High brightness blue light-emitting diodes based on CsPb(Cl/Br)3 perovskite QDs with phenethylammonium chloridesynonym passivation.
All inorganic perovskite quantum dots (QDs) (CsPbX3, X=Cl, Br, I) have been applied on the light-emitting devices (LEDs) in recent years due to their excellent optical and optoelectronic properties. However, the blue-light emitting perovskite QD LEDs (PQD-LEDs) exhibit the poor performances comparing with their green- and red-light emitting counterparts. Herein, we fabricated the high performing blue-light emitting PQD-LED based on the phenethylammonium chloridesynonym (PEACl) modified CsPb(Cl/Br)3 QDs. Firstly, the PEA-CsPbCl3 QDs were synthesized by introducing the certain amounts of PEACl in the conventional hot-injection synthesis process. The merit of our synthesis lies in the fact that not only the Cl vacancies of CsPbCl3 QDs are efficiently modified by introducing the PEACl precursor, but also the partial long-chain organic ligands (OLA) capping on the surface of CsPbCl3 QDs are simultaneously replaced by the shorter PEACl chains. Consequently, the PEA-CsPbCl3 QDs emitted at 410 nm with the PLQY of 62.3% was achieved. Furthermore, to meet the requirement of display application, we exchange Cl- with Br- ions at room temperature to precisely control the blue emission in 460-470 nm spectral regions and with the maximum PLQY of 80.2% at 470 nm. Finally, the PQD-LEDs based on PEA-CsPb(Cl/Br)3 perovskite QDs emitted at 462, 465, 468 and 470 nm were fabricated. The PQD-LEDs exhitie the maximal EQE of 2.15% and luminance of 620 cd/m2, which provides a highest value of luminance for the PQD-LEDs in the blue spectral range that satisfying the practical display applications.