Pressure-Suppressed Carrier Trapping Leads to Enhanced Emission in Two-Dimensional Perovskite (HA)2(GA)Pb2I7 |
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| Authors: | Songhao Guo Yongsheng Zhao Kejun Bu Yongping Fu Hui Luo Mengting Chen Matthew P Hautzinger Yingqi Wang Prof Song Jin Prof Wenge Yang Prof Xujie Lü |
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| Institution: | 1. Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai, 201203 P. R. China;2. Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706 USA |
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| Abstract: | A remarkable PL enhancement by 12 fold is achieved using pressure to modulate the structure of a recently developed 2D perovskite (HA)2(GA)Pb2I7 (HA=n-hexylammonium, GA=guanidinium). This structure features a previously unattainable, extremely large cage. In situ structural, spectroscopic, and theoretical analyses reveal that lattice compression under a mild pressure within 1.6 GPa considerably suppresses the carrier trapping, leading to significantly enhanced emission. Further pressurization induces a non-luminescent amorphous yellow phase, which is retained and exhibits a continuously increasing band gap during decompression. When the pressure is released to 1.5 GPa, emission can be triggered by above-band gap laser irradiation, accompanied by a color change from yellow to orange. The obtained orange phase could be retained at ambient conditions and exhibits two-fold higher PL emission compared with the pristine (HA)2(GA)Pb2I7. |
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| Keywords: | carrier trapping high-pressure chemistry phase transitions photoluminescence enhancement 2D halide perovskites |
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