Boosting radiation of stacked halide layer for perovskite solar cells with efficiency over 25%

Although halide perovskite solar cells (PSCs) have shown tremendous progress in device performance, state-of-the-art PSCs are still far below the theoretical efficiency. To further reach the theoretical limit, it is essentially required to maximize radiative recombination in the full device stack. Here, we report that boosting radiation in the full device stack is an effective way for reaching the radiative limit of power conversion efficiency (PCE) by demonstrating the correlation between external photoluminescence quantum efficiency (PLQE) of the full device stack and PCE of the devices. We found that controlling the bottom charge transporting layer (CTL)/perovskite interface is a main factor to boost radiation in the full device stack. The device combined with the interface and bulk engineering exhibited an improved external PLQE of 15.57%, resulting in an improved PCE of over 25% (certified 25.06%) and almost 95% achievement rate of the radiative limit open-circuit voltage (V_oc).