Construction and characterization of an inorganic–organic hybrid copper(i) iodide coordination polymer with semiconducting luminescence

Abstract

Inorganic–organic hybrid semiconductors based on copper(I) halide are intriguing luminescent materials possessing great prospects as rare-earth elements (REEs) free phosphors for use in solid-state lighting (SSL). However, it is still a great challenge to develop such hybrid semiconducting materials with high energy blue light emission and good thermal stability simultaneously. Here, we have synthesized a brand new, one-dimensional (1D) organic–inorganic semiconductor CuI-Pytz (Pytz = 4-(pyrid-2-yl)-1,2,4-triazole) using a solvent diffusion method, for which the structure was determined by single crystal X-ray diffraction (SCXRD) and shows great thermal stability and decomposition temperature up to 220 °C. At room temperature, this indirect band gap hybrid semiconductor shows a blue emission centered at 464 nm which was nearing deep blue light (<460 nm) with a band gap energy of 2.70 eV. In addition, we developed a simple method for large-scale synthesis of the microcrystal, which significantly enhances the possibility of widespread applications for CuI-Pytz. Both density functional theory calculations and experimental studies reveal that the blue light emission originates from the combination of metal-to-ligand charge transfer (MLCT) and halide-to-ligand charge transfer (XLCT). The good thermal stability and high energy blue light emission make this low-cost and easily available copper(I) halide hybrid semiconductor a potential candidate for use as rare-earth free phosphors.