[6a-A404-1~11] 13.7 Nanostructures, quantum phenomena, and nano quantum devices

△ [6a-A404-6] High-efficiency perovskite quantum-dot light-emitting devices by
effective washing process and interfacial energy level alignment

〇Keigo Hoshi¹, Takayuki Chiba¹, Yong-Jin Pu¹, Yuya Takeda¹, Yukihiro Hayashi¹, Satoru Ohisa¹, Junji Kido¹ (1.Yamagata Univ.)

Keywords:quantum dots, washing process, light emiting device

All inorganic perovskites quantum dots (PeQDs) have attracted much attention for used in thin film display applications and solid-state lighting applications, owing to their narrow band emission with high photoluminescence quantum yields (PLQYs), color tunability, and solution processability. Here, we fabricated low-driving-voltage and high-efficiency CsPbBr₃ PeQDs light-emitting devices (PeQD-LEDs) using a PeQDs washing process with an ester solvent containing butyl acetate(AcOBu) to remove excess ligands from the PeQDs. The CsPbBr₃ PeQDs film washed with AcOBu exhibited a PLQY of 42%, and a narrow PL emission with a full width at half-maximum of 19 nm. We also demonstratedenergy level alignment of the PeQD-LED in order to achieve effective hole injection into PeQDs from the adjacent hole injection layer. The PeQD-LED with AcOBu washed PeQDs exhibited a maximum power efficiency of 31.7 lmW⁻¹ and EQE of 8.73%. Control of the interfacial PeQDs through ligand removal and energy level alignment in the device structure are promising methods for obtaining high PLQY in film state and high device efficiency.