The research team of Qu Bo, Chen Zhijian and Xiao Lixin from the School of Physics has made a series of progress in the field of lead-free double perovskites

The lead-free double perovskite Cs ₂ AgBiBr ₆ is considered to be a promising new optoelectronic functional material due to its excellent properties such as non-toxicity, intrinsic thermal stability, and high optical absorption coefficient; however, this material also has optical properties.

Recently, a joint research team of Associate Professor Qu Bo, Professor Chen Zhijian and Professor Xiao Lixin from the Institute of Modern Optics, School of Physics, Peking University, State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, has synthesized iron-doped double perovskites by cooling and crystallization.

The joint research team proved through elemental analysis and X-ray diffraction experiments that only about 1% of Fe ions were doped into the Cs ₂ AgBiBr ₆ lattice, which caused lattice shrinkage; using the third harmonic generation effect and fluorescence spectroscopy Measurement, it is found that the forbidden band width of Cs ₂ AgBiBr ₆ does not change after Fe doping, but a new intermediate energy level appears in the intrinsic forbidden band, so that the material has the ability to absorb near-infrared light (Fig.

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The related research results are titled " Expanding the light absorption of Cs ₂ AgBiBr ₆ to the near-infrared region (≈1350 nm) through intermediate energy levels ", published online on December 10, 2021 in Advanced Functional Materials ; Class of 2020 Doctoral student Liu Ganghong and 2017 doctoral student Zhang Zehao are the co-first authors, Qu Bo and Xiao Lixin are the co-corresponding authors, and other collaborators include Chen Zhijian, Shi Junjie, Liu Kaihui, etc.

In addition, lead-free double perovskite quantum dots have the characteristics of broad-spectrum emission and are suitable for the preparation of white light-emitting diode devices

Qubo's research group has conducted in-depth and systematic research on this important scientific issue: firstly, a cubic phase double perovskite with regular crystal structure and uniform morphology (Cs ₂ AgIn _0.

The related research results are titled " Lead _{-free Double Perovskite Cs 2} AgIn 0.

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The above series of research work is supported by the National Natural Science Foundation of China