Simultaneous Enhancement of the Luminescence Intensity and Stability of Deep-Red CsPbI₃ Perovskite Quantum Dots Achieved by a Doping Strategy

Abstract

The phase instability of CsPbI3 perovskite quantum dots (PQDs) restricts their practical applications due to the easy conversion from the luminescent cubic phase to the non-luminescent orthorhombic phase. The elemental doping route has been regarded as one of the most effective strategies to achieve high-quality PQDs-based phosphors. Herein, a stoichiometric amount of nickel chloride (NiCl2) has been effectively doped into the CsPbI3 lattice. The incorporation of Ni2+ ions has little effect on the crystal phase, structure, and morphology of the CsPbI3 PQDs but greatly influences their luminescence properties. The Ni2+ doping not only improves the luminescence performance but also greatly enhances the stability against temperature, storage time, and polar solvent. The formation process and luminescence and stability improvement mechanisms have been discussed. Moreover, the influence of a series of other metal chlorides (KCl, NaCl, MgCl2, ZnCl2, SnCl2, and CaCl2) on the luminescence performance of CsPbI3 PQDs has been systematically investigated, revealing that the luminescence intensity increases by introducing CaCl2, SnCl2, or ZnCl2 but decreases after doping MgCl2, NaCl, or KCl into the CsPbI3 lattice. The as-proposed doping strategy may have a significant impact on tackling the intrinsic instability of all-inorganic CsPbX3 PQDs, shedding light on their future applications in light-emitting diode (LED) devices and solid-state lighting.

Mn2+-doping enables improved crystallization of CsPbI3 quantum dots for efficient deep-red light-emitting diodes

“…Li et al 8 reported that Zn 2+ -doped CsPbI 3 QDs exhibited a 120% increase in PLQY compared to undoped counterparts and the EQE of target PeLEDs increased from 7.5% to 14.6%. Wang et al 9 reported that the luminescence performance of the CsPbI 3 QDs changes evidently after doping the Ni 2+ and the PLQY of CsPbI 3 QDs increased from 68.7% to 86.6%. Lu et al 10 improved the PLQY and fluorescence lifetime of CsPbI 3 QDs (∼690 nm) with Ag + doping.…”