A research team from Shenzhen University has successfully synthesized highly stable silver sulfide nanoclusters (Ag56) with near-infrared emission and long Stokes shifts, enabling highly sensitive ion sensing applications.
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The development of advanced fluorescent materials with near-infrared emission and long Stokes shifts is essential for modern biosensing and environmental monitoring. Silver sulfide nanoclusters, known for their unique optical properties and biocompatibility, have emerged as a strong candidate in this field.
The team from Shenzhen University, China, has made a notable breakthrough in synthesizing and applying silver sulfide nanoclusters for ion sensing.
The researchers successfully synthesized highly stable Ag56 nanoclusters using 4-vinylbenzoic acid (p-VBA) and tert-butyl mercaptan as ligands. By precisely controlling reaction parameters such as temperature and solvent, they not only achieved high-yield production but also captured key intermediates, including Ag20, Ag31, Ag32, Ag30-bpbenz, and Ag31-bpe.
These nanoclusters exhibit a fluorescence aggregation redshift phenomenon due to π–π interactions in the ligands, making them particularly well-suited for sensing applications.
The team also developed a fluorescence-enhanced sensor based on Ag56 nanoclusters, capable of detecting trace amounts of bromide (Br−) and iodide (I−) ions in water samples, with detection limits as low as 85 and 105 nM, respectively.
Operating in the near-infrared range, this sensor minimizes background interference and offers high tissue penetration, making it highly advantageous for bio-detection and in vivo diagnostics.
Their findings were published in the journal Polyoxometalates on February 25, 2025.
Our study provides new insights into the controlled synthesis of silver sulfide nanoclusters and their potential applications in ion sensing. The ability to capture reaction intermediates and manipulate their optical properties through ligand engineering opens up new possibilities for the development of highly sensitive and selective sensors.
Huayan Yang, Study Head and Professor, Shenzhen Key Laboratory of Nano-Biosensing Technology, Shenzhen University
The Ag56 nanoclusters, with their long Stokes shift and near-infrared emission, mark a significant step forward in fluorescent sensing. The research team anticipates that these findings will inspire further exploration into designing and applying silver sulfide nanoclusters across various sensing technologies.
Journal Reference:
Zhang, Z., et al. (2025) From intermediate capture to functional cluster construction: Synthesis of silver clusters and their Br−/I− sensing applications. Polyoxometalates. doi/10.26599/POM.2025.9140086