High-Performance CsPbX3 Perovskite Quantum-Dot Light-Emitting Devices via Solid-State Ligand Exchange

Recently, all-inorganic perovskite quantum dots (PeQDs), CsPbX3 have become attractive because of their excellent optoelectronic properties and superior air/moisture stabilities compared with conventional organic–inorganic hybrid perovskites, and the application of CsPbX3 PeQDs to light-emitting devices (LEDs) has also become competitive. To enable the use of CsPbX3 PeQDs for thin-film-type perovskite quantum-dot LEDs (PeQLEDs), a paradox associated with the ligand property and surface passivation must be overcome during thin-film fabrication. A decline in the photoemission performance was observed at relatively low amounts of surface-passivating ligands, while the quality of the thin film deteriorated in the presence of excessive ligands. To address this conflict, in this study, the performance of PeQLEDs based on CsPbX3 fabricated by a novel method involving solid-state ligand exchange (SLE) with aromatic acid/amine was investigated. Using this strategy, most of the excess ligands were removed while pre...