Ether-Soluble Cu Nanoclusters as an Effective Precursor of High-Quality CuI Films for Optoelectronic Applications.

An effective strategy is developed to synthesize high-nuclearity Cu clusters, [Cu (RCOO) (C≡CtBu) Cl H ] (Cu ), which is the largest Cu /Cu cluster reported to date. Cu powder and Ph SiH are employed as the reducing agents in the synthesis. As revealed by single-crystal diffraction, Cu is arranged as a four-concentric-shell Cu @Cu Cl @Cu @Cu structure, possessing an atomic arrangement of concentric M icosahedral and M dodecahedral shells which popularly occurs in Au/Ag nanoclusters. Surprisingly, Cu can be dissolved in diethyl ether and spin coated to form uniform nanoclusters film on organolead halide perovskite. The cluster film can subsequently be converted into high-quality CuI film via in situ iodination at room temperature. The as-fabricated CuI film is an excellent hole-transport layer for fabricating highly stable CuI-based perovskite solar cells (PSCs) with 14.3 % of efficiency.