Robust and Highly Conductive Water-Stable Copper Iodide-Based Hybrid Single Crystals

High conductivity, carrier mobility as well as long diffusion length are critical for highly efficient solar cells. Here, we report new types of crystalline inorganic–organic hybrid semiconductors, 2D-Cu2I2(L) [L = benzo[c][1,2,5]thiadiazole (bs) and benzo[c][1,2,5] selenadiazole (bse)], composed of one-dimensional (1D) copper iodide staircase-like chain and benzodiazole-based ligands. These compounds possess narrow and tunable band gaps and high conductivity. High-quality large single crystals of 2D-Cu2I2(bse) were grown and used to evaluate the charge transport properties of the material. State-of-the-art time-resolved microwave conductivity (TRMC) techniques were used to investigate the charge carrier dynamics, from which a high conductivity of 2 × 10–4 S/cm, a carrier mobility of ∼1 cm2 V–1 s–1, a maximum doping/carrier density of 2 ± 1 × 1015 cm–3, and a diffusion length of ∼0.17 μm were obtained. The excellent water/chemical stability combined with high conductivity makes this I–VII-based hybrid material family promising candidates for potential optoelectronic applications.