Thickness-Dependent Photoluminescence Properties of Mn-Doped CsPbBr<sub>3</sub> Perovskite Nanoplatelets Synthesized at Room Temperature
Zhaolun Yang, Xi Yuan, Yusheng Song, Mingyan Chen, Ke Xing, Sheng Cao, Jinju Zheng, Jialong Zhao
Abstract
Mn-doped CsPbBr 3 perovskite nanoplatelets (NPLs) with multicolor emission have very promising applications in light-emitting devices. However, the effects of NPL thickness on the Mn 2+ luminescence properties remain to be investigated. Herein, a series of Mn-doped CsPbBr 3 NPLs and nanocubes with different Mn/Pb molar ratios were synthesized by a supersaturated crystallization method at room temperature. The incorporation of Mn 2+ ions into CsPbBr 3 perovskites is attributed to the formation of the L 2 [Pb 1– x Mn x ]Br 4 intermediate structure in the precursor. The excitonic peak is tuned from 437 to 488 nm and the morphology evolves from NPLs to nanocubes with an increasing Mn 2+ ion doping concentration due to the excess Br – from MnBr 2 . The photoluminescence quantum yields (PL QYs) of NPLs/nanocubes were greatly enhanced, achieving the maximum PL QYs of 88.7% at the Mn/Pb molar ratio of 3/1. The PL lifetime of Mn 2+ emission is tuned from 0.19 to 0.44 ms due to the passivation of defect states and morphology transformation. Temperature-dependent steady-state and time-resolved PL spectra revealed that deep defect states in the NPLs/nanocubes were significantly reduced as the thickness increased. The Mn-doped CsPbBr 3 NPLs/nanocubes show great potential for application in white light-emitting diodes.