Surface Engineering Studies on CsPbBr₃ Perovskites Quantum Dots for Optoelectronic Applications

Lead halide perovskite quantum dots have been considered as the most promising materials for next-generation optoelectronics because of their high light absorption, narrow emission, and excellent photophysical and optoelectronic properties. Organic ligands with long hydrocarbon chains used as ligands in quantum dot synthesis should be exchanged to short organic/inorganic ligands for improving the charge transporting in optoelectronic device applications. However, previous research related to surface ligand exchange for solar cell application have been largely focused on iodide-based CsPbI₃ perovskite quantum dots so far. For various solar cell applications such as tandem solar cell and Building-integrated photovoltaics (BIPVs), ligand exchange studies on bromide- and chloride-based perovskite quantum dots should be performed. Herein, we demonstrate that surface ligand exchange studies of green-emitting CsPbBr₃ perovskite quantum dots, utilizing several materials such as NaOAc. Improved charge transporting property within CsPbBr₃ perovskite quantum dot thin films contribute to the electroluminescent solar cell applications with high open-circuit voltage of 1.6 V and power conversion efficiency of 3.9 %. Also, quantum dot light-emitting diodes with synthesized CsPbBr₃ perovskite quantum dots was fabricated via interfacial engineering, showing 6.5% of EQE and 22.5 cd/A of current efficiency.