Control of interfacial charge-transfer interaction of dye and p-CuI in solid-state dye-sensitized solar cells

We systematically investigated the photovoltaic and absorption characteristics of solid-state dye-sensitized solar cells with CuI to elucidate the impact of the interaction between the dye and CuI. For the ruthenium complex N719, the incident photon-to-current conversion efficiency (IPCE) on the longer-wavelength side decreased owing to the change of the metal-to-ligand charge transfer (CT) of N719 due to the interaction between the thiocyanate groups of N719 and CuI. In contrast, when D149-which included rhodanine groups-was used, the interaction with CuI and the resultant CT increased the IPCE. The results provide a new strategy for improving the photovoltaic performance by controlling the interfacial CT between the dye and CuI. (C) 2017 The Japan Society of Applied Physics