Tunable dual emission in Mn ²⁺ -doped CsPbX ₃ (X = Cl, Br) quantum dots for high efficiency white light-emitting diodes

Abstract Doping of Mn ²⁺ into semiconductor nanocrystals has been demonstrated to endow them with novel electronic, optical and magnetic functionalities. In this paper, Mn-doped CsPbX ₃ (X = Br, Cl) quantum dots (QDs) were synthesized at room temperature via a facile strategy by introducing dimethyl sulfoxide (DMSO)-MnBr ₂ /PbX ₂ composite as a precursor. The excitonic emission spectra of the as-obtained Mn-doped CsPbX ₃ QDs can be tuned from 517 nm to 418 nm by adjusting the ratio of PbBr ₂ /PbCl ₂ precisely, and the luminescence mechanism of the doped QDs is discussed in detail. Moreover, the highest photoluminescence quantum yield of the Mn ²⁺ emission achieves 36.7%, which is comparable with QDs prepared by the conventional hot-injection method. Depending on the ratios of PbPb ₂ /PbCl ₂ , the energy transfer rate from the band-edge to Mn ²⁺ excited state is in the range of 0.006–20.42 × 10 ⁷ s ⁻¹ . Furthermore, white light-emitting diodes (LEDs) were successfully fabricated by combining the as-prepared Mn-doped CsPbX ₃ QDs with commercial UV GaN chips, and the high luminous efficiency of the as-prepared white LEDs was developed to 55.9 lm W ⁻¹ . This work strongly supports the fact that Mn-doped CsPbX ₃ QDs are promising materials for application in lighting and displaying fields.