Enhancing the Luminescence Performance of Monodisperse Lead-Free Double Perovskite Cs₂AgBiBr₆ Nanocrystals Alloyed with Indium

Lead-free double perovskite nanocrystals (NCs) have garnered significant attention due to their ability to address the toxicity and instability issues associated with lead-based perovskite NCs. Herein, we have successfully synthesized a series of Cs2AgBiBr6 NCs with varying concentrations of In3+ alloying, achieved through a colloidal solution method. These NCs consistently exhibit a monodisperse, uniform cubic morphology. By meticulously adjusting the alloying concentration of In3+, we have significantly enhanced the luminescence performance of Cs2AgBiBr6 NCs, achieving a maximum photoluminescence quantum yield of 14.69% at the optimal In3+ alloying concentration. Simultaneously, the exciton lifetime was markedly extended 4.6 times, greatly enhancing carrier dynamics. Temperature-dependent photoluminescence spectroscopy analysis further confirms that postalloying with In3+, the NCs not only exhibit strong Coulombic forces and high thermal stability but also significantly reduce nonradiative transition processes. Moreover, density functional theory calculations reveal that In3+ alloying leads to a redistribution of charge density, profoundly affecting the electronic structure and subsequently enhancing the carrier mobility. Therefore, this study not only provides valuable insights into the role of In3+ alloying in enhancing the luminescence performance of double perovskite NCs but also opens up potential application prospects for optoelectronic devices in the future.