Since a vast majority of mercury ion (Hg²⁺)-responsive fluorescence probes suffer from significant false positive interference in practical applications originating from their fluorescence quenching mechanism, it is still a challenge to develop a fluorescence enhancement sensor for its assay. In this work, single hexagonal boron nitride quantum dots (BNQDs)-based probe was presented for Hg²⁺ assay in a fluorescence enhancement-based ratiometric manner. When Hg²⁺ was present, the BNQDs exhibited a new fluorescence emission peak located at 560 nm under 280 nm excitation, while the original blue fluorescence of the probe at 461 nm was quenched, realizing a ratiometric fluorescence response to Hg²⁺. Furthermore, it is found that fluorescence enhancement at 560 nm was dramatically suppressed under 365 nm excitation, the mechanism behind this phenomenon has been explored by experiments and relevant theories. In addition to high selectivity and detection sensitivity with LOD of 0.7 nM, the prepared probe successfully demonstrated its accuracy in Hg²⁺ detection in environmental water samples. Moreover, the probe could be adopted for paper sensor design, and an accurate and reliable cell phone-based portable platform was demonstrated for Hg²⁺ assay with LOD of 1.9 nM, suggesting its potential in point-of-care detection application.

由于绝大多数汞离子（Hg ²⁺）响应荧光探针在实际应用中由于其荧光猝灭机制而受到显着的假阳性干扰，因此开发用于其测定的荧光增强传感器仍然是一个挑战。在这项工作中，基于单个六方氮化硼量子点 (BNQD) 的探针以基于荧光增强的比率计方式用于 Hg ²⁺测定。当Hg ²⁺存在时，BNQDs在280 nm激发下在560 nm处出现新的荧光发射峰，而探针原有的461 nm蓝色荧光被猝灭，实现了对Hg ^{2+的比例荧光响应}. 此外，还发现在 365 nm 激发下，560 nm 处的荧光增强被显着抑制，这一现象背后的机制已经通过实验和相关理论进行了探索。除了具有 0.7 nM LOD 的高选择性和检测灵敏度外，所制备的探针成功地证明了其在环境水样中 Hg ^{2+检测中的准确性。}此外，该探针可用于纸张传感器设计，并展示了一个准确可靠的基于手机的便携式平台，用于 LOD 为 1.9 nM 的 Hg ²⁺测定，表明其在即时检测应用中的潜力。