The synthesis of a series of fluorescent emitters and their application for dye lasing and cation sensing

Zixuan Yang; Yaqiang Tian; Sheng Cang; Leiyu Zhang; Liang Liu

doi:10.1016/j.saa.2020.118978

The synthesis of a series of fluorescent emitters and their application for dye lasing and cation sensing

Spectrochim Acta A Mol Biomol Spectrosc. 2021 Feb 5:246:118978. doi: 10.1016/j.saa.2020.118978. Epub 2020 Sep 24.

Authors

Zixuan Yang¹, Yaqiang Tian², Sheng Cang³, Leiyu Zhang², Liang Liu⁴

Affiliations

¹ Key Laboratory of Impact and Safety Engineering, Ministry of Education, Ningbo University, Ningbo 315211, China. Electronic address: yangzixuan@nbu.edu.cn.
² Key Laboratory of the Ministry of Education for Modern Metallurgy Technology, North China University of Science and Technology, Tangshan 063210, China.
³ Key Laboratory of Impact and Safety Engineering, Ministry of Education, Ningbo University, Ningbo 315211, China.
⁴ Green Intelligence Environmental School, Yangtze Normal University, Fuling, Chongqing 408100, China.

PMID: 33038857
DOI: 10.1016/j.saa.2020.118978

Abstract

The following paper reported four carbazole-modified fluorescent emitters. Their molecular structure and electronic transition were analyzed via their single crystal and theoretical calculation. Their photophysical parameters, including absorption, emission and quantum yield, were determined and discussed. It was found that the emission performance of benzo-thiazole-based dyes was better than that of benzo-imidazole-based dyes, owing to the electron-donating effect from the S atom. Upon the presence of metal cations, these photophysical parameters were re-measured. Benzo-thiazole-based dyes were found insensitive towards most metal cations, while benzo-imidazole-based dyes showed obvious photophysical variation upon these metal cations, including absorption red shift and emission quenching. Detailed sensing performance of a representative dye was discussed. A linear working curve with good selectivity was finally observed. Its sensing mechanism was confirmed as the coordination between metal cation and deprotonated benzo-imidazole group. Benzo-thiazole-based dyes showed amplified spontaneous emission (ASE) behavior, with threshold energy of ~220 μJ. Given the optimal condition, a highest ASE efficiency of ~2% was observed, with FWHM value of 6 nm and emission peak of 435 nm. The major novelty and advancement of these fluorescent dyes shall be the stable ASE output (dye 4) under UV excitation and the linear sensing curve with good selectivity (dye 3), which was a hard task for emission turn off sensing probes. We attributed its causation to the valent-recognizing sensing mechanism.

Keywords: ASE; Emission quenching; Laser dyes; Optical sensing.