Synthesis of rhenium disulfide nanodots exhibiting pH-dependent fluorescence and phosphorescence for anticounterfeiting and hazardous gas detection

Manivannan Madhu; S Santhoshkumar; Wei-Bin Tseng; A Santhana Krishna Kumar; Wei-Lung Tseng

doi:10.1016/j.saa.2024.124240

Synthesis of rhenium disulfide nanodots exhibiting pH-dependent fluorescence and phosphorescence for anticounterfeiting and hazardous gas detection

Spectrochim Acta A Mol Biomol Spectrosc. 2024 Jul 5:315:124240. doi: 10.1016/j.saa.2024.124240. Epub 2024 Apr 5.

Authors

Manivannan Madhu¹, S Santhoshkumar¹, Wei-Bin Tseng², A Santhana Krishna Kumar³, Wei-Lung Tseng⁴

Affiliations

¹ Department of Chemistry, National Sun Yat-sen University, No. 70 Lienhai Rd., Kaohsiung 80424, Taiwan.
² Department of Environmental Engineering, Da-Yeh University. No.168, University Rd., Dacun, Changhua 515006, Taiwan. Electronic address: tsengwb@mail.dyu.edu.tw.
³ Department of Chemistry, National Sun Yat-sen University, No. 70 Lienhai Rd., Kaohsiung 80424, Taiwan; Faculty of Geology, Geophysics and Environmental Protection, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow city, Poland.
⁴ Department of Chemistry, National Sun Yat-sen University, No. 70 Lienhai Rd., Kaohsiung 80424, Taiwan; School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, No.100, Shiquan 1st Rd., 80708, Kaohsiung, Taiwan. Electronic address: tsengwl@mail.nsysu.edu.tw.

PMID: 38608558
DOI: 10.1016/j.saa.2024.124240

Abstract

The synthesis and characterization of ReS₂ nanodots (NDs) are detailed, by highlighting their structure, morphological, and optical properties. ReS₂ NDs were synthesized using NH₄ReO₄ as a rhenium source, thiourea as a sulfur source, and N-acetyl cysteine as a capping agent. The synthesis involved the hydrothermal reaction of these precursors, leading to the nucleation and growth of ReS₂ NDs. Characterization techniques including transmission electron microscopy, energy dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy confirmed the formation of ReS₂ NDs with a spherical morphology, crystalline structure, and rich sulfur sites. The fluorescence behavior of ReS₂ NDs was found to be influenced by the solution pH, with fluorescence intensity increasing with rising pH values. This pH-dependent fluorescence response was attributed to the dissociation of functional groups and the subsequent impact on the excited-state proton transfer process. The fluorescence intensity of ReS₂ NDs showed a correlation with solution pH, enabling pH detection from 3.0 to 12.5 with an interval of 0.5 pH unit. Additionally, the incorporation of ReS₂ NDs into a polyvinyl alcohol (PVA) matrix resulted in pH-sensitive phosphorescence, offering a new avenue for pH sensing. The strong interaction between PVA and ReS₂ NDs was proposed to enhance phosphorescence intensity and trigger a blue shift in the phosphorescent peak at high pH. The ReS₂ NDs/PVA-deposited filter paper exhibited pH-sensitive fluorescence and phosphorescence, which could be utilized as unique identifiers or authentication markers. Moreover, the ReS₂ NDs/PVA-deposited filter paper showed potential for discriminating between hydrogen chloride and ammonia, based on their distinct fluorescence and phosphorescence responses.

Keywords: Fluorescence sensing; HCl and Ammonia adsorption; Phosphorescence sensing; ReS(2) NDs; pH depended Anticounterfeit encryption.