@article{Zhang2020, 
author = {Ling Zhang and Xiaodan Li and Wang Wang and Xu Zhao and Xu Yan and Chenguang Wang and Haoqiang Bao and Yang Lu and Xianggui Kong and Fengmin Liu and Xiaomin Liu and Geyu Lu},
title = {Construction of self-sensitized LiErF4: 0.5% Tm3+@LiYF4 upconversion nanoprobe for trace water sensing},
year = {2020},
journal = {Nano Research},
volume = {13},
number = {10},
pages = {2803-2811},
keywords = {sensor, LiErF4, water detection, upconversion emission, self-sensitized},
url = {https://www.sciopen.com/article/10.1007/s12274-020-2932-4},
doi = {10.1007/s12274-020-2932-4},
abstract = {LiErF4 was commonly used as a dipolar-coupled antiferromagnet, and was rarely considered as a luminescent material. Herein, we achieved the strong red upconversion emission of LiErF4 simply by an inert shell coating, i.e., LiErF4@LiYF4. Owing to the unique and intrinsic ladder-like energy levels of Er3+ ions, this LiErF4 core-shell nanostructures present red emission (~ 650 nm) under multi-band excitation in the near-infrared (NIR) region (~ 808, ~ 980, and ~ 1,530 nm). A brighter and monochromic red emission can be further obtained via doping 0.5% Tm3+ into the LiErF4 core, i.e., LiErF4: 0.5% Tm3+@LiYF4. The enriched Er3+ ions and strong monochromic red emission natures make LiErF4: 0.5% Tm3+@LiYF4 nanocrystals very sensitive for trace water probing in organic solvents with detection limit of 30 ppm in acetonitrile, 50 ppm in dimethyl sulfoxide (DMSO), and 58 ppm in N, N-dimethyl- formamide (DMF) under excitation of 808 nm. Due to their superior chemical and physical stability, these nanoprobes exhibit excellent antijamming ability and recyclability, offering them suitable for real-time and long-term water monitoring.}
}