Available on-demand - S.EN01.10.07
Origin of Luminescent Centers and Edge States in Low Dimensional Lead Halide Perovskites
Feng Lin2,Jiming Bao1,Zhiming Wang2,Liangzi Deng1,Zhaojun Qin2,Shen-yu Dai3,Shuo Chen1,Lixin Xie1,Chong Wang4,Chunzheng Wu2,Guang Yang1,Guoying Feng3,Viktor Hadjiev1,Qingkai Yu5,Yizhou Ni1,Qiang Li6,Haiyan Wang6,Kamrul Alam1,Francisco Robles Hernandez1,Jie Jian6,Hector Calderon Benavides7,Yan Yao1,Yanan Wang1,Xinghua Su8
University of Houston1,University of Electronic Science and Technology of China2,Sichuan University3,Yunnan University4,Texas State University5,Purdue University6,Instituto Politecnico Nacional, ESFM-IPN, UPALM7,Chang’an University8
With only a few deep-level defect states having a high formation energy and dominance of shallow carrier non-trapping defects, the defect-tolerant electronic and optical properties of lead halide perovskites have made them appealing materials for high-efficiency, low-cost, solar cells and light-emitting devices. As such, recent observations of apparently deep-level and highly luminescent states in low-dimensional perovskites have attracted enormous attention as well as intensive debates. The observed green emission in 2D CsPb2Br5 and 0D Cs4PbBr6 poses an enigma over whether it is originated from intrinsic point defects or simply from highly luminescent CsPbBr3 nanocrystals embedded in the otherwise transparent wide bandgap semiconductors. The nature of deep-level edge emission in 2D Ruddlesden-Popper perovskites is also not well understood. In this talk, I will analyze the experimental evidences that support the opposing interpretations and discuss challenges and root causes for the controversy. I will then present experimental approaches that can better correlate property with structure of a material and help resolve the controversies. Using combined Raman-photoluminescence under hydrostatic pressure in a diamond anvil cell, we prove that CsPbBr3 nanocrystals are responsible for the bright green emissions in both 2D CsPb2Br5 and 0D Cs4PbBr6. Finally, I will show our preliminary understanding of the edge emission in 2D R-P perovskites.
1. 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 1902492 (2019). DOI: 10.1002/adma.201902492.
2. Jiming Bao, Viktor 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).
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 Cs4PbBr6 Perovskite”, Chem. Mater. 2019, https://doi.org/10.1021/acs.chemmater.9b03426