Enhanced photovoltaic and carrier collection efficiency of dye sensitized solar cell: Nb2O5 coated TiO2 photoanode

Abstract

ABSTRACTDye sensitized solar cells (DSSCs) were fabricated using Nb2O5 energy barrier layer is coated on the TiO2 photoanode. This energy barrier (Nb2O5 layer) reduces the recombination rate of the photoinjected electrons with their counter holes. A monoclinic Nb2O5 energy barrier layer can be coated 1 and 3 times on a TiO2 photoanode using a dip-coating method. The Nb2O5/TiO2 photoanode exhibits enhanced photovoltaic performance, which is better than the bare TiO2 photoanode. The results presented in this study show that this Nb2O5 layer forms an inherent energy barrier at the electrode-electrolyte interface. The electron transport and charge recombination behaviors of DSSCs were investigated by electrochemical impedance spectra (EIS) and the results illustrated that the DSSCs showed the lowest charge transport resistance and the longest electron lifetime. The electron transport and recombination were studied by stepped light- induced transient measurements of photocurrent and voltage (SLIM-PCV) method and shown that the electron diffusion length is increasing with the Nb2O5 coating.