Bright Blue Light Emission of Ni2+ ions doped CsPbClxBr3-x Perovskite Quantum Dots Enabling Efficient Light-Emitting Devices

摘要： In recent years, significant advances have been achieved in the red and green perovskite quantum dots（PQDs）based light-emitting diodes (LEDs). However, the performances of the blue perovskite LEDs are still seriously lagging behind that of the green and red counterparts. Herein, we successfully developed Ni2+ ions doped CsPbClxBr3-x PQDs through the room-temperature supersaturated recrystallization synthetic approach. We simultaneously realized the doping of various concentrations of Ni2+ cations, and modulated the Cl/Br element ratios through introducing different amount of NiCl2 solution in the reaction medium. By the synthetic method, not only the emission wavelength from 508 to 432 nm of Ni2+ ions doped CsPbClxBr3-x QDs was facially adjusted, but also the photoluminescence quantum yield (PLQY) of PQDs was greatly improved due to efficiently removing the defects of the PQDs. Thus, the blue emission at 470 nm with PLQY of 89% was achieved in 2.5% Ni2+ ions doped CsPbCl0.99Br2.01 QDs, which increased nearly three times over that of undoped CsPbClBr2 QDs, and was the highest for the CsPbX3 PQDs with blue emission that fulfilling the NTSC standards. Benefiting from the high luminous Ni2+ ions doped PQDs, the blue emitting LED at 470 nm was obtained, exhibiting an external quantum efficiency (EQE) of 2.4% and a maximum luminance of 612 cd/m2, which surpassed the best performance reported previously for the corresponding blue-emitting PQDs based LED.