A temperature sensor based on the enhanced upconversion luminescence of Li+ doped NaLuF4:Yb3+, Tm3+/Er3+ nano/microcrystals. Issue 26 (9th May 2018)

• Record Type: Journal Article
• Authors: Qiang, Qinping; Du, Shanshan; Ma, Xinlong; Chen, Wenbo; Zhang, Gangyi; Wang, Yuhua
• Is Part Of: Dalton transactions. Volume 47:Issue 26(2018)
• Page Start: 8656
• Page End: 8662
• Publication Date: 2018-05-09
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c8dt00928g
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : In this paper, fluorescent and optical temperature sensing bi-functional Li + -doping NaLuF4 :Ln (Ln = Yb 3+, Tm 3+ /Er 3+ ) nanocrystals were synthesized via a simple hydrothermal method using oleic acid as a capping ligand. Abstract : In this paper, fluorescent and optical temperature sensing bi-functional Li + -doping NaLuF4 :Ln (Ln = Yb 3+, Tm 3+ /Er 3+ ) nanocrystals were synthesized via a simple hydrothermal method using oleic acid as a capping ligand. The crystal phase, size, upconversion (UC) properties, and optical temperature sensing characteristics of the crystals can be easily modified by Li + doping. The results reveal that additional Li + can promote the transformation from the hexagonal phase to the cubic phase and reduce the size of the nanocrystals. In addition, NaLuF4 :Ln (Ln = Yb 3+, Tm 3+, Li + ) nanocrystals present efficient near infrared (NIR) emission, which is beneficial for in vivo biomedical applications due to the increased penetration depth and low radiation damage of NIR light in bio-tissues. More importantly, under 980 nm excitation, the temperature dependent UCL from the 2 H11/2 and 4 S3/2 levels of Er 3+ ions in NaLuF4 :Yb 3+, Er 3+, Li + microcrystals was investigated systematically. The fluorescence intensity ratios (FIR) of the pairs of thermally coupled levels were studied as a function of temperature in the range of 298–523 K. The maximum sensor sensitivities were found to be about 0.0039 K −1 (523 K) by exploiting the UC emissions from the 2 H11/2 and 4 S3/2 levels. This suggests that the Li + -doped upconversion luminescence (UCL) materials are promising prototypes for application as multi-mode probes for use in bio-separation and optical thermometers.