Tunable cathodoluminescence over the entire visible window from all-inorganic perovskite CsPbX3 1D architecture

Abstract

With exceptional attributes like high carrier mobility, long diffusion lengths and tunable spectral absorption window, all-inorganic perovskites have shown the potential to be the most extraordinary and market competitive optoelectronic material, making their facile realization and detailed photophysical analysis necessary. Going beyond well reported perovskite quantum dots, all-inorganic cesium lead halide (CsPbX₃, X = Cl, Br or I) perovskite rods have been realized, both in pure as well as mixed halide phases, via a facile, environmentally benign, room temperature and solution based protocol. Using a series of halide precursor alterations in this general synthesis protocol, we have tailored the chemical and optical features of the rod in a subtle manner. The highlights of this synthesis protocol are the zero thermal budget and the ability to bulk produce and have tailor made control over exact phase formation. Pure phase halide perovskite rods were crystallized in the orthorhombic phase. These rods exhibit a strong intense cathodoluminescence emission which can be tuned over the entire visible range by varying the halide composition. Besides cathodoluminescence, these single crystalline perovskite rods also exhibited wavelength tunable photoluminescence. In addition to the pure phase synthesis of all of the inorganic perovskite forms, the halide induced structural features were also correlated with their optical properties in detail. Halide substituted band gap engineering results were further corroborated computationally via density functional analysis of these perovskites. Our preparation method provides a facile and adaptable pathway to rationally control the different forms of CsPbX₃ perovskite, which may lead to opportunities for applications, such as in lasing, light-emitting diodes, solar cells, photo detectors etc.