A Spot Ionogel for Visual Early-Warning of Illegal Lead Concentrations Coupling Inorganic Perovskite Crystallization and Photoluminescence

Lead halide perovskite solar cells still have potential lead leakage under the influence of natural forces, which has attracted widespread attention. In future large-scale applications, it is necessary to monitor and control the concentration of lead in the environment according to local laws and regulations. In this work, the coupling strategy of inorganic perovskite crystallization and photoluminescence is proposed for the first time to achieve the detection of lead in the environment. An easy-to-use, low-cost, and portable PVA/C(6)mimBr/CsBr ionogel (PCCI) device is prepared through solution process for on-site detection of Pb(II). The limit detection of PCCI is 236 mg kg(-1), which is close to and lower than the statutory standard of 250 mg kg(-1) in China's agricultural regulations, and is expected to achieve on-site early-warning. This work may promote the development of environmental early-warning devices in line with laws and regulations.