Electrical Tunability of Quantum-Dot-in-Perovskite Solids.

The quantum-dot-in-perovskite matrix (DIM) is an emerging class of semiconductors for optoelectronics enabled by their complementary charge transport properties and stability improvements. However, a detailed understanding of the pure electrical properties in DIM is still in its early stage. Here, we developed PbS quantum dot-in-CsSnI matrix solids exhibiting improved electrical properties and enhanced stability.

Amidination of ligands for chemical and field-effect passivation stabilizes perovskite solar cells.

Surface passivation has driven the rapid increase in the power conversion efficiency (PCE) of perovskite solar cells (PSCs). However, state-of-the-art surface passivation techniques rely on ammonium ligands that suffer deprotonation under light and thermal stress. We developed a library of amidinium ligands, of interest for their resonance effect-enhanced N-H bonds that may resist deprotonation, to increase the thermal stability of passivation layers on perovskite surfaces.

Ruthenium-Substituted Polyoxoanion Serves as Redox Shuttle and Intermediate Stabilizer in Selective Electrooxidation of Ethylene to Ethylene Glycol.

The high carbon intensity of present-day ethylene glycol (EG) production motivates interest in electrifying ethylene oxidation. Noting poor kinetics in prior reports of the organic electrooxidation of small hydrocarbons, we explored the design of mediators that activate and simultaneously stabilize light alkenes. A ruthenium-substituted polyoxometalate (Ru-POM, {Si[Ru(HO)WO]}) achieves 82% faradaic efficiency in EG production at 100 mA/cm under ambient conditions.

Highly Stable Biotemplated InP/ZnSe/ZnS Quantum Dots for Bacterial Monitoring.

Despite their unique optical and electrical characteristics, traditional semiconductor quantum dots (QDs) made of heavy metals or carbon are not ideally suited for biomedical applications. Cytotoxicity and environmental concerns are key limiting factors affecting the adoption of QDs from laboratory research to real-world medical applications. Recently, advanced InP/ZnSe/ZnS QDs have emerged as alternatives to traditional QDs due to their low toxicity and optical properties; however, bioconjugation has remained a challenge due to surface chemistry limitations that can lead to instability in aqueous environments.

High-efficiency and thermally stable FACsPbI perovskite photovoltaics.

α-FACsPbI is a promising absorbent material for efficient and stable perovskite solar cells (PSCs). However, the most efficient α-FACsPbI PSCs require the inclusion of the additive methylammonium chloride, which generates volatile organic residues (methylammonium) that limit device stability at elevated temperatures. Previously, the highest certified power-conversion efficiency of α-FACsPbI PSCs without methylammonium chloride was only approximately 24% (refs.

Acid-Stable Cu Cluster Precatalysts Enable High Energy and Carbon Efficiency in CO Electroreduction.

The electrochemical reduction of CO in acidic media offers the advantage of high carbon utilization, but achieving high selectivity to C products at a low overpotential remains a challenge. We identified the chemical instability of oxide-derived Cu catalysts as a reason that advances in neutral/alkaline electrolysis do not translate to acidic conditions. In acid, Cu ions leach from Cu oxides, leading to the deactivation of the C-active sites of Cu nanoparticles.

Reduced-Dimensional Perovskites: Quantum Well Thickness Distribution and Optoelectronic Properties.

Reduced-dimensional perovskites (RDPs), a large category of metal halide perovskites, have attracted considerable attention and shown high potential in the fields of solid-state displays and lighting. RDPs feature a quantum-well-based structure and energy funneling effects. The multiple quantum well (QW) structure endows RDPs with superior energy transfer and high luminescence efficiency.

Scaling CO Electrolyzer Cell Area from Bench to Pilot.

To contribute meaningfully to carbon dioxide (CO) emissions reduction, CO electrolyzer technology will need to scale immensely. Bench-scale electrolyzers are the norm, with active areas <5 cm. However, cell areas on the order of 100s or 1000s of cm will be required for industrial deployment.

Resurfacing of InAs Colloidal Quantum Dots Equalizes Photodetector Performance across Synthetic Routes.

The synthesis of highly monodispersed InAs colloidal quantum dots (CQDs) is needed in InAs CQD-based optoelectronic devices. Because of the complexities of working with arsenic precursors such as tris-trimethylsilyl arsine ((TMSi)As) and tris-trimethylgermyl arsine ((TMGe)As), several attempts have been made to identify new candidates for synthesis; yet, to date, only the aforementioned two highly reactive precursors have led to excellent photodetector device performance. We begin the present study by investigating the mechanism, finding that the use of the cosurfactant dioctylamine plays a crucial role in producing monodispersed InAs populations.

A synthetic cell-free pathway for biocatalytic upgrading of one-carbon substrates.

Biotechnological processes hold tremendous potential for the efficient and sustainable conversion of one-carbon (C1) substrates into complex multi-carbon products. However, the development of robust and versatile biocatalytic systems for this purpose remains a significant challenge. In this study, we report a hybrid electrochemical-biochemical cell-free system for the conversion of C1 substrates into the universal biological building block acetyl-CoA.

Efficient Deep-Blue Light-Emitting Diodes Through Decoupling of Colloidal Perovskite Quantum Dots.

Metal halide perovskite light-emitting diodes (PeLEDs) have exceptional color purity but designs that emit deep-blue color with high efficiency have not been fully achieved and become more difficult in the thin film of confined perovskite colloidal quantum dots (PeQDs) due to particle interaction. Here it is demonstrated that electronic coupling and energy transfer in PeQDs induce redshift in the emission by PeQD film, and consequently hinder deep-blue emission. To achieve deep-blue emission by avoiding electronic coupling and energy transfer, a QD-in-organic solid solution is introduced to physically separate the QDs in the film.

Spiky Gold Nanoparticles, a Nanoscale Approach to Enhanced Ex Vivo T-Cell Activation.

While existing synthetic technologies for ex vivo T-cell activation face challenges like suboptimal expansion rates and low effectiveness, artificial antigen-presenting cells (aAPCs) hold great promise for enhanced T-cell based therapies. In particular, gold nanoparticles (AuNPs), known for their biocompatibility, ease of synthesis, and versatile surface chemistry, are strong candidates for use as nanoscale aAPCs. In this study, we developed spiky AuNPs with branched geometries to present activating ligands to primary human T-cells.

Two-dimensional perovskitoids enhance stability in perovskite solar cells.

Two-dimensional (2D) and three-dimensional (3D) perovskite heterostructures have played a key role in advancing the performance of perovskite solar cells. However, the migration of cations between 2D and 3D layers results in the disruption of octahedral networks, leading to degradation in performance over time. We hypothesized that perovskitoids, with robust organic-inorganic networks enabled by edge- and face-sharing, could impede ion migration.

Pourbaix Machine Learning Framework Identifies Acidic Water Oxidation Catalysts Exhibiting Suppressed Ruthenium Dissolution.

The demand for green hydrogen has raised concerns over the availability of iridium used in oxygen evolution reaction catalysts. We identify catalysts with the aid of a machine learning-aided computational pipeline trained on more than 36,000 mixed metal oxides. The pipeline accurately predicts Pourbaix decomposition energy () from unrelaxed structures with a mean absolute error of 77 meV per atom, enabling us to screen 2070 new metallic oxides with respect to their prospective stability under acidic conditions.

Energy transition needs new materials.

The decreasing cost of electricity worldwide from wind and solar energy, as well as that of end-use technologies such as electric vehicles, reflect substantial progress made toward replacing fossil fuels with alternative energy sources. But a full transition to clean energy can only be realized if numerous challenges are overcome. Many problems can be addressed through the discovery of new materials that improve the efficiency of energy production and consumption; reduce the need for scarce mineral resources; and support the production of green hydrogen, clean ammonia, and carbon-neutral hydrocarbon fuels.

Phenotypic targeting using magnetic nanoparticles for rapid characterization of cellular proliferation regulators.

Genome-wide CRISPR screens have provided a systematic way to identify essential genetic regulators of a phenotype of interest with single-cell resolution. However, most screens use live/dead readout of viability to identify factors of interest. Here, we describe an approach that converts cell proliferation into the degree of magnetization, enabling downstream microfluidic magnetic sorting to be performed.

Bimetallic Metal Sites in Metal-Organic Frameworks Facilitate the Production of 1-Butene from Electrosynthesized Ethylene.

Converting CO to synthetic hydrocarbon fuels is of increasing interest. In light of progress in electrified CO to ethylene, we explored routes to dimerize to 1-butene, an olefin that can serve as a building block to ethylene longer-chain alkanes. With goal of selective and active dimerization, we investigate a series of metal-organic frameworks having bimetallic catalytic sites.

Improved charge extraction in inverted perovskite solar cells with dual-site-binding ligands.

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.

Nickel Oxide Hole Injection Layers for Balanced Charge Injection in Quantum Dot Light-Emitting Diodes.

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 NiO 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 NiO is explored.

Ligand-modified nanoparticle surfaces influence CO electroreduction selectivity.

Improving the kinetics and selectivity of CO/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.

CO Electrolyzers.

CO 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 CO feeds and downstream separation processes in a way that minimizes overall product energy intensity and presents viable use cases.

Engineering colloidal semiconductor nanocrystals for quantum information processing.

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.

Selective Electrified Propylene-to-Propylene Glycol Oxidation on Activated Rh-Doped Pd.

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 dynamic adsorption affinity of ligands is a surrogate for the passivation of surface defects.

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.