Oxygen reduction reaction (ORR) is of paramount importance in polymer electrolyte membrane fuel cells due to its sluggish kinetics. In this work, a plasmon-induced hot electrons enhancement method is introduced to enhance ORR property of the silver (Ag)-based electrocatalysts. Three types of Ag nanostructures with differently localized surface plasmon resonances have been used as electrocatalysts. The thermal effect of plasmonic-enhanced ORR can be minimized in our work by using graphene as the support of Ag nanoparticles. By tuning the resonance positions and laser power, the enhancement of ORR properties of Ag catalysts has been optimized. Among these catalysts, Ag nanotriangles after excitation show the highest mass activity and reach 0.086 mA/μgAg at 0.8 V, which is almost 17 times that of a commercial Pt/C catalyst after the price is accounted. Our results demonstrate that the hot electrons generated from surface plasmon resonance can be utilized for electrochemical reaction, and tuning the resonance positions by light is a promising and viable approach to boost electrochemical reactions.

The non‐cubic antimony chalcogenides, i.e., Sb2Se3, formed by quasi‐one‐dimensional ribbons can enhance light absorption and carrier transport by tuning the ribbon direction using the close‐space sublimation (CSS) deposition. The improved device performance is found to be associated with the ribbon direction, which was investigated with theoretical calculation and experimental optical measurement in the Sb2Se3 films and devices. Decent device efficiency could be achieved when the ribbons were tuned to be as normal to the substrate as possible. The substrate temperature and film thickness are critical for the fine‐tuning of ribbon orientations during the CSS deposition. Our results show that [211]‐preferred orientation leads to the minimum series resistance and highest light absorbance in the device. This observation demonstrates that Sb2Se3‐like quasi‐one‐dimensional materials with van der Waals boundaries can achieve scalable production at low cost and hold great potential for next‐generation solar cell using the recently developed vapor transport deposition technology.

Antimony chalcogenide Sb2Se3 is an emerging photovoltaic absorber due to its appropriate bandgap (≈1.1 eV), high absorption coefficient (>105 cm−1), suitable p‐type conductivity, low toxicity, earth abundance, and excellent stability. However, the stringent growth condition and low photovoltage limit its power conversion efficiency (PCE). Herein, via a combined theoretical and experimental study, interface engineering via an oxygenated cadmium sulfide (CdS) window layer (CdS:O) is found to be an effective approach to improve the device performance of CdS:O/Sb2Se3 solar cells. The sputtered oxygenated CdS:O window layer can be used to replace conventional chemical‐bath‐deposited CdS window layer in the Sb2Se3 devices. The best PCE of 7.01% is demonstrated in the superstrate configuration of fluorine‐doped SnO2/CdS:O/Sb2Se3/graphite with a high open‐circuit voltage of 0.432 V, where Sb2Se3 is fabricated using the close space sublimation technique. The interfacial diffusion between Sb2Se3 and sputtered CdS:O is significantly suppressed by introducing oxygen at the interface, which prevents Cd diffusion and the formation of Cd interstitials. Combined device physics characterizations and theoretical calculations reveal that oxygen in the CdS:O/Sb2Se3 interface can increase depletion region, built‐in voltage, and reduce interfacial recombination. These findings provide the guidance to optimize quasi‐one‐dimensional non‐cubic earth‐abundant chalcogenide photovoltaic devices through interface engineering.

Transformations between different atomic configurations of a material oftentimes bring about dramatic changes in functional properties as a result of the simultaneous alteration of both atomistic and electronic structure. Transformation barriers between polytypes can be tuned through compositional modification, generally in an immutable manner. Continuous, stimulusdriven modulation of phase stabilities remains a significant challenge. Utilizing the metal−insulator transition of VO 2 , we exemplify that mobile dopants weakly coupled to the crystal lattice provide a means of imbuing a reversible and dynamical modulation of the phase transformation. Remarkably, we observe a time-and temperature-dependent evolution of the relative phase stabilities of the M 1 and R phases of VO 2 in an "hourglass" fashion through the relaxation of interstitial boron species, corresponding to a 50 °C modulation of the transition temperature achieved within the same compound. The material functions as both a chronometer and a thermometer and is "reset" by the phase transition. Materials possessing memory of thermal history hold promise for applications such as neuromorphic computing, atomic clocks, thermometry, and sensing.

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