(Invited) Exploring and Manipulating Luminescence Centers in Lead Halide Perovskites through Hydrostatic Pressure

The application of hydrostatic pressure to materials induces changes in lattice constants, vibrational spectra, and electron-phonon interactions, thereby altering the optoelectronic properties of semiconductors. Consequently, hydrostatic pressure has become a widely utilized tool for investigating and enhancing the optical properties of organic/inorganic halide perovskites and their nanostructures. In this presentation, I will discuss the impact of hydrostatic pressure on two distinct types of luminescence centers in perovskite materials. The first type of luminescence centers originates from excitons within perovskite nanocrystals. I will discuss how hydrostatic pressure serves as a valuable tool for elucidating the origin of luminescence in low-dimensional perovskites, including 2D CsPb 2 Br 5 , 0D Cs 4 PbBr 6 , and 2D Ruddlesden-Popper Hybrid Perovskite Crystals. The second type of luminescence centers exhibit broadband optical emission from self-trapped excitons in low-dimensional perovskites. I will present our findings on the observation of strong exciton-phonon coupling and demonstrate how hydrostatic pressure can be employed to modulate electron-phonon coupling, offering a means to finely tune the broad emission spectrum. References: [1] J. Bao, V. G. Hadjiev, “Origin of Luminescent Centers and Edge States in Low-Dimensional Lead Halide Perovskites: Controversies, Challenges and Instructive Approaches”. Nano-Micro Lett . 11 , 26 (2019). [2] Chong Wang, Yanan Wang, Xinghua Su, Viktor G. Hadjiev, Shenyu Dai, Zhaojun Qin, Hector A Calderon Benavides, Yizhou Ni, Qiang Li, Jie Jian, Md Kamrul Alam, Haiyan Wang, Francisco C. Robles-Hernandez, Yan Yao, Shuo Chen, Qingkai Yu, Guoying Feng, Zhiming Wang, Jiming Bao, “Extrinsic Green Photoluminescence from the Edges of Two-dimensional Cesium Lead Halides”, Advanced Materials 31 , 1902492 (2019). [3] Zhaojun Qin, Shenyu Dai, Viktor G. Hadjiev, Chong Wang, Lixin Xie, Yizhou Ni, Chunzheng Wu, Guang Yang, Shuo Chen, Liangzi Deng, Qingkai Yu, Guoying Feng, Zhiming M. Wang, Jiming Bao, “Revealing the Origin of Luminescence Center in 0D Cs 4 PbBr 6 Perovskite”, Chem. Mater. 31 , 9098-9104 (2019). [4] Zhaojun Qin, Shenyu Dai, Chalapathi Charan Gajjela, Chong Wang, Viktor G Hadjiev, Guang Yang, Jiabing Li, Xin Zhong, Zhongjia Tang, Yan Yao, Arnold M Guloy, Rohith Reddy, David Mayerich, Liangzi Deng, Qingkai Yu, Guoying Feng, Hector A Calderon, Francisco C Robles Hernandez, Zhiming M Wang, Jiming Bao, “Spontaneous Formation of 2D/3D Heterostructures on the Edges of 2D Ruddlesden-Popper Hybrid Perovskite Crystals”, Chem. Mater . 32 , 5009 (2020). [5] Shenyu Dai, Xinxin Xing, Viktor G. Hadjiev, Zhaojun Qin, Tian Tong, Guang Yang, Chong Wang, Lijuan Hou, Liangzi Deng, Zhiming Wang, Guoying Feng, Jiming Bao, “Theory and experiments of pressure-tunable broadband light emission from self-trapped excitons in metal halide crystals”, Materials Today Physics 30 , 100926 (2023).