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.