Hydrogen Peroxide Involved Anodic Charge Transfer and Electrochemiluminescence of All-Inorganic Halide Perovskite CsPbBr3 Nanocrystals in an Aqueous Medium.

Reactive oxygen species (ROS) involved anodic charge transfer and electrochemiluminescence (ECL) of all-inorganic halide perovskite CsPbBr3 nanocrystals (NCs) were investigated in an aqueous medium with hydrogen peroxide (H2O2) as the model. CsPbBr3 NCs could be electrochemically oxidized to positively charged states by injecting holes onto the highest occupied molecular orbitals and could be chemically reduced to negatively charged states by injecting electrons onto the lowest unoccupied molecular orbitals by ROS. The charge transfer between CsPbBr3 NCs of oxidative and reductive states could bring out monochromatic ECL with onset around +0.8 V, maximum emission around 519 nm, and a full width at half-maximum around 20 nm. H2O2 could selectively enhance the anodic ECL of CsPbBr3 NCs, which not only opened a way to design a bioprocess-involved photovoltaic device with CsPbBr3 NCs but also was promising for color-selective ECL biosensing.