While self-healing is considered a promising strategy to achieve long-term stability for oxygen evolution reaction (OER) catalysts, this strategy remains a challenge for OER catalysts working in highly alkaline conditions. The self-healing of the OER-active nickel iron layered double hydroxides (NiFe-LDH) has not been successful due to irreversible leaching of Fe catalytic centers. Here, we investigate the introduction of cobalt (Co) into the NiFe-LDH as a promoter for in situ Fe redeposition. An active borate-intercalated NiCoFe-LDH catalyst is synthesized using electrodeposition and shows no degradation after OER tests at 10 mA cm−2 at pH 14 for 1000 h, demonstrating its self-healing ability under harsh OER conditions. Importantly, the presence of both ferrous ions and borate ions in the electrolyte is found to be crucial to the catalyst’s self-healing. Furthermore, the implementation of this catalyst in photoelectrochemical devices is demonstrated with an integrated silicon photoanode. The self-healing mechanism leads to a self-limiting catalyst thickness, which is ideal for integration with photoelectrodes since redeposition is not accompanied by increased parasitic light absorption.
Organic-free perovskite solar cells
(PSCs) have been considered
as the most promising candidate for achieving long-term stability.
Here, we demonstrate an organic-free PSC consisting of inorganic CsPbI2Br perovskite, nickel oxide hole transport layer, and niobium
oxide electron transport layer. A maximum power conversion efficiency
(PCE) of 11.20% is achieved with an active area of 5 cm2, and it increases to 14.11% with smaller area. More importantly,
the organic-free PSCs show excellent thermal stability with PCE remaining
above 98% of its initial value when heated at 100 °C for 150
min. Postannealing at a proper temperature further increases its maximum
PCE to 14.45%, which is the highest among any reported all-inorganic
PSCs with a p-i-n structure. The enhanced performance of the postannealed
device is ascribed to the decreased trap-state density and improved
interface charge-transfer properties. These results demonstrated that
this novel organic-free device architecture can be employed to fabricate
efficient and stable PSCs for large-scale manufacturing.
B-site doping of organic−inorganic perovskites is an effective way to improve its optoelectronic properties; however, it is rarely reported for perovskite single crystals. Here, we report the B-site doping of MAPbBr 3 single crystals with erbium (Er) via a simple antisolvent vapor-assisted crystallization method. The Erdoped MAPbBr 3 single crystal exhibits significantly enhanced photoluminescence (PL) and photoconductivity compared with the undoped sample. Low-temperature PL spectroscopy reveals that Er-doping creates a shallow acceptor level inside the band gap of MAPbBr 3 , which contributes to significantly enhanced PL emission because of bound excitons. Furthermore, Er-doping also effectively lowers the deep trap density and improves the conductivity and mobility of the single crystal. Consequently, the Er-doped MAPbBr 3 single crystal photodetector shows responsivity and external quantum efficiency approximately 5 times higher than those of the undoped device. The effective improvement of optoelectronic properties of the MAPbBr 3 single crystal by Er-doping may benefit a wide range of devices including photodetectors, light-emitting diodes, and lasers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.