Molecularly imprinted polymers and PEG double engineered perovskite: an efficient platform for constructing aqueous solution feasible photoelectrochemical sensor

Herein, a kind of dual polymers, molecularly imprinted polymers (MIPs) and polyethylene glycol (PEG), coated perovskite (MIP-PEG/CH 3 NH 3 PbI 3 ) was synthesized and used to construct a photoelectrochemical (PEC) sensor for salicylic acid (SA) detection. A selective MIP layer for SA recognition was anchored on the PEG modified CH 3 NH 3 PbI 3 through a facile UV-polymerization process. PEG benefits the water-resistant ability of CH 3 NH 3 PbI 3 and MIPs endows the photoactive CH 3 NH 3 PbI 3 good selectivity. Thanks to the protection from PEG and MIPs, the MIP-PEG/CH 3 NH 3 PbI 3 product showed stable photocurrents in aqueous solution. Furthermore, methylammonium iodide (MAI) contained electrolyte was used in which MAI could restore the degraded part of CH 3 NH 3 PbI 3 to improve its stability. SA was detected by monitoring the photocurrent signal changes of the PEC sensor resulting from the reaction between SA and MIPs. The as-fabricated PEC sensor showed good performance in terms of sensitivity and selectivity. The linear range between the photocurrent changes and the concentrations of SA was from 1.0 × 10 -15 to 7.0 × 10 -11 M. This work unveiled the promise of organic-inorganic hybrid lead halide perovskite based structure for PEC sensors and inspired more interests in the development of diverse perovskite-based materials for advanced PEC analysis.