Efficient and High-Radiance Silicon-Based Perovskite Light-Emitting Diodes through Phase Segregation Control

Silicon-based perovskite light-emitting diodes (PeLEDs) have exhibited significant promise as high-radiance light sources due to the substantial thermal conductivity of silicon substrates that facilitate efficient Joule heat dissipation. However, the inherent instability of the commonly employed MA-based perovskite composition significantly hampered the performance of Si-based PeLEDs that rely on them. In this study, we opt for FAPbI(3)-based perovskite as the emission layer in the preparation of Si-based PeLEDs. Our investigation reveals that the introduction of a small amount of cesium cations and bromine anions, aimed at stabilizing the alpha-FAPbI(3) phase, leads to the segregation of the delta-CsPbI3 phase that creates a type I heterojunction with alpha-FAPbI(3). The resulting carrier confinement effect enhances radiative recombination, giving rise to a higher photoluminescence (PL) quantum yield and longer PL lifetime as compared to samples without phase segregation. Consequently, the optimized silicon-based PeLEDs achieve a remarkable external quantum efficiency (EQE) of 20.5%, outperforming the unitary phase-based ones by 1.6-folds. Furthermore, a microhole structure is adopted to enhance the performance of the devices under large injection, achieving a high radiance of 454.5 mW cm(-2) at 6.3 A cm(-2). Our results underscore the promising future of these devices in advanced optoelectronic applications, particularly under intense excitation.