Dielectric resonators enhanced charge transfer in BNQDs–TiO₂/Cu₂O hybrid photo-electrode materials

Charge transfer dynamics in a hybrid of boron nitride quantum dots (BNQDs) and TiO₂/Cu₂O Mie resonators are studied. Three different sizes (d) (d = 10, 20, and 220 nm) of TiO₂ resonators were used to tune the Mie resonances. The hybrid of the largest-size Mie resonator and BNQDs shows the lowest charge transfer resistance, R_ct of 6.203 × 10⁴<i>Ω</i> and the highest current density of 2.05 μA/cm². The size-dependent photo-current density enhancement due to an increase in scattering from larger-sized TiO₂ confirms its role as the Mie resonator. The experimental results are supported by theoretical calculations of scattering, absorption, extinction cross-sections, and near-field enhancement due to the Mie resonators. This study will find potential applications in electro/photo-catalytic hydrogen production through water splitting.