(Invited) Enhanced Water Splitting Under Modal Strong Coupling Conditions

Abstract

Metallic nanoparticles such as gold (Au) and silver (Ag) shows light absorption and scattering at the arbitrary wavelength of visible and near-infrared regions based on localized surface plasmon resonances (LSPRs). LSPRs which are collective oscillations of conductive electrons give rise to the enhancement of near-field and are expected as a light harvesting optical antenna for light energy conversion devices due to their spectrum tunability. We have successfully developed the plasmon-induced artificial photosynthesis systems such as water splitting and ammonia synthesis systems as well as solid-state plasmonic solar cells based on the principle of plasmon-induced charge separation between gold nanoparticles (Au-NPs) and the semiconductor photoelectrode.[1]-[6] Recently, the plasmon-induced charge separation has received considerable attention as a novel strategy for the solar energy conversion.[7],[8] However, for the monolayer of Au-NPs on the semiconductor in the regular Au-NPs loaded semiconductor photoelectrode, the insufficient absorption limited its solar energy conversion efficiency. Aiming at the enhancement of light absorption, in the present study, we apply the principle of modal strong coupling to plasmonic water splitting using Au-NPs/titanium dioxide (TiO2) thin-film/Au-film photoelectrode. [9] References Nishijima, K. Ueno, H. Misawa et al. J. Phys. Chem. Lett. 1, (2010)2031.Zhong, K. Ueno, Y. Mori, X. Shi, T. Oshikiri, K. Murakoshi, H. Inoue, H. Misawa, Angew. Chem. Int. Ed., 53 (2014)10350.Oshikiri, K. Ueno, H. Misawa, Angew. Chem. Int. Ed., 53, (2014)9802.Oshikiri, K. Ueno, H. Misawa, Angew. Chem. Int. Ed., 55, (2016) 3942.Nakamura, T. Oshikiri, K. Ueno, H. Misawa et al. J. Phys. Chem. Lett., 7, (2016) 1004.V. Hoang, K. Hayashi, K. Ueno, H. Misawa et al. Nat. Commun., 8, (2017)771.Ueno, T. Oshikiri, H. Misawa, ChemPhysChem, 17, (2016)199.Ueno, T. Oshikiri, Q. Sun, X. Shi, H. Misawa, Chem. Rev., 118, (2018) 2955.Shi, K. Ueno, T. Oshikiri, Q. Sun, K. Sasaki, H. Misawa, Nature Nanotech., 13, (2018) 953-958.