Unraveling the Electronic Structures of Neodymium in LiLuF4 Nanocrystals for Ratiometric Temperature Sensing

• DOI: 10.1002/advs.201802282
• Publication Date: 2019-03-14T07:27:44Z
• Authors: Ping Huang; Wei Zheng; Datao Tu; Xiaoying Shang; Meiran Zhang; Renfu Li; Jin Xu; Yan Liu; Xueyuan Chen
• Keywords: LiLuF4 nanocrystals; site symmetry; Science; Q; Full Papers; energy level; 01 natural sciences; neodymium; temperature sensing; 0104 chemical sciences

AbstractNd3+‐doped near‐infrared (NIR) luminescent nanocrystals (NCs) have shown great promise in various bioapplications. A fundamental understanding of the electronic structures of Nd3+ in NCs is of vital importance for discovering novel Nd3+‐activated luminescent nanoprobes and exploring their new applications. Herein, the electronic structures of Nd3+ in LiLuF4 NCs are unraveled by means of low‐temperature and high‐resolution optical spectroscopy. The photoactive site symmetry of Nd3+ in LiLuF4 NCs and its crystal‐field (CF) transition lines in the NIR region of interest are identified. By taking advantage of the well‐resolved and sharp CF transition lines of Nd3+, the application of LiLuF4:Nd3+ NCs as sensitive NIR‐to‐NIR luminescent nanoprobes for ratiometric detection of cryogenic temperature with a linear range of 77–275 K is demonstrated. These findings reveal the great potential of LiLuF4:Nd3+ NCs in temperature sensing and also lay a foundation for future design of efficient Nd3+‐based luminescent nanoprobes.