Solar Water Splitting Photoelectrodes Utilizing Oxide 2-Dimensional Electron Gas and Plasmonic Nanoparticles

The solar water splitting is the third generation of solar energy utilizing technology for future energy problem. Through the past years, the technology has been amazingly meliorated, and theoretical basis has been enormously progressed. In recent days, much endeavor has been dedicated to enhancing solar water splitting efficiency. For further improvement, we need to deeply reflect a perspective of charge generation and transport in photoelectrodes and at interfaces between the electrodes and water. One of the most appropriate strategy for this concept would be grafting plasmonics to the photoelectrodes gernally based on oxide semiconductors. If we put plasmonic nanoparticles onto the surface of oxide semiconductors, the photoactivity of the electrodes can be improved by the three mechanisms ; direct electron transfer of hot electrons (DET), local electromagnetic field enhancement (LEMF), and resonant energy transfer (RET). In this reason, revealing the interaction of plasmonic nanoparticles with 2-dimensional electron gas (2DEG) interface which has huge amount of charge in the interface and extremely high mobility would be very interesting. In this talk, we present photoelectrochemical properties of LaAlO₃/SrTiO₃ 2DEG system with plasmonic nanoparticles. Our results clearly reveal the substantial enhancement of photoactivity in SrTiO3 by incorporating 2DEG interface and plasmonic nanoparticles, suggesting the synergetic effect of 2DEG and plasmon for enhaced photoactivity of oxide-based solar water splitting photoelectrodes.