Green and facile synthesis of silicon-doped carbon dots and their use in detection of Hg2+ and visualization of latent fingerprints

Abstract

Mercury (Hg) is the most toxic heavy metal and can lead to severe irreversible injury to human health and serious pollution. It is of great significance to explore precise and facile detection methods for preventing environmental pollution and ecological problems. Herein, silicon-doped carbon dots (Si-CDs) with bright blue emission were fabricated and employed as a fluorescent probe for the quantitative detection of Hg²⁺. Possessing high photostability and excellent solubility in water, the Si-CDs exhibit an efficient response to Hg²⁺ by a “on–off” switching strategy. As a sensing probe, Si-CDs exhibit a good linear relationship with Hg²⁺ in the concentration range of 0.008–0.4 μM with a limit of detection of 33 nM. Moreover, the proposed method was successfully applied to monitor Hg²⁺ in different real water samples with satisfactory recoveries of 96.2%–99.5%, demonstrating their excellent accuracy and environment tolerance. Notably, the Si-CD powder obtained by lyophilization can visualize latent fingerprints with second-level details. The results serve to underscore how CDs designed for multiple applications in detection can be exploited to provide promising multi-functional fluorescent materials.