Synthesis and DFT calculation of germanium halide perovskites with high luminescent stability, and their applications in WLEDs and indoor photovoltaics

Abstract

Addressing environmental pollution by entirely substituting lead is a significant concern in the field of perovskite optoelectronic devices. In this study, we used density functional theory to predict the structure and properties of the lead-free compound CsGeBr3, followed by its successful experimental synthesis. CsGeBr3 demonstrated the capability to emit white light and exhibited notable stability under UV radiation. Moreover, when combined with red-emitting MOF:Eu3+ phosphors, CsGeBr3 was effectively used to fabricate white light-emitting diode (WLED) devices. These devices exhibited a commendable color rendering index (CRI) of 92 and a correlated color temperature (CCT) of 3020 K. Furthermore, these light-emitting diode (LED) devices demonstrated their capacity to efficiently stimulate silicon solar cells, resulting in impressive photoelectric performance. We observed an increase in the open-circuit voltage, short-circuit current density, and cell impedance as the LED operating voltage increased, while the fill factor remained relatively unchanged. Given these beneficial properties, we strongly believe that lead-free CsGeBr3 holds promising potential for further research and development in the fields of WLEDs and indoor photovoltaics.