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^-4S/cm, a carrier mobility of ∼1 cm²V^-1s^-1, a maximum doping/carrier density of 2 ± 1 × 10¹⁵cm^-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.