiencies (EQEs) of more than 10%; however, devices that emit in the true blue—those that accord with the emission wavelength required for Rec. 2100 primary blue—have so far been limited to EQEs of ~6%. We focused here on true blue emitting CsPbBr3 colloidal nanocrystals (c-NCs), finding in early studies that they suffer from a high charge injection barrier, a problem exacerbated in films containing multiple layers of nanocrystals. We introduce a self-assembled monolayer (SAM) active layer that improves charge injection. We identified a bifunctional capping ligand that simultaneously enables the self-assembly of CsPbBr3 c-NCs while passivating surface traps. We report, as a result, SAM-based LEDs exhibit a champion EQE of ~12% [CIE of (0.132, 0.069) at 4.0 V with a luminance of 11 cd/m2], and 10-fold–enhanced operating …

The electrochemical CO2 reduction reaction (CO2RR) has progressed but suffers an energy penalty from CO2 loss due to carbonate formation and crossover. Cascade CO2 to CO conversion followed by CO reduction addresses this issue, but the combined figures of carbon efficiency (CE), energy efficiency (EE), selectivity, and stability require improvement. We posited that increased CO availability near active catalytic sites could maintain selectivity even under CO-depleted conditions. Here, we present a heterojunction carbon reservoir catalyst (CRC) architecture that combines copper nanoparticles with porous carbon nanoparticles. The pyridinic and pyrrolic functionalities of CRC can absorb CO enabling high CE under CO-depleted conditions. With CRC catalyst, we achieve ethanol FE and CE of 50% and 93% (CE∗Faradaic efficiency [FE] = 47%) in flow cell at 200 mA cm−2, fully doubling the best prior CE∗FE …

Carbon dioxide (CO2) electrolysis powered with renewable electricity can help close the carbon cycle by converting emissions into chemicals and fuels. Two key advancements are required to bridge the technological gaps for industrial implementation: pilot plant demonstrations with detailed performance data; and chemical engineering process models built and tested with lab- and pilot-scale data. Here, we develop a semi-empirical electrolyzer model in Aspen Custom Modeler which is trained on a 5 cm2 lab-scale CO2 electrolyzer. We then scale to a pilot-scale 800 cm2 single cell and 10 × 800 cm2 stack and use the results to validate the model; at 100 mA cm–2, the model can predict six of seven cell performance metrics within 16% absolute error and three of five stack metrics within 11% absolute error. With the combination of the electrolyzer model and the pilot-scale data, this work provides the prerequisites …

Balancing kinetics, a crucial priority in catalysis, is frequently achieved by sacrificing activity of elementary steps to suppress side reactions and enhance catalyst stability. Dry reforming of methane (DRM), a process operated at high temperature, usually involves fast C-H activation but sluggish carbon removal, resulting in coke deposition and catalyst deactivation. Studies focused solely on catalyst innovation are insufficient in addressing coke formation efficiently. Herein, we develop coke-free catalysts that balance kinetics of elementary steps for overall thermodynamics optimization. Beginning from a highly active cobalt aluminum oxide (CoAl2O4) catalyst that is susceptible to severe coke formation, we substitute aluminum (Al) with gallium (Ga), reporting a CoAl0.5Ga1.5O4-R catalyst that performs DRM stably over 1000 hours without observable coke deposition. We find that Ga enhances DRM stability by …

Two-dimensional (2D) hybrid perovskites harness the chemical and structural versatility of organic compounds. Here, we explore 2D perovskites that incorporate both a first organic component, a primary ammonium cation, and a second neutral organic module. Through the experimental examination of 42 organic pairs with a range of functional groups and organic backbones, we identify five crystallization scenarios that occur upon mixing. Only one leads to the cointercalation of the organic modules with distinct and extended interlayer spacing, which is observed with the aid of X-ray diffraction (XRD) pattern analysis combined with cross-sectional transmission electron microscopy (TEM) and elemental analysis. We present a picture in which complementary pairs, capable of forming intermolecular bonds, cocrystallize with multiple structural arrangements. These arrangements are a function of the ratio of organic …

The hybrid perovskite family characterized by exciting optoelectronic properties and chemical/physical versatilities holds potential for photonic applications. In addition to materials, the micro-/nanoarchitectures are critical to photonic-related properties (reflection/scattering/trapping/extraction/resonance/modulation) and spatially patterned arrays by photon-matter-structure interactions. The abundant processing strategies—covering in situ crystallization, the pre-synthesized nanocrystals (NCs), and vapor deposition—evolve kaleidoscopic perovskite architectures and photonic properties resulting from extensive experimental and theoretical efforts in various fields. Here, we review the perovskite micro-/nanoarchitectures with regard to photonic applications. We start with the perovskite materials, structure, and related optical dimensions, then systematically illustrate the top-down and bottom-up micro-/nanopatterning …

Operating stability has become a priority issue for all-perovskite tandem solar cells. Inorganic CsPbI3−xBrx perovskites, which have good photostability against halide segregation, are promising alternatives for all-perovskite tandem solar cells. However, the interface between organic transport layers and inorganic perovskite suffers from a large energetic mismatch and inhibits charge extraction compared with hybrid analogues, resulting in low open-circuit voltages and fill factors. Here we show that inserting at this interface a passivating dipole layer having high molecular polarity—a molecule that interacts strongly with both inorganic perovskite and C60—reduces the energetic mismatch and accelerates the charge extraction. This strategy resulted in a power conversion efficiency (PCE) of 18.5% in wide-bandgap (WBG) devices. We report all-perovskite tandems using an inorganic WBG subcell, achieving a PCE of …

Electrosynthesis of oxirane can include contacting a halide electrolyte with an anode that includes an electrocatalyst comprising iridium oxide loaded with a period-6 metal oxide and provided on a metal substrate. The cathode can be operated under ORR conditions. The electrochemical system can also be provided as an integrated system that includes CO 2 electroreduction to produce ethylene and formation of hypochlorous acid using the electrocatalyst, followed by contact of the ethylene and the hypochlorous acid to form ethylene chlorohydrin which is, in turn, contacted with OH− ions to produce oxirane.

Acidic conditions can enable high single-pass conversion in electrochemical CO2 reduction (CO2R) reaction. However, the kinetically facile hydrogen evolution reaction (HER) prevails in acidic conditions and limits the energy efficiency for CO2R towards multi-carbon (C2+) products. By performing electrodeposition under CO2R conditions, we synthesized a copper catalyst (EC-Cu) that promotes selective CO2R to C2+ products in acidic conditions. We combine in situ spectroscopy, DFT calculations, and catalyst performance to show that co-adsorbed CO and OH on the catalyst surface promote C-C coupling, which we correlate with evidence of increased CO residence time. With optimization, the EC-Cu catalyst achieved a 60% faradaic efficiency for ethylene and 90% for C2+. Furthermore, when implemented in a slim flow cell, the EC-Cu catalyst can attain a 20% energy efficiency toward ethylene production.

The electrochemical conversion of CO2 to multi-carbon products (C2+), such as ethylene and ethanol, is an attractive technology towards achieving net zero carbon emission goals. Among the available configurations of CO2 electrolysers, those employing a bipolar membrane (BPM) in forward-bias mode (f-BPM) reduce CO2 loss to the anode – a problem commonly faced in traditional anion exchange membrane (AEM) electrolysers. Therefore, carbon efficiency (the percent of input CO2 that is converted to C2+ products) and system operational costs can be improved.In f-BPM electrolysers, (bi)carbonate ions move through the AEM then combine with protons moving through the cation exchange membrane (CEM) to regenerate CO2 and H2O at the AEM|CEM interface. Recent reports have implemented a porous AEM structure or an added AEM|CEM interface channel to aid the movement of CO2 from the AEM …

Publisher Correction: Regulating surface potential maximizes voltage in all-perovskite tandems Publisher Correction: Regulating surface potential maximizes voltage in all-perovskite tandems Nature. 2023 Aug;620(7973):E15. doi: 10.1038/s41586-023-06450-5. Authors Hao Chen # 1 , Aidan Maxwell # 1 , Chongwen Li # 1 2 , Sam Teale # 1 , Bin Chen # 1 3 , Tong Zhu 1 , Esma Ugur 4 , George Harrison 4 , Luke Grater 1 , Junke Wang 1 , Zaiwei Wang 1 , Lewei Zeng 1 , So Min Park 1 , Lei Chen 2 , Peter Serles 5 , Rasha Abbas Awni 2 , Biwas Subedi 2 , Xiaopeng Zheng 6 , Chuanxiao Xiao 6 , Nikolas J Podraza 2 , Tobin Filleter 5 , Cheng Liu 3 7 , Yi Yang 3 7 , Joseph M Luther 6 , Stefaan De Wolf 4 , Mercouri G Kanatzidis 3 , Yanfa Yan 8 , Edward H Sargent 9 10 11 Affiliations 1 The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada. 2 Department of …

The open-circuit voltage (VOC) deficit in perovskite solar cells is greater in wide-bandgap (over 1.7 eV) cells than in perovskites of roughly 1.5 eV (refs. ,). Quasi-Fermi-level-splitting measurements show VOC-limiting recombination at the electron-transport-layer contact, –. This, we find, stems from inhomogeneous surface potential and poor perovskite–electron transport layer energetic alignment. Common monoammonium surface treatments fail to address this; as an alternative, we introduce diammonium molecules to modify perovskite surface states and achieve a more uniform spatial distribution of surface potential. Using 1,3-propane diammonium, quasi-Fermi-level splitting increases by 90 meV, enabling 1.79 eV perovskite solar cells with a certified 1.33 V VOC and over 19% power conversion efficiency (PCE). Incorporating this layer into a monolithic all-perovskite tandem, we report a record VOC of 2.19 …

The exploration of thermoelectric materials is challenging considering the large materials space, combined with added exponential degrees of freedom coming from doping and the diversity of synthetic pathways. Here, historical data is incorporated, and is updated using experimental feedback by employing error‐correction learning (ECL). This is achieved by learning from prior datasets and then adapting the model to differences in synthesis and characterization that are otherwise difficult to parameterize. This strategy is thus applied to discovering thermoelectric materials, where synthesis is prioritized at temperatures <300 °C. A previously unexplored chemical family of thermoelectric materials, PbSe:SnSb, is documented, finding that the best candidate in this chemical family, 2 wt% SnSb doped PbSe, exhibits a power factor more than 2× that of PbSe. The investigations herein reveal that a closed‐loop …

Surface passivation by thin-slab 2D perovskites is an effective method to suppress interfacial carrier recombination of 3D metal halide perovskite photoabsorbers. However, improving device performance by integrating such 2D/3D perovskite heterojunctions in the sunward, transparent contacts of perovskite solar cells is not evident due to the high exciton binding energies of phase-pure 2D perovskites, which may result in inefficient free-carrier generation and collection. Here, we overcome this challenge by tuning the dimensionality of 2D perovskites via structural isomers of butylammonium (BA) as a small organic cation, occupying the A-site of the 2D perovskite lattice. The discontinuous iso-BA-based 2D crystals on the 3D perovskite surface yield improved interfacial passivation and enhanced hole extraction. Besides an increased open circuit voltage, this remarkably leads to an enhanced photocurrent (∼1 mA …

The decarbonization of the chemical industry is essential to mitigate carbon dioxide (CO2) emissions. Ethylene (C2H4) is the highest production petrochemical globally. When powered by renewable electricity, the electrochemical conversion of CO2 to C2H4 offers a promising route to low carbon C2H4 production. We perform a detailed techno-economic assessment (TEA) of the CO2 reduction reaction (CO2RR) process, converting CO2 from an industrial point source to polymer-grade C2H4. We pair the CO2 electrolyzer with industrially mature upstream and downstream separation technologies in an Aspen Plus model. This comprehensive approach enables us to assess the valorization of both gas and liquid byproduct streams at commercial specification and assess the viability of these processes as a function of scale. We demonstrate that a minimum plant size of ∼3,000 tonne C2H4/year is needed to achieve …

Compared with the n-i-p structure, inverted (p-i-n) perovskite solar cells (PSCs) promise increased operating stability, but these photovoltaic cells often exhibit lower power conversion efficiencies (PCEs) because of nonradiative recombination losses, particularly at the perovskite/C60 interface. We passivated surface defects and enabled reflection of minority carriers from the interface into the bulk using two types of functional molecules. We used sulfur-modified methylthio molecules to passivate surface defects and suppress recombination through strong coordination and hydrogen bonding, along with diammonium molecules to repel minority carriers and reduce contact-induced interface recombination achieved through field-effect passivation. This approach led to a fivefold longer carrier lifetime and one-third the photoluminescence quantum yield loss and enabled a certified quasi-steady-state PCE of 25.1% for …

Pseudo-halide (PH) anion engineering has emerged as a surface passivation strategy of interest for perovskite-based optoelectronics; but until now, PH anions have led to insufficient defect passivation and thus to undesired deep impurity states. The size of the chemical space of PH anions (>106 molecules) has so far limited attempts to explore the full family of candidate molecules. We created a machine learning workflow to speed up the discovery process using full-density functional theory calculations for training the model. The physics-informed machine learning model allowed us to pinpoint promising molecules with a head group that prevents lattice distortion and anti-site defect formation, and a tail group optimized for strong attachment to the surface. We identified 15 potential bifunctional PH anions with the ability to passivate both donors and acceptors, and through experimentation, discovered that sodium …

The tunable bandgaps and facile fabrication of perovskites make them attractive for multi-junction photovoltaics,. However, light-induced phase segregation limits their efficiency and stability, –: this occurs in wide-bandgap (>1.65 electron volts) iodide/bromide mixed perovskite absorbers, and becomes even more acute in the top cells of triple-junction solar photovoltaics that require a fully 2.0-electron-volt bandgap absorber,. Here we report that lattice distortion in iodide/bromide mixed perovskites is correlated with the suppression of phase segregation, generating an increased ion-migration energy barrier arising from the decreased average interatomic distance between the A-site cation and iodide. Using an approximately 2.0-electron-volt rubidium/caesium mixed-cation inorganic perovskite with large lattice distortion in the top subcell, we fabricated all-perovskite triple-junction solar cells and achieved an …

Alkali hydroxide systems capture CO2 as carbonate; however, generating a pure CO2 stream requires significant energy input, typically from thermal cycling to 900°C. What is more, the subsequent valorization of gas-phase CO2 into products presents additional energy requirements and system complexities, including managing the formation of (bi)carbonate in an electrolyte and separating unreacted CO2 downstream. Here, we report the direct electrochemical conversion of CO2, captured in the form of carbonate, into multicarbon (C2+) products. Using an interposer and a Cu/CoPc-CNTs electrocatalyst, we achieve 47% C2+ Faradaic efficiency at 300 mA cm−2 and a full cell voltage of 4.1 V. We report 56 wt % of C2H4 and no detectable C1 gas in the product gas stream: CO, CH4, and CO2 combined total below 0.9 wt % (0.1 vol %). This approach obviates the need for energy to regenerate lost CO2, an issue …

The alloyed lead/tin (Pb/Sn) halide perovskites have gained significant attention in the development of tandem solar cells and other optoelectronic devices due to their widely tunable absorption edge. To gain a better understanding of the intriguing properties of Pb/Sn perovskites, such as their anomalous bandgap’s dependence on stoichiometry, it is important to deepen the understanding of their chemical behavior and local structure. Herein, we investigate a series of two-dimensional Ruddlesden–Popper (RP) and Dion–Jacobson (DJ) phase alloyed Pb/Sn bromide perovskites using butylammonium (BA) and 3-(aminomethyl)pyridinium (3AMPY) as the spacer cations: (BA)2(MA)n−1PbxSnn–xBr3n+1 (n = 1–3) and (3AMPY)(MA)n−1PbxSnn–xBr3n+1 (n = 1–3) through a solution-based approach. Our results show that the ratio and site preference of Pb/Sn atoms are influenced by the layer thickness (n) and spacer …

Achieving control over the transport properties of charge carriers is a crucial aspect of realizing high-performance electronic materials. In metal-halide perovskites, which offer convenient manufacturing traits and tunability for certain optoelectronic applications, this is challenging: the perovskite structure itself poses fundamental limits to maximum dopant incorporation. Here, we demonstrate an organic modifier incorporation strategy capable of modulating the electronic density of states in halide tin perovskites without altering the perovskite lattice, in a similar fashion to substitutional doping in traditional semiconductors. By incorporating organic small molecules and conjugated polymers into cesium tin iodide (CsSnI3) perovskites, we achieve carrier density tunability over 2.7 decades, transition from a temperature-dependent semiconducting to a metallic nature, and high electrical conductivity exceeding 200 S/cm. We …

Electrochemical conversion of CO2 is a promising technology that uses renewable electricity to produce valuable chemicals with lower emissions than traditional methods. However, to make this technology commercially viable, it is crucial to run CO2RR at current densities higher than 200 mA/cm2, as determined by techno-economic analysis. This enables the amortization of electrolyzer capital costs over the typical operating lifetime of a potential commercial CO2RR facility. While the field has made progress in meeting this reaction rate target for many products of interest, reducing the operating voltage of CO2 electrolyzers remains a significant challenge. Addressing this challenge could pave the way for more efficient and cost-effective CO2RR technologies.The economic viability of CO2 electrolyzers heavily relies on their operating voltage, which is a crucial performance metric as it defines the energy efficiency …

Colloidal perovskite nanocrystals (PNCs) display bright luminescence for light‐emitting diode (LED) applications; however, they require post‐synthesis ligand exchange that may cause surface degradation and defect formation. In situ‐formed PNCs achieve improved surface passivation using a straightforward synthetic approach, but their LED performance at the green wavelength is not yet comparable with that of colloidal PNC devices. Here, it is found that the limitations of in situ‐formed PNCs stem from uncontrolled formation kinetics: conventional surface ligands confine perovskite nuclei but fail to delay crystal growth. A bifunctional carboxylic‐acid‐containing ammonium hydrobromide ligand that separates crystal growth from nucleation is introduced, leading to the formation of quantum‐confined PNC solids exhibiting a narrow size distribution. Controlled crystallization is further coupled with defect passivation …

Perovskites with low ionic radii metal centres (for example, Ge perovskites) experience both geometrical constraints and a gain in electronic energy through distortion; for these reasons, synthetic attempts do not lead to octahedral [GeI6] perovskites, but rather, these crystallize into polar non-perovskite structures, , , , –. Here, inspired by the principles of supramolecular synthons,, we report the assembly of an organic scaffold within perovskite structures with the goal of influencing the geometric arrangement and electronic configuration of the crystal, resulting in the suppression of the lone pair expression of Ge and templating the symmetric octahedra. We find that, to produce extended homomeric non-covalent bonding, the organic motif needs to possess self-complementary properties implemented using distinct donor and acceptor sites. Compared with the non-perovskite structure, the resulting [GeI6]4− octahedra …

Ge-centered octahedral perovskites have heretofore not been achievable due to collapse of the perovskite structure into non-octahedral units due to a lack of B site support from the small-radius Ge atom, which breaks Goldschmidt’s rules for constructing octahedral perovskites. To overcome this shortcoming, a strategy was developed to form a strong cage with the A sites in which the octahedron is forced to remain intact. Strong intermolecular interaction between the organic A site cations were used to stabilize the symmetric Ge octahedral perovskite beyond the Goldschmidt’s rules. The molecules used based on Y-PMA (Y: F, Cl, Br, I) that facilitated strong halogen bonding to form the cage around the octahedral. Octahedral Ge perovskites exhibit a direct bandgap in contrast to the indirect bandgap of non-octahedral Ge perovskites are demonstrated. In addition, the octahedral Ge perovskite exhibited a dramatic …

Aspects included herein include an electrolytic system for electrochemical reduction of carbon dioxide, the system comprising: a cathode comprising: a porous gas-diffusion membrane permeable to CO 2; an electrocatalyst layer adjacent to a second side of the gas-diffusion membrane; the electrocatalyst layer comprising: an electrically conductive catalyst; and a selectivity-determining organic material attached to at least a portion of the electrically conductive catalyst; wherein: the organic material is formed of a plurality of oligomers; each oligomer comprises a plurality of covalently bonded base units; each base unit comprises at least one heterocyclic group having at least one nitrogen in its structure; and an anion exchange membrane adjacent to the electrocatalyst layer and positioned between the anode and the cathode; wherein anion exchange membrane is characterized by anion conductivity and the cathode …

Cement production is a carbon-intensive industrial process, with the sector contributing ∼8% of global anthropogenic CO2 emissions. On average, producing each kilogram of cement leads to the emission of 1 kg of CO2─the combination of fuel combustion emissions and carbon released from the feedstock, limestone (CaCO3). Here we report electrochemical cement production based on anion-mediated electrochemical calcium extraction (ECE) that addresses both feedstock and energy emissions. The in situ-generated acidic electrolytes release the feedstock CO2 emissions at high purity, enabling direct carbon utilization or sequestration without costly capture and purification steps. Energy embodied within a separate H2 output stream is sufficient to sinter Ca(OH)2 to produce portland cement, thus removing the CO2 emissions associated with fuel combustion. We then replace CaCO3 with a carbon-free calcium …

Organic electrode materials have emerged as promising solutions for numerous energy applications. However, their full utility is impeded by their limited stability and inherently poor conductivity. To address these issues, one approach is to use functional conjugated polymers to replace the conventional insulating poly(vinylidene fluoride) (PVDF) binder that may facilitate ion/electron transport and stabilize the electrode. In this study, we report the synthesis of a series of sulfonamide π-conjugated small molecules, linear oligomers, and two-dimensional polymers and their subsequent use as binder materials for organic electrodes. We observe an enhanced specific capacity in a perylenetetracarboxylic dianhydride (PTCDA) composite electrode. The impact of dimensionality is evaluated through the battery performance. The two-dimensional sulfonamide polymer affords a 3-fold improvement in capacity retention …

We investigated the role of hollow perovskite architectures in enhancing the photostability of mixed halide wide-bandgap perovskites. We focused on mitigating photoluminescence (PL) peak shifts caused by phase segregation when exposed to light. By analyzing the optical and structural properties of mixed bromide/iodide hollow perovskite thin films, we observed that the incorporation of hollow structures reduced the ionic conductivity in the films, leading to improved photostability compared to non-hollow perovskite samples. The mixed halide hollow perovskite thin films exhibited increased the bandgap. High-power laser irradiation was used to induce phase segregation, and changes in the PL emission spectra were measured as a function of irradiation time. The mixed halide hollow perovskite thin films exhibited reduced PL peak shifts compared to the control samples. The inclusion of enI2 (en …

The present invention provides quantum dot (QD)-in-matrix materials for use in blue light emitting diodes, wherein the QD-in-matrix material comprises a plurality of quantum dots embedded in a doped lead perovskite matrix.

Fabricating all-perovskite tandem solar cells (APTSCs) is promising to overcome the thermodynamic limit of single-junction perovskite solar cells. Here, we demonstrate efficient and stable APTSCs based on Pb-based perovskites - a 1.91 eV cesium lead iodide bromide (CsPbI2Br) and a 1.51 eV formamidinium cesium lead triiodide (FA0.95Cs0.05PbI3). We introduce poly[3-(4-methylamine carboxybutyl)thiophene] (P3CT-N) to modify NiOx hole transport layer (HTL) for the wide-bandgap CsPbI2Br cells. The HTL surface modification enhances charge extraction and suppresses the formation of the detrimental interfacial layer, leading to high performance and stability of wide-bandgap CsPbI2Br solar cells. These advances allow us to demonstrate efficient and stable all-Pb APTSCs consisting of CsPbI2Br/FA0.95Cs0.05PbI3 subcells with power conversion efficiencies (PCEs) exceeding 22% and an operational …

III‐V colloidal quantum dots (CQDs) are promising materials for optoelectronic applications, for they avoid heavy metals while achieving absorption spanning the visible to the infrared (IR). However, the covalent nature of III‐V CQDs requires the development of new passivation strategies to fabricate conductive CQD solids for optoelectronics: this work shows herein that ligand exchanges, previously developed in II‐VI and IV‐VI quantum dots and employing a single ligand, do not fully passivate CQDs, and that this curtails device efficiency. Guided by density functional theory (DFT) simulations, this work develops a co‐passivation strategy to fabricate indium arsenide CQD photodetectors, an approach that employs the combination of X‐type methyl ammonium acetate (MaAc) and Z‐type ligands InBr3. This approach maintains charge carrier mobility and improves passivation, seen in a 25% decrease in Stokes shift, a …

2020-11-13 Assigned to THE GOVERNING COUNCIL OF THE UNIVERSITY OF TORONTO reassignment THE GOVERNING COUNCIL OF THE UNIVERSITY OF TORONTO NUNC PRO TUNC ASSIGNMENT (SEE DOCUMENT FOR DETAILS). Assignors: CHOI, JONGMIN, CHE, Fanglin, HOOGLAND, SJOERD, KIM, YOUNGHOON, SARGENT, EDWARD H., GARCIA DE ARQUER, Francisco Pelayo, JO, JEA WOONG

Regulating the strain of inorganic perovskites has emerged as a critical approach to control their electronic and optical properties. Here, an alternative strategy to further control the piezoelectric properties by substituting the halogen atom (I/Br) in the CsPbX3 perovskite (X = Cl, Br) structure is adopted. A series of piezoelectric materials with excellent piezoelectric coefficients (d33) are unveiled. Iodine‐incorporated CsPbBr2I demonstrates the record intrinsic piezoelectric response (d33 ≈47 pC N−1) among all inorganic metal halide perovskites. This leads to an excellent electrical output power of ≈ 0.375 mW (24.8 µW cm−2 N−1) in the piezoelectric energy generator (PEG) which is higher than those of the pristine/mixed perovskite references with CsPbX3 (X = I, Br, Cl). With its structural phase remaining unchanged, the strained CsPbBr2I retains its superior piezoelectricity in both thin film and nanocrystal powder …

The electrochemical reduction of CO2 using copper-based electrocatalysts offers a route to produce high-value multicarbon (C2+) products from renewable electricity (Nat. Catal. 4, 952-958 (2021); Nature 614, 262-269 (2023)). To date, the efficient electrocatalytic conversion of CO2 to multicarbon products has only been possible when using impurity-free CO2 sources, such as from direct air capture. The generation of such high-grade CO2 streams is expensive, accounting for almost half of the total energy required for both capture and electroreduction processes (Nat. Catal. 4, 952-958 (2021)). Conversely, capturing CO2 from point sources, such as industrial flue gas, is more efficient due to the higher concentration of CO2 in the feed. However, trace amounts of sulfur dioxide (10 ~ 400 ppm SO2) inherently present in these streams will significantly degrade the CO2 conversion process. All previous attempts to …

Sluggish kinetics of the anodic oxygen evolution reaction (OER) and minor upstream upsets in feed water quality remain bottlenecks for efficient water electrolysis, which is exacerbated under near-neutral pH environments due to H2O dissociation. In this work, we report the introduction of a NiSx interlayer in a Co-(NiFe) oxide/nitride catalyst on nickel foam substrate. Postmortem OER characterization in neutral pH synthetic seawater (SSW) shows that stable cationic [Co-(NiFe)]δ+ and anionic [O-N]δ– surface species coupled with the NiSx interlayer accelerate H2O dissociation, thereby enhancing activity and kinetics. The electrocatalysts exhibit stable performance at 100 mA cm−2 for 50 h in alkaline and neutral pH SSW with 350 and 425 mV of overpotential, respectively. The faradaic efficiency of the NiSx interlayer catalysts is enhanced by 10.3% and 8.5% achieving 94.5% and 87.4% under alkaline and neutral pH …

Acidic electrochemical CO2 reduction (CO2R) addresses CO2 loss and thus mitigates the energy penalties associated with CO2 recovery; however, acidic CO2R suffers low selectivity. One promising remedy—using a high concentration of alkali cations—steers CO2R towards multi-carbon (C2+) products, but these same alkali cations result in salt formation, limiting operating stability to <15 h. Here we present a copper catalyst functionalized with cationic groups (CG) that enables efficient CO2 activation in a stable manner. By replacing alkali cations with immobilized benzimidazolium CG within ionomer coatings, we achieve over 150 h of stable CO2R in acid. We find the water-management property of CG minimizes proton migration that enables operation at a modest voltage of 3.3 V with mildly alkaline local pH, leading to more energy-efficient CO2R with a C2+ Faradaic efficiency of 80 ± 3%. As a result, we …

The direct air capture (DAC) of carbon dioxide (CO2) can potentially contribute to mitigating past and offsetting hard-to-abate future emissions; however, the regeneration of DAC capture liquids requires high temperatures and thermal energy inputs with emissions that diminish their net environmental benefit. Here, we present a low-temperature electrochemical process to regenerate alkaline capture liquids via alternating electrocatalysis (AE). Colocating oxidation and reduction reactions on a single electrode, cycled between electrolyzer and fuel cell modes, mitigates film formation and losses in the regeneration of alkali hydroxide and hydrogen halide. CO2 can be captured and released with an energy input of 6.4 GJ/tCO2 at 100 mA cm−2 and an emission intensity of ∼11 kg CO2e/tCO2.

The use of forward-bias bipolar membranes (f-BPM) in CO2 electrolyzers offers the advantage of avoiding costly CO2 reactant loss. However, current f-BPM-based electrolyzers require a high voltage and produce H2 at the expense of CO2 reduction products. In this work, we develop a direct membrane deposition (DMD) approach that combines anion and cation exchange membranes (AEM and CEM, respectively) to increase transport and facilitate CO2 regeneration. The DMD approach provides flexibility to tune the properties of the composite and optimize the AEM:CEM ratio for low resistance and low H2 evolution. Compared to a standard f-BPM, the DMD approach reduced the H2 Faradaic efficiency by 2-fold (25% vs 12%, respectively), reduced mass transport resistance by over 50%, decreased full-cell potential by 0.84 V, increased the selectivity toward multicarbon products by over 2-fold (29% vs 65 …

Methods and systems for mRNA analysis and quantification of mRNA expression in cells are provided. An example method includes introducing a first capture probe and a second capture probe into the cells, the first capture probe and the second capture probe each configured to be complementary to a respective section of target mRNA within the cells, wherein binding of the first and second capture probes to the respective sections of the target mRNA results in tagging of the cells and causes the first and second capture probes to form clusters with each other. The first capture probe and the second capture probe are each bound to magnetic nanoparticles (MNPs) that, when trapped within the tagged cells, cause the tagged cells to be susceptible to magnetic forces. The method and system further include introducing the cells into a device configured to magnetically capture tagged cells.

The carbon dioxide and carbon monoxide electroreduction reactions, when powered using low-carbon electricity, offer pathways to the decarbonization of chemical manufacture,. Copper (Cu) is relied on today for carbon–carbon coupling, in which it produces mixtures of more than ten C2+ chemicals, , –: a long-standing challenge lies in achieving selectivity to a single principal C2+ product, –. Acetate is one such C2 compound on the path to the large but fossil-derived acetic acid market. Here we pursued dispersing a low concentration of Cu atoms in a host metal to favour the stabilization of ketenes—chemical intermediates that are bound in monodentate fashion to the electrocatalyst. We synthesize Cu-in-Ag dilute (about 1 atomic per cent of Cu) alloy materials that we find to be highly selective for acetate electrosynthesis from CO at high *CO coverage, implemented at 10 atm pressure. Operando X-ray …

Real-time biomolecular monitoring requires biosensors based on affinity reagents, such as aptamers, with moderate to low affinities for the best binding dynamics and signal gain. We recently reported Pro-SELEX, an approach that utilizes parallelized SELEX and high-content bioinformatics for the selection of aptamers with predefined binding affinities. The Pro-SELEX pipeline relies on an algorithm, termed AptaZ, that can predict the binding affinities of selected aptamers. The original AptaZ algorithm is computationally complex and slows the overall throughput of Pro-SELEX. Here, we present Apta FastZ, a rapid equivalent of AptaZ. The Apta FastZ algorithm considers the spare nature of the sequences from SELEX and is coded to avoid unnecessary comparison between sequences. As a result, Apta FastZ achieved a 10 to 40-fold faster computing speed compared to the original AptaZ algorithm while maintaining …

Renewable CH4 produced from electrocatalytic CO2 reduction is viewed as a sustainable and versatile energy carrier, compatible with existing infrastructure. However, conventional alkaline and neutral CO2-to-CH4 systems suffer CO2 loss to carbonates, and recovering the lost CO2 requires input energy exceeding the heating value of the produced CH4. Here we pursue CH4-selective electrocatalysis in acidic conditions via a coordination method, stabilizing free Cu ions by bonding Cu with multidentate donor sites. We find that hexadentate donor sites in ethylenediaminetetraacetic acid enable the chelation of Cu ions, regulating Cu cluster size and forming Cu-N/O single sites that achieve high CH4 selectivity in acidic conditions. We report a CH4 Faradaic efficiency of 71% (at 100 mA cm−2) with <3% loss in total input CO2 that results in an overall energy intensity (254 GJ/tonne CH4), half that of existing …

Machine learning models of material properties accelerate materials discovery, reproducing density functional theory calculated results at a fraction of the cost, , , , –. To bridge the gap between theory and experiments, machine learning predictions need to be distilled in the form of interpretable chemical rules that can be used by experimentalists. Here we develop a framework to address this gap by combining evolutionary algorithm-powered search with machine-learning surrogate models. We then couple the search results with supervised learning and statistical testing. This strategy enables the efficient search of a materials space while providing interpretable design rules. We demonstrate its effectiveness by developing rules for the design of direct bandgap materials, stable UV emitters, and IR perovskite emitters. Finally, we conclusively show how DARWIN-generated rules are statistically more robust and …

Inverted perovskite solar cells (PSCs) promise enhanced operating stability compared to their normal-structure counterparts, –. To improve efficiency further, it is crucial to combine effective light management with low interfacial losses,. Here we develop a conformal self-assembled monolayer (SAM) as the hole-selective contact on light-managing textured substrates. Molecular dynamics simulations indicate that cluster formation during phosphonic acid adsorption leads to incomplete SAM coverage. We devise a co-adsorbent strategy that disassembles high-order clusters, thus homogenizing the distribution of phosphonic acid molecules, and thereby minimizing interfacial recombination and improving electronic structures. We report a laboratory-measured power conversion efficiency (PCE) of 25.3% and a certified quasi-steady-state PCE of 24.8% for inverted PSCs, with a photocurrent approaching 95% of the …

Body-based biomolecular sensing systems, including wearable, implantable and consumable sensors allow comprehensive health-related monitoring. Glucose sensors have long dominated wearable bioanalysis applications owing to their robust continuous detection of glucose, which has not yet been achieved for other biomarkers. However, access to diverse biological fluids and the development of reagentless sensing approaches may enable the design of body-based sensing systems for various analytes. Importantly, enhancing the selectivity and sensitivity of biomolecular sensors is essential for biomarker detection in complex physiological conditions. In this Review, we discuss approaches for the signal amplification of biomolecular sensors, including techniques to overcome Debye and mass transport limitations, and selectivity improvement, such as the integration of artificial affinity recognition elements. We …

The electrochemical CO2 reduction reaction (CO2RR) is one way of mitigating the rising levels of anthropogenic CO2 emissions. Most of the advancements in the CO2RR field have been implemented in basic or neutral electrolytes where a major fraction of the input CO2 converts to carbonate ions through reaction with OH– (Science 360, 783-787 (2018); Nat. Catal. 5, 564-570 (2022)). These approaches result in low carbon efficiency (the percentage of CO2 converted per total CO2 input), typically below 20% toward multicarbon products, resulting in severe energy and cost penalty (Nat. Sustain. 5, 563-573 (2022)).Performing CO2RR in acidic conditions reduces reactant loss to carbonates. In this condition, the (bi)carbonate ion crossover/formation is countered by the high proton concentration in the electrolyte. However, the unshielded cathode surface favors the hydrogen evolution reaction (HER) over CO2RR …

Developing accurate and actionable physical models of degradation mechanisms in perovskite solar cells (PSCs) will be essential to developing bankable technologies. Princeton researchers have recently shown that the temperature-dependent degradation of all-inorganic PSCs follows the Arrhenius equation and mechanistically assigned the leading cause of degradation to iodide diffusion. With an ion-blocking two-dimensional capping layer, they achieve a projected 5 years of operating stability for PSCs based on an accelerated aging model.

Perovskite solar cells have demonstrated the efficiencies needed for technoeconomic competitiveness. With respect to the demanding stability requirements of photovoltaics, many techniques have been used to increase the stability of perovskite solar cells, and tremendous improvements have been made over the course of a decade of research. Nevertheless, the still-limited stability of perovskite solar cells remains to be fully understood and addressed. In this Review, we summarize progress in single-junction, lead-based perovskite photovoltaic stability and discuss the origins of chemical lability and how this affects stability under a range of relevant stressors. We highlight categories of prominent stability-enhancing strategies, including compositional tuning, barrier layers and the fabrication of stable transport layers. In the conclusion of this Review, we discuss the challenges that remain, and we offer a perspective …

Industrial water splitting pairs cathodic hydrogen evolution with oxygen evolution at the anode, the latter generating low-value oxygen as the oxidative product. We reasoned that replacing the oxygen evolution reaction (OER) with anodic electrosynthesis of acetic acid from ethanol at industrial current densities could be a route to increase the economic efficiency of green hydrogen production. We partition the selective oxidation of ethanol to acetic acid into two mechanistically distinct transformations: first ethanol oxidation followed by the production of *OH. Density functional theory (DFT) studies show that the aldehyde-derived intermediate CH3CO* from ethanol oxidation and the *OH radical from water dissociation are both needed in the electroproduction of acetic acid. Operando Fourier transform infrared (FTIR) spectroscopy identifies the corresponding aldehyde intermediates on the anode surface. Based on …

Heavy-metal-free III–V colloidal quantum dots (CQDs) show promise in optoelectronics: Recent advancements in the synthesis of large-diameter indium arsenide (InAs) CQDs provide access to short-wave infrared (IR) wavelengths for three-dimensional ranging and imaging. In early studies, however, we were unable to achieve a rectifying photodiode using CQDs and molybdenum oxide/polymer hole transport layers, as the shallow valence bandedge (5.0 eV) was misaligned with the ionization potentials of the widely used transport layers. This occurred when increasing CQD diameter to decrease the bandgap below 1.1 eV. Here, we develop a rectifying junction among InAs CQD layers, where we use molecular surface modifiers to tune the energy levels of InAs CQDs electrostatically. Previously developed bifunctional dithiol ligands, established for II-VI and IV-VI CQDs, exhibit slow reaction kinetics with III-V …

In the III–V family of colloidal quantum dot (CQD) semiconductors, InSb promises access to a wider range of infrared wavelengths compared to many light‐sensing material candidates. However, achieving the necessary size, size‐dispersity, and optical properties has been challenging. Here the synthetic challenges associated with InSb CQDs are investigated and it is found that uncontrolled reduction of the antimony precursor hampers the controlled growth of CQDs. To overcome this, a synthetic strategy that combines nonpyrophoric precursors with zinc halide additives is developed. The experimental and computational studies show that zinc halide additives decelerate the reduction of the antimony precursor, facilitating the growth of more uniformly sized CQDs. It is also found that the halide choice provides additional control over the strength of this effect. The resultant CQDs exhibit well‐defined excitonic …

Electrochemical CO2 reduction (CO2R) is an approach to closing the carbon cycle for chemical synthesis. To date, the field has focused on the electrolysis of ambient pressure CO2. However, industrial CO2 is pressurized—in capture, transport and storage—and is often in dissolved form. Here, we find that pressurization to 50 bar steers CO2R pathways toward formate, something seen across widely-employed CO2R catalysts. By developing operando methods compatible with high pressures, including quantitative operando Raman spectroscopy, we link the high formate selectivity to increased CO2 coverage on the cathode surface. The interplay of theory and experiments validates the mechanism, and guides us to functionalize the surface of a Cu cathode with a proton-resistant layer to further the pressure-mediated selectivity effect. This work illustrates the value of industrial CO2 sources as the starting feedstock …

The invention relates to a composite multilayer carbon dioxide (CO 2) reduction catalyst, comprising a catalyst layer comprising at least one metal compound, the catalyst layer having opposed first and second sides; a hydrophobic gas-diffusion layer provided on the first side of the catalyst layer; a current collection structure provided on the second side of the catalyst layer. The metal is preferably copper. The invention also relates to a method for electrochemical production of a hydrocarbon product, such as ethylene, using said catalyst.

Aptamers are being applied as affinity reagents in analytical applications owing to their high stability, compact size and amenability to chemical modification. Generating aptamers with different binding affinities is desirable, but systematic evolution of ligands by exponential enrichment (SELEX), the standard for aptamer generation, is unable to quantitatively produce aptamers with desired binding affinities and requires multiple rounds of selection to eliminate false-positive hits. Here we introduce Pro-SELEX, an approach for the rapid discovery of aptamers with precisely defined binding affinities that combines efficient particle display, high-performance microfluidic sorting and high-content bioinformatics. Using the Pro-SELEX workflow, we were able to investigate the binding performance of individual aptamer candidates under different selective pressures in a single round of selection. Using human myeloperoxidase …

Band gap tuning in mixed-halide perovskites enables efficient multijunction solar cells and LEDs. However, these wide band gap perovskites, which contain a mixture of iodide and bromide ions, are known to phase segregate under illumination, introducing voltage losses that limit stability. Previous studies have employed inorganic perovskites, halide alloys, and grain/interface passivation to minimize halide segregation, yet photostability can be further advanced. By focusing on the role of halide vacancies in anion migration, one expects to be able to erect local barriers to ion migration. To achieve this, we employ a 3D “hollow” perovskite structure, wherein a molecule that is otherwise too large for the perovskite lattice is incorporated. The amount of hollowing agent, ethane-1,2-diammonium dihydroiodide (EDA), varies the density of the hollow sites. Photoluminescence measurements reveal that 1% EDA in the …

Colloidal quantum dot (CQD) photodetectors (PDs) can detect wavelengths longer than the 1100 nm limit of silicon because of their highly tunable bandgaps. CQD PDs are acutely affected by the ligands that separate adjacent dots in a CQD-solid. Optimizing the exchange solution ligand concentration in the processing steps is crucial to achieving high photodetector performance. However, the complex mix of chemistry and optoelectronics involved in CQD PDs means that the effects of the exchange solution ligand concentration on device physics are poorly understood. Here we report direct correspondence between simulated and experimental transient photocurrent responses in CQD PDs. For both deficient and excess conditions, our model demonstrated the experimental changes to the transient photocurrent aligned with changes in trap state density. Combining transient photoluminescence, absorption, and …