Hybrid organic–inorganic lead bromide perovskite supercrystals self-assembled with l-cysteine and their good luminescence properties

Abstract

The introduction of functional ligands that are beneficial for the assembly of perovskite nanocrystals (PNCs), has opened up new avenues for the fabrication of highly efficient optoelectronic and photovoltaic devices. In this work, self-assembled organic–inorganic hybrid lead bromide perovskite cubic supercrystals have been synthesized via a wet chemistry approach using trifunctional L-cysteine as capping ligands. These supercrystals were enhanced 6.9 times compared to discrete PNCs due to their absolute photoluminescence (PL) quantum yield and an observed PL lifetime of 642 ns as well as their good stability in protic solvents. These properties are attributed to synergistic effects among amino, carboxylic and sulfhydryl groups, which not only guide the self-assembly process by cross-linking but also protect the individual PNC from aggregation due to strong binding interactions between the L-cysteine ligands and the NCs. Furthermore, CH₃NH₃PbBr₃ supercrystals have been used in the fabrication of green perovskites and white light-emitting diodes with excellent performance. The facile crosslinking process using unique L-cysteine ligands is promising for rational design and controllable fabrication of functional perovskite-based materials for optoelectronics applications.