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The thermally stable inorganic cesium‐based perovskites promise efficient and stable photovoltaics. Unfortunately, the strong ionic bonds lead to uncontrollable rapid crystallization, making it difficult in fabricating large‐area black‐phase film for photovoltaics. Herein, we developed a facile hydrogen‐bonding assisted strategy for modulating the crystallization of CsPbI2Br to achieve uniform large‐area phase‐pure films with much‐reduced defects. The simple addition of methylamine acetate in precursors not only promotes the formation of intermediate phase via hydrogen bonding to circumvent the direct crystallization of CsPbI2Br from ionic precursors but also widens the film processing window, thus enabling to fabricate large‐area high‐quality phase‐pure CsPbI2Br film under benign conditions. Combining with stable dopant‐free poly(3‐hexylthiophene), the CsPbI2Br solar cells achieve the record‐high efficiencies of 18.14 % and 16.46 % for 0.1 cm2 and 1 cm2 active area, respectively. The obtained high efficiency of 38.24 % under 1000 lux illumination suggests its potential in indoor photovoltaics for powering the Internet of Things, etc. [ABSTRACT FROM AUTHOR]

Highly active oxygen evolution reaction (OER) electrocatalysts, such as those containing Fe, often face the challenge of severe dissolution of active elements. Addressing this concern through the establishment of a dynamically stable interface during OER presents a promising strategy, achieved by manipulation of catalyst components. Herein, the findings reveal that Fe loss during OER predominantly occurs during the initial activation phase, marked by irreversible structural distortion that disrupts interfacial dynamical stability. By investigating the structural evolution of Fe‐containing Prussian blue analogs, serving as a model OER precatalyst, the correlation between precatalyst structural changes and interfacial dynamic stability is elucidated. Utilizing thermal annealing of CoFe bimetal Prussian blue, favorable thermodynamic conditions are induced for generating cyano vacancies within the matrix, thereby facilitating enhanced initial activation during OER. Consequently, catalytically active and stable oxyhydroxide species rapidly form at the interface, exhibiting robust interactions with interfacial Fe elements to stabilize interface dynamics. Suppression of the irreversible structural distortion responsible for active element loss during initial activation culminates in enhanced OER activity and stability. [ABSTRACT FROM AUTHOR]

Electrochemically converting CO2 back into fuels and chemicals is promising in alleviating the greenhouse effect worldwide. Various high‐efficiency catalysts have been achieved, yet the unsatisfied structural stability under CO2 electrolysis conditions restricts their practical application. Herein, a sub‐5 nm sized CuInS2 quantum dots (CIS‐QDs) based electrocatalyst for converting CO2 into CO are developed. Taking advantage of the stable M─Ch (metal‐chalcogenide) covalent bonds, and unique p‐block metal properties, the as‐prepared catalyst exhibits excellent structural stability under large overpotentials and can achieve a high CO Faradaic efficiency (FE) of 86% (total CO2 reduction FE of 89%) at −0.65 V versus reversible hydrogen electrode with long‐term durability of 40 h and outstanding current densities of 10.6 mA cm−2 simultaneously. Furthermore, detailed electrochemical analyses revealed that the excellent performance of the as‐prepared catalysts shall be attributed to the high‐density active sites and fast charge transfer brought by the ultrasmall size of CIS‐QDs. This work provides insights into the design of high‐density and stable catalytic sites for developing high‐performance electrocatalysts. [ABSTRACT FROM AUTHOR]

Selenium (Se), as the world's oldest photovoltaic material, has reemerged as a promising absorber material for indoor photovoltaics (IPVs) due to its suitable wide bandgap of ∼1.9 eV, nontoxicity, and excellent inherent stability. However, despite the low material cost of Se, conventional high-performance Se photovoltaic devices usually employ high-cost Au as the electrode, significantly increasing the cost of Se-based devices and restricting their future commercialization. Here we replace high-cost Au with low-cost Cu as the electrode, reducing the cost of Se devices by about one order of magnitude. We further introduce an isolation layer of MoOx between Se and Cu films; this prevents the reaction between Se and Cu to form CuSe during the thermal evaporation of Cu, which significantly lowers the device performance. The resulting Se cells achieve an efficiency of 10.4% under indoor illumination at 500 lux, comparable to that of Au electrode-based Se devices and superior to that of the current IPV industry standard of commercialized amorphous silicon cells with indoor photovoltaic efficiency below 10%. Unencapsulated devices also exhibit negligible efficiency loss after 1000 h of storage under ambient conditions. [ABSTRACT FROM AUTHOR]

Ultrasonication‐assisted liquid exfoliation of layered materials is widely used to produce a large number of 2D nanosheets due to its simplicity, universality, and mass production. Here, the utility of ultrasonication is extended from liquid exfoliation to seed screening in the case of layered GeSe and GeS. It is found that the ultrasonic stripping force can also be used to selectively remove the lying seeds interacting with substrate through weak van der Waals (vdW) forces while retaining the standing seeds connected with substrate via tightly covalent bonds. The standing seeds then induce the growth of 2D crystal‐structural films with standing orientation. This thereby enables efficient carrier transport within covalently bonded layers, instead of poor transport between layers held together by vdW forces. The resulting standing‐oriented GeSe films exhibit a 21‐times increase in carrier mobility compared to lying‐oriented films. As a result, this study demonstrates the highest power conversion efficiencies of 6.1% and 10.5% under AM1.5G 1‐ and 0.01‐sun illumination reported for GeSe solar cells, respectively. [ABSTRACT FROM AUTHOR]

Anion-exchange membrane fuel cells and Zn–air batteries based on non-Pt group metal catalysts typically suffer from sluggish cathodic oxygen reduction. Designing advanced catalyst architectures to improve the catalyst's oxygen reduction activity and boosting the accessible site density by increasing metal loading and site utilization are potential ways to achieve high device performances. Herein, we report an interfacial assembly strategy to achieve binary single-atomic Fe/Co-Nx with high mass loadings through constructing a nanocage structure and concentrating high-density accessible binary single-atomic Fe/Co–Nx sites in a porous shell. The prepared FeCo-NCH features metal loading with a single-atomic distribution as high as 7.9 wt% and an accessible site density of around 7.6 × 1019 sites g−1, surpassing most reported M–Nx catalysts. In anion exchange membrane fuel cells and zinc–air batteries, the FeCo-NCH material delivers peak power densities of 569.0 or 414.5 mW cm−2, 3.4 or 2.8 times higher than control devices assembled with FeCo-NC. These results suggest that the present strategy for promoting catalytic site utilization offers new possibilities for exploring efficient low-cost electrocatalysts to boost the performance of various energy devices. An interfacial assembly strategy was developed to construct single-atom binary Fe/Co-Nx sites with a high accessible site density of 7.6 × 1019 sites per gram which results in increased power densities in fuel cells and Zn/air batteries. [ABSTRACT FROM AUTHOR]

Metallic conductive 1T phase molybdenum sulfide (MoS2) has been identified as promising anode for sodium ion (Na+) batteries, but its metastable feature makes it difficult to obtain and its restacking during the charge/discharge processing result in part capacity reversibility. Herein, a synergetic effect of atomic‐interface engineering is employed for constructing 2H‐MoS2 layers assembled on single atomically dispersed Fe−N−C (SA Fe−N−C) anode material that boosts its reversible capacity. The work‐function‐driven‐electron transfer occurs from SA Fe−N−C to 2H‐MoS2 via the Fe−S bonds, which enhances the adsorption of Na+ by 2H‐MoS2, and lays the foundation for the sodiation process. A phase transfer from 2H to 1T/2H MoS2 with the ferromagnetic spin‐polarization of SA Fe−N−C occurs during the sodiation/desodiation process, which significantly enhances the Na+ storage kinetics, and thus the 1T/2H MoS2/SA Fe−N−C display a high electronic conductivity and a fast Na+ diffusion rate. [ABSTRACT FROM AUTHOR]

As an isostructural analog of black phosphorus, GeSe has attracted considerable attention recently due to its intriguing in-plane anisotropic optical, vibrational, and electrical properties stemming from the low-symmetry two-dimensional crystal structure. However, there has been no report about the anisotropy tuning of GeSe, hampering its further applications in optoelectronics and electronics. Here, we systematically investigate the change of electronic properties of the bilayer GeSe with different stacked crystal structures under strain through first-principles calculation. Notably, the anisotropy of electron effective mass can be controlled and even rotated by 90° in a slipping process of one crystallographic period along the armchair direction. These plentiful strain-engineering properties of the bilayer GeSe would render it useful for the exploration of novel GeSe-based optoelectronic and electronics applications. [ABSTRACT FROM AUTHOR]