Results
Title

Boosting self-trapped exciton emission from Cs<sub>3</sub>Cu<sub>2</sub>I<sub>5</sub> nanocrystals by doping-enhanced exciton-phonon coupling.

Authors

Li, Xiaohan; Liu, Aijun; Wang, Zhaoyu; Wei, Youchao; Lin, Qun; Chen, Yameng; Liu, Yongsheng; Hong, Maochun

Abstract

Self-trapped excitons (STEs) emission from halide perovskites with strong exciton-phonon coupling has attracted considerable attention due to the widespread application in optoelectronic devices. Nevertheless, the in-depth understanding of the relationship between exciton-phonon coupling and luminescence intensity remains incomplete. Herein, a doping-enhanced exciton-phonon coupling effect is observed in Cs3Cu2I5 nanocrystals (NCs), which leads to a remarkable increasement of their STEs emission efficiency. Mechanism study shows that the hetero-valent substitution of Cu with alkaline-earth metal ions (AE2 ) causes a greater degree of Jahn–Teller distortion between the ground state and excited state structures of [Cu2I5]3− clusters as evidenced by our spectral analysis and first-principles calculations. As a consequence, an X-ray detector based on these Cs3Cu2I5:AE NCs delivers an X-ray imaging resolution of up to 10 lp·mm−1 and a low detection limit of 0.37 µGyair·s−1, disclosing the potential of doping-enhanced exciton-phonon coupling effect in improving STEs-emission and practical application for X-ray imaging.

Subjects

NANOCRYSTALS; X-ray imaging; OPTOELECTRONIC devices; EXCITED states; PEROVSKITE; CESIUM isotopes

Publication

Nano Research, 2023, Vol 16, Issue 7, p10476

ISSN

1998-0124

Publication type

Academic Journal

DOI

10.1007/s12274-023-5708-9