Polystyrene based perovskite light emitting diode

Abstract

Hybrid organic–inorganic semiconductors (HOIS) based on lead halides exhibit unique optoelectronic properties even at room temperature, immediately assigning these for potential applications as optical and active device materials, where most common applications have been light emitting diodes (LED), solar cell devices and X-ray detectors. In this work, a low cost and simple prototype single layer LED emitting green light under low voltage, is presented. The main advantage in this work's LED is that the active layer is based on a blend of low dimensional (LD) perovskites entrapped in a polystyrene film, never reported before. The HOIS blend is formed by the admixture of two-dimensional (2D) (C6H5CH2CH2NH3)2PbBr4, one dimensional (1D) CH3NH3CdBr3, while the blend's entrapment is afforded by mixing it with dissolved polystyrene powder. It is found that final composite contains a blend of quasi two-dimensional (quasi-2D) perovskites, that exhibits green luminescence and electroluminescence, assisted by energy funneling phenomena toward the blend's moiety with the smallest energy band gap. The addition of Cd++ is reported as a paradigm for several effects; its addition is not inhibiting the electroluminescence, while also polystyrene successfully prevents even cadmium halide's degradation by moisture. Moreover, successful doping of the LED active material portrays possibilities for enhancing perovskite-based devices, as it has been shown that cation dopants enhance the photoluminescence or transfer energy toward the dopant's light emission energy bands.