Please use this identifier to cite or link to this item:
http://dr.iiserpune.ac.in:8080/xmlui/handle/123456789/8125| Title: | Emissive Dark Excitons in Monoclinic Two-Dimensional Hybrid Lead Iodide Perovskites |
| Authors: | SHINDE, APARNA RAJPUT, PARIKSHIT KUMAR MAKHIJA, URMILA TANWAR, RITEEKA MANDAL, PANKAJ NAG, ANGSHUMAN Dept. of Chemistry |
| Keywords: | Hybrid lead halide perovskite Dark exciton Exciton fine structure 2D layered perovskite Low-temperature photoluminescence 2023-AUG-WEEK1 TOC-AUG-2023 2023 |
| Issue Date: | Aug-2023 |
| Publisher: | American Chemical Society |
| Citation: | Nano Letters, 23(15), 6985–6993. |
| Abstract: | Typically, bright excitons (XB) emit light in two-dimensional (2D) layered hybrid perovskites. There are also dark excitons (XD), for which radiative recombination is spin-forbidden. Application of a magnetic field can somewhat relax the spin-rule, yielding XD emission. Can we obtain XD light emission in the absence of a magnetic field? Indeed, we observe unusually intense XD emission at ∼7 K for (Rac-MBA)2PbI4, (Rac-4-Br-MBA)2PbI4, and (R-4-Br-MBA)2PbI4 (Rac-MBA: racemic methylbenzylammonium), which crystallize in a lower symmetry monoclinic phase. For comparison, orthorhombic (R-MBA)2PbI4 does not exhibit XD emission. XD has a lower energy than XB, with energy difference ΔE. In monoclinic samples, ΔE ∼ 20 meV is large enough to suppress the thermal excitation of XD to XB, at temperatures <30 K. Consequently, XD recombines by emitting light with a long lifetime (∼205 ns). At higher temperatures, the emission switches to the spin-allowed XB (lifetime < 1 ns) |
| URI: | https://doi.org/10.1021/acs.nanolett.3c01627 http://dr.iiserpune.ac.in:8080/xmlui/handle/123456789/8125 |
| ISSN: | 1530-6984 1530-6992 |
| Appears in Collections: | JOURNAL ARTICLES |
Files in This Item:
There are no files associated with this item.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.