Dye-sensitized solar cells based on visible-light-active TiO2 heterojunction nanoparticles

•Synthesis of S,N doped TiO2 nanoparticles (0.2 TU-TiO2 at 600 °C and 800 °C) and pure TiO2.•Synthesis and characterization of S,N doped TiO2 nanoparticles and pure TiO2.•Fabrication of DSSC with pure TiO2 and S,N doped TiO2.•Bandgap value reduces.•Comparison of pure TiO2 and S,N doped TiO2 nanoparticles in visible light.

Dye-sensitized solar cells (DSSCs) have been fabricated based on visible-light-active titanium oxide (TiO2) heterojunction nanoparticle. DSSCs are purely based on both UV light-active anatase TiO2 photocatalyst and a visible-light-active dye. The main drawback of pure anatase TiO2 absorbance in the visible-light is inactive and the same is nullified while using visible-light-active TiO2 heterojunction nanoparticles. The photoinduced charge carrier recombination is also high in single-phase TiO2 photocatalysts. One of the solutions for this problem is the use of anion-doped TiO2 heterojunction nanostructures (anion for bandgap tuning and heterojunction for reducing charge carrier recombination). The main problem is synthesis of this kind of nano-heterojunction at low temperatures (<700 °C) to get good surface area and small particle size. To overcome these problems, in the present study, anion-doped TiO2 heterojunction has been synthesized at 600 °C for DSSC fabrication and characterized comprehensively. Anion-doped TiO2 has the capability to absorb visible light in the spectrum, so this can be applied to enhance solar cell fabrication.