Lead-Based Metal-Organic-Framework Engineering Enables the Efficiency of Pure-Red Perovskite CsPbI3 Quantum Dot-Based
Weichuang Guo1, Yuzhu Xu1, Jisong Yao1
1Key Laboratory of Materials Physics of Ministry of Education, Laboratory of Zhongyuan Light, School of Physics, Zhengzhou University, Zhengzhou, China.
None:
CsPbI3 quantum dots (QDs) are promising for meeting the Rec. 2020 specified red emission but still face the issue of color impurity caused by QD polydispersity. Here we develop a facile approach to synthesize nearly monodisperse and sub-5 nm-sized CsPbI3 QDs by regulating QD growth using a lead-based metal-organic framework (Pb-MOF). The multidentate ligands, 2-mercapto-4-methyl-5-thiazoleaceticacid (MMA), released from the Pb-MOFs strongly adsorb onto the QD surface through double-end coordination with exposed Pb2+, effectively reducing non-radiative recombination centers. Moreover, the QDs synthesized with Pb-MOFs show a full width at half maximum (FWHM) of 31 nm and high conductivity (1.3 × 10-4 S m-1), which are about 10 nm narrower, and 2.5-fold higher than that of the control QDs, respectively. As a result, the QD-based light-emitting diodes (QLEDs) based on CsPbI3 QDs emits at 634 nm with a CIE coordinate of (0.70, 0.30), covering 98.5% of the Rec. 2020 standard in the CIE 1931. Meanwhile, the QLEDs show a high external quantum efficiency of 30.8% and a long operational half-lifetime (T50) exceeding 140 h at an initial luminance of 100 cd m-2, ranking as one of the most efficient and stable pure-red perovskite QLEDs reported to date.
