A systematic strategy for effectively engineering the charge extraction in inverted structured perovskite solar cells based on CH₃NH₃PbI_3−xCl_xis provided. An optimized power conversion efficiency of 20.5% is realized.

The unique properties and structures of metal halide perovskite materials desired for a variety of photocatalytic applications in water splitting, CO ₂ reduction, pollutant degradation, and organic synthesis.

Polymer solar cells have shown good prospect for development due to their advantages of low-cost, light-weight, solution processable fabrication, and mechanical flexibility. Their compatibility with the industrial roll-to-roll manufacturing process makes it superior to other kind of solar cells. Normally, indium tin oxide (ITO) is adopted as the transparent electrode in polymer solar cells, which combines good conductivity and transparency. However, some intrinsic weaknesses of ITO restrict its large scale applications in the future, including a high fabrication price using high temperature vacuum deposition method, scarcity of indium, brittleness and scaling up of resistance with the increase of area. Some substitutes to ITO have emerged in recent years, which can be used in flexible polymer solar cells. This article provides the review on recent progress using other transparent electrodes, including carbon nanotubes, graphene, metal nanowires and nanogrids, conductive polymer, and some other electrodes. Device stability is also discussed briefly.

Though mixed cation hybrid organic–inorganic perovskite materials are of promise due to the high efficiency and long-term stability of the corresponding devices, a fundamental understanding on the function of the mixed cation system is still unclear. Herein, we systematically investigate the roles of the Cs cation and Cl anion in inverted structure perovskite solar cells based on Cs_xFA_0.2MA_0.8−xPb(I_1−yCl_y)₃. For the role of Cs, we observe that an appropriate amount of Cs in the film could improve the crystal quality of the film and optimize the energy band alignment of the device, thus reducing non-radiative recombination and promoting the charge transport efficiently. The presence of Cl with a suitable concentration also possesses these functions. More importantly, the two limitations for the application of the devices, hysteresis and performance instability, could also be addressed to some extent. Thus a high power conversion efficiency of 20.31% has been realized and a universal method for constructing highly-efficient perovskite solar cells has been provided.

Ag ₂ S/CdS heterojunction exhibits excellent photocatalytic H ₂ evolution performances, due to the highly effective separation and migration of charges.