N-I co-doped TiO2 compact film as a highly effective n-type electron blocking layer for solar cells

TiO2 film has attracted increasing interest due to its extensive applications in various solar cells. In this work, nonmetal N, I, and N-I co-doped TiO2 compact films have been used as electron blocking layers for dye-sensitized solar cells (DSSCs). The I-V test demonstrates that N-I co-doped TiO2 brings up a 17.67% increase of conversion efficiency with significant enhancements of both short circuit current density (Jsc) and photovoltage (Voc). By contrast, the N-doped TiO2 only improves Jsc and I-doped TiO2 only improves Voc. Such obvious effect created by the N-I co-doped TiO2 can be attributed to improved electron transport and restrained recombination of electron-hole pairs.