Enhancement of Se solubility in organic solvents without the use of alkylphosphine ligands is the key for phosphine-free synthesis of selenide semiconductor nanocrystals (NCs). In this communication, we demonstrate the dissolution of elemental Se in oleylamine by alkylthiol reduction at room temperature, which generates soluble alkylammonium selenide. This Se precursor is highly reactive for hot-injection synthesis of selenide semiconductor NCs, such as Cu(2)ZnSnSe(4), Cu(InGa)Se(2), and CdSe. In the case of Cu(2)ZnSnSe(4), for example, the as-synthesized NCs possessed small size, high size monodispersity, strong absorbance in the visible region, and in particular a promising increase in photocurrent under AM1.5 illumination. The current preparation of the Se precursor is simple and convenient, which will promote the synthesis and practical applications of selenide NCs.

Tungsten oxide ͑WO 3 ͒ was inserted as an anode interfacial layer between the photoactive layer and top electrode in inverted polymer solar cells ͑PSCs͒ with nanocrystalline titanium dioxide as an electron selective layer. The device with WO 3 exhibited a remarkable improvement in power conversion efficiency compared with that without WO 3 , which indicated that WO 3 efficiently prevented the recombination of charge carriers at the organic/top electrode interface. The dependence of the device performances on WO 3 film thickness and different top metal electrodes was investigated. Transparent inverted PSCs with thermally evaporable Ag/ WO 3 as a transparent anode were also investigated when introducing a WO 3 buffer layer.

State‐of‐the‐art photodetectors which apply hybrid perovskite materials have emerged as powerful candidates for next‐generation light sensing. Among them, lead‐based ones are the most popular beyond doubt on account of their unique and superior optoelectronic properties. Nevertheless, trade‐off toward commercialization exists between nontoxicity and high performance, with the poor stability of lead‐based perovskites, indicating that it is indispensable to substitute lead with nontoxic element meanwhile bringing about a comparable figure of merit of photodetectors and relatively long‐term stability. Herein, recent advances in lead‐free perovskite photodetectors are reviewed, analyzing the principle while designing new materials and highlighting some remarkable progress, which are comparable, even superior, to lead‐based photodetectors. Furthermore, their potential strategy in optical communication, image sensing, narrowband photodetection, etc., is examined and a perspective on developing new materials and photodetectors with superior properties for more practical applications is provided.