2018年5期 电子期刊

研究了不同Mn/Pb量比的Mn掺杂CsPbCl₃（Mn：CsPbCl₃）钙钛矿量子点的发光性质。Mn/Pb的量比增加引起的Mn²⁺发光峰的红移，被认为是来源于高浓度Mn²⁺掺杂下的Mn²⁺-Mn²⁺对。进一步研究了Mn：CsPbCl₃量子点的发光效率与Mn/Pb的量比之间的关系，发现随着量比达到5：1时，其发光效率明显下降。这种发光效率下降是由于Mn掺杂浓度引起的发光猝灭。Mn：CsPbCl₃量子点的变温发光光谱证实，随着温度的升高，Mn离子发光峰蓝移，线宽加宽，但其发光强度明显增加。

Photoluminescence Properties of Mn Doped CsPbCl3 Perovskite Quantum Dots

Photoluminescence(PL) properties of Mn doped CsPbCl₃ (Mn:CsPbCl₃) perovskite quantum dots(QDs) with various Mn/Pb molar ratios were studied. Two emission bands peaked at around 400 nm and 600 nm, respectively, were observed in Mn:CsPbCl₃ QDs at room temperature. The PL intensity of Mn ion emission in the Mn:CsPbCl₃ QDs was significantly enhanced with respect to the band edge exciton emission as Mn/Pb molar ratio increased from 0.5:1 to 5:1. Both the exciton absorption and emission bands in the doped QDs shifted to the blue, which was consistent with the reduction of the QD size. The red shift of Mn²⁺ emission band with increasing the molar ratio was considered to result from the formation of Mn²⁺-Mn²⁺ pairs in the doped QDs due to high concentration Mn doping. Further, the PL quantum efficiency of Mn:CsPbCl₃ QDs as a function of Mn/Pb molar ratio was studied in detail. It is found that the PL quantum yield of Mn²⁺ gradually increases with the increasing of Mn/Pb molar ratio. The maximum PL quantum yield reaches 62% as Mn/Pb molar ratio is 2:1. The PL quantum yield drops continually with the increasing of Mn/Pb molar ratio to 5:1. The reduction of PL quantum yield at high concentration Mn doping is related to Mn doping concentration-induced PL quenching due to the formation of Mn²⁺-Mn²⁺ pairs. The temperature-dependence of PL spectra in Mn:CsPbCl₃ QDs demonstrates that Mn²⁺ emission band shifts to the blue and the emission width is broadened, while PL intensity increases, which is in contrast to Ⅱ-Ⅵ semiconductor QDs.