A strategy for boosting luminescence in lead-free double perovskites via passivation-induced surface engineering

Double perovskite materials exhibit great potential in optoelectronic applications due to their unique structure and excellent properties, with luminescence intensity enhancement being a major focus in luminescent material research. In this study, we report the passivation of double perovskite Cs 2 AgBi 0.2 In 0.8 Cl 6 using dimethyl sulfoxide (DMSO) as a passivating agent, achieving a significant enhancement in luminescence intensity. We observed increased luminescence intensity and prolonged fluorescence lifetime in the samples. Our study shows that when using DMSO as a passivator, S element in DMSO will combine with the surface metal ions (Ag + , In 3+ , or Bi 3+ ) of the samples to form ligand bonds and fill the surface Cl vacancies, thereby eliminating the surface defect states and suppressing non-radiative recombination. This promotes radiative recombination pathways. Consequently, the fluorescence lifetime is prolonged and the luminescence intensity is increased. Our work provides a feasible strategy for boosting luminescence in double perovskite materials.