The emission quenching of upconversion nanoparticles coated with amorphous silica by fluorescence resonance energy transfer: A mercury-sensing nanosensor excited by near-infrared radiation

Liqiang Wang; Tenghui Wang; Mingji Shao; Wenbo Jing; Jiayi Yu; Maoxian Wang; Jianxin Liu; Liang Liu

doi:10.1016/j.saa.2021.119608

The emission quenching of upconversion nanoparticles coated with amorphous silica by fluorescence resonance energy transfer: A mercury-sensing nanosensor excited by near-infrared radiation

Spectrochim Acta A Mol Biomol Spectrosc. 2021 Jun 5:254:119608. doi: 10.1016/j.saa.2021.119608. Epub 2021 Feb 22.

Authors

Liqiang Wang¹, Tenghui Wang², Mingji Shao³, Wenbo Jing³, Jiayi Yu³, Maoxian Wang³, Jianxin Liu⁴, Liang Liu⁵

Affiliations

¹ Department of Petroleum Engineering, Shengli College, China Petroleum University, Shandong Dongying 257061, China. Electronic address: 2017033@slcupc.edu.cn.
² Department of Petroleum Engineering, Shengli College, China Petroleum University, Shandong Dongying 257061, China.
³ Exploration and Development Research Institute of TuHa Oilfield Company, CNPC, XinJiang Hami 839009, China.
⁴ College of Petroleum Engineering, Yangtze University, Wuhan 430100, China.
⁵ School of Materials Science & Engineering, Jiangsu University, Zhenjiang 212013, China.

PMID: 33676344
DOI: 10.1016/j.saa.2021.119608

Abstract

In this paper, a rhodamine derivative was synthesized as a probe for Hg(II) detection. Its spectral response and sensing mechanism towards Hg(II) were discussed carefully. It was found that its absorption and emission were increased by Hg(II), via a direct bonding stoichiometry of 1:1. Its association constant was determined with absorption titration as 2.59 × 10⁵ M^-1, which suggested a coordination procedure between Hg(II) and this rhodamine probe. It showed good selectivity towards Hg(II) over competing metal cations, no increased emission or absorption was observed in the presence of interfering metal cations. It was then covalently grafted onto silica (SiO₂)-encapsulated upconversion nanoparticles (UCNPs). Upon near-infrared (NIR) excitation (980 nm), RHO accepted energy from these UCNPs through a FRET (fluorescence resonance energy transfer) procedure, quenching their upconversion emission. A sensing response towards Hg(II) was thus constructed. Good linearity and selectivity were still preserved in this composite sample. On the other hand, this work found a different phenomenon from literature cases, which was the emission absence of rhodamine emission in this composite structure. Detailed analysis suggested that rhodamine emission absence was caused by its self-quenching effect.

Keywords: Hg(2+) ion; Near-infrared light; Silica coating; Upconversion nanoparticles.