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Perovskites have showed significant potential for the application in photodetectors due to their outstanding electrical and optical properties. Integrating two-dimensional (2D) materials with perovskites can make full use of the high carrier mobility of 2D materials and strong light absorption of perovskite to realize excellent optoelectrical properties. Here, we demonstrate a photodetector based on the WTe2/CsPbI3 heterostructure. The quenching and the shortened lifetime of photoluminescence (PL) for CsPbI3 perovskite confirms the efficient charge transfer at the WTe2/CsPbI3 heterojunction. After coupled with WTe2, the photoresponsivity of the CsPbI3 photodetector is improved by almost two orders of magnitude due to the high-gain photogating effect. The WTe2/CsPbI3 heterojunction photodetector reveals a large responsivity of 1157 A W−1 and a high detectivity of 2.1 × 1013 Jones. The results pave the way for the development of high-performance optoelectronic devices based on 2D materials/perovskite heterojunctions. [ABSTRACT FROM AUTHOR]

It is imperative to improve the quality of light absorber and reduce the charge‐carrier recombination for efficient perovskite solar cells (PSCs). Herein, a synergistic regulation strategy that combines the tailoring of crystallinity and construction of multilayer cascade charge transport layers (CTLs) for inverted CsPbI2Br solar cells is presented. The film quality of CsPbI2Br is well tuned via F− doping. In addition, gradient energy alignment between perovskite and CTLs, i.e., NiOx/Zn:CuGaO2/perovskite and perovskite/TiO2/PC61BM/ZnO, favors the charge transfer and depresses carrier recombination. Noticeably, the TiO2 interlayer with deep valence band maximum effectively blocks the hole back‐transfer from perovskite to PC61BM. These unique characteristics of the novel structured CsPbI2Br device give a champion power conversion efficiency (PCE) of 15.10% along with good thermal and operational stability. Moreover, the graded CTLs can be expanded to methylammonium‐free hybrid perovskite device (Eg = ≈1.76 eV) by delivering a PCE of 18.12%, showing great promise in tandem solar cells for use as top cell. [ABSTRACT FROM AUTHOR]

A novel non-noble perovskite-type Ce 1/3 NbO 3 electrocatalyst is proposed as a promising nitrogen rediction reaction by both theoretically prediction and experimentally confirmation. • A Ce 1/3 NbO 3 perovskite is proposed and exhibits a potential N 2 activation ability by the theoretical prediction. • Experimentally, the produced ammonia from the nitrogen reduction reaction (NRR) under such Ce 1/3 NbO 3 electrocatalyst is identified successfully by the electrochemical tests, confirming our theoretical prediction. • The detailed reaction mechanism calculations conclude that NRR proceed by the distal mechanism and the potential determining step is the hydrogenation of *NH 2. Herein, a novel Ce 1/3 NbO 3 perovskite is proposed as an efficient electrocatalyst to catalyze the nitrogen reduction reaction (NRR) at ambient conditions. Density functional theory calculations are firstly used to predict the potential N 2 activation ability of Ce 1/3 NbO 3 , and then, the Ce 1/3 NbO 3 with a flower-like porous structure is prepared by a hydrothermal process and post calcination. Electrochemical tests reveal that such catalyst achieves a high NRR performance with the Faradaic efficiency of 6.87% and NH 3 yield of 10.34 µg h−1 cm−2 at −0.8 V vs RHE in 0.1 M Na 2 SO 4 , keeping up with many electrocatalysts reported recently. The mechanistic studies disclose that Nb atom is favorable as the efficient active site for NRR by the distal pathway, and Ce atom synergistically enhances the charge transfer during the NRR process. Our work provides an important reference to the rational design of the promising electrocatalysts for NRR. [ABSTRACT FROM AUTHOR]