Spectroscopic indications of room-temperature electron-hole droplets in optically excited CH3NH3PbBr3 single crystals

• Main Authors: Cao, L. (Author), Chen, C.-X (Author), Chen, X.-C (Author), Gao, M. (Author), Ma, G.-Z (Author), Rao, J.-R (Author), Shi, D. (Author), Wang, J. (Author)
• Format: Article
• Language: English
• Published: Cell Press 2022
• Subjects: absorption; electron-hole droplets; exciton; optical hysteresis; photoluminescence; plasma
• Online Access: View Fulltext in Publisher
• ISBN: 26663864 (ISSN)
• DOI: 10.1016/j.xcrp.2022.100896

An electron-hole droplet is a unique form of matter that occurs as a metallic phase in semiconductors, and its formation has been almost exclusively linked to cryogenic condensation of long-lived excitons. Creating room-temperature electron-hole droplets in semiconductors has remained an outstanding challenge. Here, we report plausible spectroscopic indications of a cloud of room-temperature electron-hole droplets in optically excited CH3NH3PbBr3 single crystals. Droplet characters shown by the excitation threshold and optical hysteresis are demonstrated. The observed two-stage photoluminescence decaying histogram indicates rapid thermal dissociation of room-temperature excitons into hot electron-hole plasma vapor and subsequent droplet nucleation toward a metastable size. Our study sheds light on the vapor-to-liquid phase evolution in optically excited crystal bulk of direct band gap semiconductors and paves the way for further exploration toward intriguing optoelectronic and valleytronic applications. © 2022 The Author(s)