CsPbBr perovskite quantum dots/ZnO inverse opal electrodes: photoelectrochemical sensing for dihydronicotinamide adenine dinucleotide under visible irradiation.

All-inorganic perovskite quantum dots (PQDs) have attracted tremendous attention due to their extraordinary optical properties, especially CsPbBr3 QDs with their high stability and photoluminescence efficiency. However, studies investigating the biosensing capabilities of PQDs are still limited. In this work, we designed a visible -light-triggered photoelectrochemical (PEC) sensor based on CsPbBr3 QDs for the first time. The immobilized three-dimensional (3D) ZnO inverse opal photonic crystals (IOPCs) were applied to dihydronicotinamide adenine dinucleotide (NADH) sensing. It was found that the CsPbBr3 QDs, as a photoactive material in a PEC sensor, can expand the photocurrent response of the PEC sensor to the visible region, as well as boost its conductivity. This PEC sensor based on a ZnO/CsPbBr3 electrode demonstrates sensitive detection of NADH in phosphate buffer saline solution and serum, with a good linear range from 0.1 μM to 250 μM and a low detection limit of 0.010 μM. Our strategy offers a new approach to perovskite QD-based PEC sensing, which could be more sensitive and convenient for clinical analysis.