| Autor: |
Ratté J; Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7, Canada., Macintosh MF; Department of Chemistry, University of Western Ontario, London, ON N6A 5B7, Canada., DiLoreto L; Department of Chemistry, University of Western Ontario, London, ON N6A 5B7, Canada., Liu J; Department of Chemistry, University of Western Ontario, London, ON N6A 5B7, Canada., Mihalyi-Koch W; Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States., Hautzinger MP; Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States., Guzei IA; Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States., Dong Z; Shanghai Synchrotron Radiation Facility (SSRF), Shanghai Institute of Applied Physics, CAS, Shanghai, 201204, PR China., Jin S; Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States., Song Y; Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7, Canada.; Department of Chemistry, University of Western Ontario, London, ON N6A 5B7, Canada. |
| Abstrakt: |
Compared with their 3D counterparts, 2D hybrid organic-inorganic halide perovskites (HOIPs) exhibit enhanced chemical stabilities and superior optoelectronic properties, which can be further tuned by the application of external pressure. Here, we report the first high-pressure study on CMA 2 PbI 4 (CMA = cylcohexanemethylammonium), a 2D HOIP with a soft organic spacer cation containing a flexible cyclohexyl ring, using UV-visible absorption, photoluminescence (PL) and vibrational spectroscopy, and synchrotron X-ray microdiffraction, all aided with density functional theory (DFT) calculations. Substantial anisotropic compression behavior is observed, as characterized by unprecedented negative linear compressibility along the b axis. Moreover, the pressure dependence of optoelectronic properties is found to be in strong contrast with those of 2D HOIPs with rigid spacer cations. DFT calculations help to understand the compression mechanisms that lead to pressure-induced bandgap narrowing. These findings highlight the important role of soft spacer cations in the pressure-tuned optoelectronic properties and provide guidance to the design of new 2D HOIPs. |
