| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2018) | |
| Energy Harvesting & Storage | Wednesday Sessions |
| Session EH-WeM |
| Session: | Efficient Power Conversion/Cells |
| Presenter: | Satoshi Ishii, National Institute for Materials Science, Japan |
| Authors: | S. Ishii, National Institute for Materials Science, Japan S.L. Shinde, National Institute for Materials Science R.P. Sugavaneshwar, National Institute for Materials Science M. Kaur, National Institute for Materials Science T. Nagao, National Institute for Materials Science |
| Correspondent: | Click to Email |
Harvesting sunlight enables conversion of photon energy to electronic energy and thermal energy. Among different classes of materials, metals have unique properties in light harvesting. Since metals are highly conductive and do not have bandgaps, metals can generate hot carriers even with low energy photons to be injected into an adjacent semiconductor. The excited hot carriers eventually become heat and heat the metals themselves and their surroundings. These photoelectric and photothermal effects can be enhanced by the optical resonances i.e. surface plasmon resonances. Hence, number of researches have taken advantage of plasmon resonances in photoelectric and photothermal conversions. As gold and silver are known to be excellent plasmonic materials, nanostructures made of these noble metals have been widely used in the recent studies.
In contrast, we have been working with titanium nitride (TiN) nanostructure to show that it can also be used in photoelectric and photothermal conversions. Titanium nitride is chemically stable and much cost-effective than gold or silver, making it a practical choice of material. In addition, TiN is plasmonic in visible and near infrared and superior to gold and silver in absorbing broad spectrum. In the first part, we present that TiN nanostructures can generate photocurrent by the irradiation of visible light, and can enhance the visible photocatalytic activities of carbon nitride which is a UV-active metal-free photocatalyst. In the second part, we show that TiN nanoparticles are efficient sunlight absorbers to generate solar heat. Since each TiN nanoparticle act as a nanoscale heater, solar heated TiN nanoparticles offer efficient water distillation and chemical reactions such as oxidation of carbon monoxide. Our results demonstrate that TiN nanostructures have the potential to replace gold and silver nanostructures in sunlight harvesting applications with better efficiencies.