Enhancing energy channel and carriers recycling in sky-blue perovskite light-emitting diodes via a fluorescent fortifier

Metal halide perovskite materials are renowned for their exceptional photoelectric properties, holding immense promise as next-generation luminescent materials. However, challenges, such as inferior film morphology, multidimensional phase coexistence, and energy level barrier hindrance, result in carrier transport imbalance and poor confinement. The presence of numerous defects in the light-emitting layer (EML) or at the interface leads to auger recombination, hindering the attainment of high-efficiency and stable devices. To address these issues, herein, we introduce a fluorescent material named t-DABNA-dtB in a hole transport layer (HTL) as a carrier catcher, leveraging the Förster channel to enhance energy and carrier utilization. Moreover, the reduction in energy level barriers between HTL and EML ensures balanced carrier transport within the EML and effectively suppresses trap-induced non-radiative losses. Consequently, the diminished density of defect states effectively curbs luminescence quenching, leading to enhanced device stability.