(Invited) Plasmon-Induced Charge Separation and Electric Field Localization

Abstract

Plasmon-induced charge separation (PICS) occurs at the interface between plasmonic nanostructures of Au, Ag, or Cu and a semiconductor (e.g., TiO2).1-3 Carrier transfer from the nanostructure to the semiconductor due to external photoelectric effects (including hot carrier injection) or interfacial electron transition is responsible for PICS.4 We reported PICS for the first time more than 10 years ago1,2 and studied its mechanisms4,5 and applications.1,3,6,7 In particular, we have reported effects of localized electric field on PICS. In the case of PICS-based oxidation of Ag nanoparticles, anodic reaction (i.e., oxidation of Ag to Ag+) occurs preferentially at the sites where optical near field is localized.8-10 This may be explained in terms of ejection of energetic holes from the nanoparticles as Ag+ ions.10 1. Y. Tian and T. Tatsuma, J. Am. Chem. Soc., 127, 7632 (2005). 2. Y. Tian and T. Tatsuma, Chem. Commun., 2004, 1810. 3. T. Tatsuma, Bull. Chem. Soc. Jpn., 86, 1 (2013) [account]. 4. E. Kazuma and T. Tatsuma, Adv. Mater. Interfaces, 1, 1400066 (2014). 5. H. Nishi and T. Tatsuma, Angew. Chem. Int. Ed., 55, 10771 (2016). 6. Y. Ohko, T. Tatsuma, T. Fujii, K. Naoi, C. Niwa, Y. Kubota, and A. Fujishima, Nat. Mater., 2, 29 (2003). 7. Y. Takahashi and T. Tatsuma, Appl. Phys. Lett., 99, 182110 (2011). 8. E. Kazuma, N. Sakai, and T. Tatsuma, Chem. Commun., 47, 5777 (2011). 9. I. Tanabe and T. Tatsuma, Nano Lett., 12, 5418 (2012). 10. K. Saito, I. Tanabe, and T. Tatsuma, J. Phys. Chem. Lett., 7, 4363 (2016).