Cation‐Mediated Low‐Frequency Phonon Suppression in Lead‐free Manganese Halides for High‐efficiency Green Light‐emitting Diodes
Abstract
Abstract Lead halide perovskites (LHPs) have emerged as promising materials in optoelectronics, yet concerns over lead toxicity drive the search for lead‐free alternatives with efficient electroluminescence, especially in green‐emitting applications. Here, the photophysical functions of A‐site cations in manganese bromides are revealed, and design dimethylamino‐functionalized A‐site cations to modulate both phonon dynamics, film morphology, and energy level alignment, enabling unprecedented efficiency in solution‐processed green‐emitting lead‐free metal halide devices. Appropriately attaching of dimethylamino groups to benzene rings not only builds p– π conjugation that increases the rigidity of PPh 4 + A‐site cations, but also weakens hazardous van der Waals interaction, which suppresses A‐site related nonradiative recombination. Importantly, methyl groups in dimethylamino groups enhance the flexibility of the A‐site cation, which suppresses the formation of grain boundaries. Moreover, dimethylamino groups regulate the energy levels of PPh 4 + , reducing charge injection barriers. Notably, electroluminescent devices are achieved with a maximum external quantum efficiency (EQE max ) of 12.0% and large‐area emission of 4 × 4 cm 2 , underscoring their potential for next‐generation display technologies.
Article Details
Authors (16)
Bing Han
Yizhao Qing
State Key Laboratory of Chemical Resource Engineering Beijing Advanced Innovation Center for Soft Matter Science and Engineering College of Materials Science and Engineering Beijing University of Chemical Technology Beijing China
Runnan Yu
Zhuoxu Liu
State Key Laboratory of Chemical Resource Engineering Beijing Advanced Innovation Center for Soft Matter Science and Engineering College of Materials Science and Engineering Beijing University of Chemical Technology Beijing China
Qian Dang
Hui Li
Qianglong Lv
Chen Zhang
Shenzhen Institute for Quantum Science and Engineering, Department of Chemistry, and Department of Physics
Yuyi Han
Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education College of Chemistry Beijing Normal University Beijing 100875 China
Yang Zhang
Peijin Ma
State Key Laboratory of Chemical Resource Engineering Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical Technology Beijing 100029 China
Changxiao Li
State Key Laboratory of Chemical Resource Engineering Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical Technology Beijing 100029 China
Shihao Sha
State Key Laboratory of Chemical Resource Engineering Beijing Advanced Innovation Center for Soft Matter Science and Engineering College of Materials Science and Engineering Beijing University of Chemical Technology Beijing China
Qirui Hou
Key Laboratory of Brain-Like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University , Baoding 071002,
Biao Zhao
Zhan'ao Tan
Beijing University of Chemical Technology Beijing China