Author(s): Xu, KX (Xu, Kai-Xuan); Zhou, ZR (Zhou, Ziren); Zhang, J (Zhang, Jun)

Source: JOURNAL OF PHYSICAL CHEMISTRY LETTERS Volume: 14 Issue: 1 Pages: 32-37 DOI: 10.1021/acs.jpclett.2c03514 Published: JAN 12 2023

Abstract: Phonon-assisted upconversion photoluminescence (UCPL) plays an important role in a wide range of fields such as optical refrigeration, sensitive optical thermometry, quantum state control, and upconversion optoelectronics. High photoluminescence quantum yield (PLQY) and strong electron-phonon coupling are two basic prerequisites of efficient UCPL materials. The self-trapped exciton (STE) system with the above-mentioned advantages hints that it may be a good candidate for phonon-assisted UCPL. Here, we synthesized Rb2CuCl3 single crystals (SCs) which yield a high PLQY of the STE emission at 400 nm, and an efficient phonon-assisted UCPL was demonstrated at room temperature. By exponentially fitting the intensity of temperature -dependent UCPL spectra, we obtained an optical thermometry sensitivity of SCs up to 6 mK at 295 K. We also propose that net cooling would be possible if the PLQY is improved up to 91.5% with 345 nm excitation. Our results open a new door to explore laser cooling in STE systems.

Accession Number: WOS:000918921700001

PubMed ID: 36563108

Author Identifiers:

Author        Web of Science ResearcherID        ORCID Number

Zhang, Jun                  0000-0002-9831-6796

ISSN: 1948-7185

Full Text: https://pubs.acs.org/doi/10.1021/acs.jpclett.2c03514