Delayed Fluorescence in Dual‐Doped Perovskite Nanocrystals: Insight into the Role of Dopants

This study investigates the photophysical behaviour of Mn/Fe and Mn/Sn co‐doped CsPbCl3 perovskite nanocrystals (NCs) to explore carrier dynamics and dopant interactions. Using gated photoluminescence (PL) and temperature‐dependent measurements, we elucidate the impact of dopant chemistry on exciton behaviour, focusing on vibrationally assisted delayed fluorescence (VADF) and energy transfer mechanisms. The efficiency of VADF is influenced by factors such as the bandgap, temperature, quantum confinement, and host composition. In Mn/Fe co‐doped NCs, Fe‐induced trap states introduce additional radiative pathways, resulting in a unique emission around 515 nm. In contrast, in Mn/Sn co‐doped NCs, Sn captures photoexcited carriers, preventing the VADF process and leading to non‐radiative decay. The findings provide key insights into dopant‐dopant interactions and the mechanisms governing carrier transfer, enhancing our understanding of these materials for future optoelectronic applications.