Pressure-controlled free exciton and self-trapped exciton emission in quasi-one-dimensional hybrid lead bromides.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39191775.
- Also identified by DOI 10.1038/s41467-024-51836-2 and PMC identifier 11349761.
- Licence recorded as CC BY-NC-ND.
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Abstract
Hybrid metal halides represent a novel type of semiconductor light emitters with intriguing excitonic emission properties, including free exciton emission and self-trapped exciton emission. Achieving precise control over these two excitonic emissions in hybrid metal halides is highly desired yet remains challenging. Here, the complete transformation from intrinsically broadband self-trapped exciton emission to distinctively sharp free exciton emission in a quasi-one-dimensional hybrid metal halide (C<sub>2</sub>H<sub>10</sub>N<sub>2</sub>)<sub>8</sub>[Pb<sub>4</sub>Br<sub>18</sub>]·6Br with a ribbon width of n = 4, is successfully achieved based on high-pressure method. During compression, pressure-induced phonon hardening continuously reduces exciton-phonon coupling, therefore suppressing excitonic localization and quenching the original self-trapped exciton emission. Notably, further compression triggers excitonic delocalization to induce intense free exciton emission, accompanied with reduced carrier effective masses and improved charge distribution. Controlled high-pressure investigations indicate that the ribbon width of n > 2 is necessary to realize excitonic delocalization and generate free exciton emissions in similar quasi-one-dimensional hybrid metal halides. This work presents an important photophysical process of excitonic transitions from self-trapped exciton emission to free exciton emission in quasi-one-dimensional hybrid metal halides without chemical regulation, promoting the rational synthesis of hybrid metal halides with desired excitonic emissions.