Organic-inorganic lead halide perovskite solar cells (PVSCs), as a competing technology with traditional inorganic solar cells, have now realized a high power conversion efficiency (PCE) of 22.1%. In PVSCs, interfacial carrier recombination is one of the dominant energy-loss mechanisms, which also results in the simultaneous loss of potential efficiency. In this work, for planar inverted PVSCs, the carrier recombination is dominated by the dopant concentration in the p-doped hole transport layers (HTLs), since the F4-TCNQ dopant induces more charge traps and electronic transmission channels, thus leading to a decrease in open-circuit voltages (V ). This issue is efficiently overcome by inserting a thin insulating polymer layer (poly(methyl methacrylate) or polystyrene) as a passivation layer with an appropriate thickness, which allows for increases in the V without significantly sacrificing the fill factor. It is believed that the passivation layer attributes to the passivation of interfacial recombination and the suppression of current leakage at the perovskite/HTL interface. By manipulating this interfacial passivation technique, a high PCE of 20.3% is achieved without hysteresis. Consequently, this versatile interfacial passivation methodology is highly useful for further improving the performance of planar inverted PVSCs.

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Three-dimensional (3-D) structures have triggered tremendous interest for thin-film solar cells since they can dramatically reduce the material usage and incident light reflection. However, the high aspect ratio feature of some 3-D structures leads to deterioration of internal electric field and carrier collection capability, which reduces device power conversion efficiency (PCE). Here, we report high performance flexible thin-film amorphous silicon solar cells with a unique and effective light trapping scheme. In this device structure, a polymer nanopillar membrane is attached on top of a device, which benefits broadband and omnidirectional performances, and a 3-D nanostructure with shallow dent arrays underneath serves as a back reflector on flexible titanium (Ti) foil resulting in an increased optical path length by exciting hybrid optical modes. The efficient light management results in 42.7% and 41.7% remarkable improvements of short-circuit current density and overall efficiency, respectively. Meanwhile, an excellent flexibility has been achieved as PCE remains 97.6% of the initial efficiency even after 10 000 bending cycles. This unique device structure can also be duplicated for other flexible photovoltaic devices based on different active materials such as CdTe, Cu(In,Ga)Se2 (CIGS), organohalide lead perovskites, and so forth.

Metal–inorganic semiconductor–metal photodetectors (MSM‐PDs) have received great attention in many areas, such as optical fiber communication, sensing, missile guidance, etc., due to their inherent merits of high speed, high sensitivity, and easy integration. This review focuses on MSM‐PDs with the semiconductor layer made of inorganic materials including traditional semiconductors (such as GaAs and Si), the third‐generation wide bandgap semiconductors (such as GaN, ZnO, and SiC), as well as several emerging semiconductors (such as perovskites and 2D materials). First, the basic structures of MSM‐PDs, including the planar and vertical configurations, are presented. Then, their working principles of MSM‐PDs are discussed. Subsequently, the research progresses on MSM‐PDs consisting of different photosensitive semiconductor materials are described in detail. Additionally, the efforts to optimize MSM‐PDs from the aspects of dark current, response speed, responsivity, spectral adjustment, etc., are also introduced. Finally, the review is concluded with the perspectives of MSM‐PDs from the authors’ vision.

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