New progress in circularly polarized perovskite luminescence research at East China University of Science and Technology

Recently, the team of Professor Zhu Weihong, Professor Wu Yongzhen and Professor Zheng Zhigang from the School of Chemistry and Molecular Engineering of East China University of Science and Technology has made progress in the research of circularly polarized perovskite luminescence .
Circularly polarized luminescence of helical bilayer devices" was published in the well-known journal "Material" .

It is reported that circularly polarized luminescence (CPL) refers to the phenomenon that the light-emitting system emits different left-handed and right-handed circularly polarized light.
prospects
.
Metal halide perovskite materials have excellent properties such as high fluorescence quantum efficiency, narrow emission peaks, and tunable emission wavelengths, and are expected to be ideal new CPL materials
.
At present, the reported perovskite CPL materials (such as chiral two-dimensional perovskites, chiral ligand-modified perovskite nanocrystals, etc.
) have problems such as small asymmetry factor (g lum value) and low luminous efficiency, and Its stability is rarely studied, which severely limits its practical application
.
Incorporating perovskite nanocrystals into chiral nematic liquid crystals can significantly improve the g lum value of CPL, but the hybrid system not only seriously destroys the structural stability of perovskite, but also affects the orderly arrangement of liquid crystal molecules, weakening its effect on the CPL.
Circular polarization modulation capability of light
.
Therefore, how to obtain CPLs with high luminous efficiency and high glum value still faces great challenges
.

In order to solve the above problems, the research team stabilized perovskite by polymer and constructed a perovskite-liquid crystal device (PeLC) with a double-layer structure, which solved the key problem of poor compatibility between perovskite and liquid crystal, and improved the performance of perovskite.
Structural stability, improving the ordered arrangement of liquid crystal molecules, and realizing a perovskite CPL with high luminous efficiency and high stability, its g lum is as high as 1.
9, which is close to the theoretical limit of 2.
0, and a circularly polarized light pattern is displayed based on the device structure.
This work opens up new ideas for the realization of high-quality circularly polarized perovskite luminescence and its device application
.

The above research work was mainly completed by Liu Shuaijun, a doctoral student from the School of Chemistry and Molecular Engineering, and Liu Xuan, a doctoral student from the School of Physics, under the joint guidance of Professor Zhu Weihong, Professor Wu Yongzhen and Professor Zheng Zhigang, and received the careful guidance of Academician Tian He
.
In addition, the research work has also been supported by the National Natural Science Foundation of China, the Shanghai Municipal Education Commission’s Scientific Research and Innovation Program, the Shanghai Municipal Science and Technology Major Project, the Program for Introducing Discipline Talents to Universities, the Shanghai Education Development Foundation, the “Dawning Program” of the Shanghai Municipal Education Commission, and the Shanghai Science and Technology Funding support from the committee and the Feringa Nobel Prize Scientist Joint Research Center
.