Superenhancement Photon Upconversion Nanoparticles for Photoactivated Nanocryometer
Qiqing Li, Xiaoyu Xie, Han Wu, Hao Chen, Wang Wang, Xianggui Kong, Yulei Chang
Abstract
Highly doped lanthanide luminescent nanoparticles exhibit unique optical properties, providing exciting opportunities for many ground-breaking applications, such as super-resolution microscopy, deep-tissue bioimaging, confidentiality, and anticounterfeiting. However, the concentration-quenching effect compromises their luminescence efficiency/brightness, hindering their wide range of applications. Herein, we developed a low-temperature suppression cross-relaxation strategy, which drastically enhanced upconversion luminescence (up to 2150-fold of green emission) in Er 3+ -rich nanosystems. The cryogenic field opens the energy transport channel of Er 3+ multiphoton upconversion by further suppressing phonon-assisted cross-relaxation. Our results provide direct evidence for understanding the energy loss mechanism of photon upconversion, deepening a fundamental understanding of the upconversion process in highly doped nanosystems. Furthermore, it also suggests the potential applications of upconversion nanoparticles for extreme ambient-temperature detection and anticounterfeiting.