Plasmon-Induced Charge Separation at Ag/p-NiO Nanocomposites for Solid-State Photodetectors

All-solid-state photoelectric conversion cells were fabricated, consisting of silver nanoparticles exhibiting localized surface plasmon resonance (LSPR) and NiO, which is a p-type semiconductor. When light is irradiated at the LSPR wavelength, positive charge transfer occurs from the silver nanoparticles to the NiO side, resulting in plasmon-induced charge separation (PICS) and an anodic photocurrent. This cell has an extremely simple structure that does not require electrolytes or other charge transport layers and has high long-term stability in air due to the use of highly stable gold as the counter electrode. The maximum incident photon-to-current efficiency value is 0.054%, which is the highest value currently available for PICS systems using plasmonic nanoparticles and p-type semiconductors in the case without any bias applied. These technologies are expected to be applied as advanced mechanisms in photodetectors. In particular, the simple, all-solid-state configuration without the need for electrolytes or charge transport layers offers significant advantages in terms of device fabrication, long-term stability, and miniaturization. Moreover, the bias-free operation and tunable spectral response enabled by plasmonic resonance make this system a promising candidate for practical use in low-power, wavelength-selective photodetectors.