Functional Multilayered Transparent Conducting Oxide Thin Films for Photovoltaic Devices

In this study, we present a thermally stable multilayered transparent conducting oxide (TCO) functionalized for dye-sensitized solar cells (DSSCs). Nb-doped TiO2 (NTO) layers deposited on conventional Sn-doped In2O3 (ITO) substrates using pulsed laser deposition (PLD) enhanced the optical-to-electrical conversion efficiency of the DSSCs by as much as 17% compared to that of bare ITO-based DSSCs. The electrical properties and J−V characteristics of the multilayered NTO/ITO films showed that the improved cell performance was due to the facilitated charge injection from TiO2 to ITO that resulted from the formation of an ohmic contact with ITO, as well as the conserved high conductivity of ITO after the oxidizing annealing process. Moreover, the NTO/ITO-based DSSC exhibited higher efficiency than a F-doped SnO2(FTO)-based one, which demonstrates that optimization of multilayered NTO-based TCOs is a realistic approach for achieving highly efficient photoenergy conversion devices.