LAUSR

Although there are many mechanistic studies for plasmon-induced charge separation (PICS), most of them have been devoted to energetic electron injection (or hot electron injection) from plasmonic metal nanoparticles into electron transport materials (ETMs) including n-type semiconductors. Here we also studied energetic hole injection (or hot hole injection) into five different organic hole transport materials (HTMs) with different ionization energies, by using solid-state photovoltaic cells fabricated by introducing gold nanoparticles (AuNPs) in between TiO2, which is an ETM, and a HTM. As a result, photocurrents based on PICS are obtained even if the height of the energy barrier at the Au–HTM interface is 0.9 eV. Therefore, the present PICS processes involve both energetic electron injection from AuNPs to TiO2 and hole injection from AuNPs to the HTMs. In this case, simultaneous electron–hole injection, in which one electron–hole pair gives simultaneous electron injection into TiO2 and hole injection int...