Polyaniline-Layered Rutile TiO₂ Nanorods as Alternative Photoanode in Dye-Sensitized Solar Cells

In this paper, dye-sensitized solar cell (DSSC) performance of the less explored polymorph of TiO₂, rutile, has been explored, and its performance has been modified with polyaniline (PANI) wrapping on the surface. For this purpose, highly crystalline rutile nanorods have been synthesized without any growth-directing substrates, employing a hydrothermal treatment. Further, to understand the phase composition and morphology, the synthesized nanorods and PANI-layered nanorods have been characterized through various physicochemical methods. The synthesized rods were implemented as photoanode material for DSSCs which exhibited a photoelectric conversion efficiency (PCE) of 4.28% with a high open-circuit voltage (V _OC) of 0.84 V which is highly superior to DSSC with Degussa P25 (PCE = 3.95%) TiO₂ nanoparticles. The resultant PCE of the nanorods was further enhanced to 6.23% on in situ deposition of PANI which acts as an electron-transporting layer. Introduction of conducting PANI over the rutile rod was explored as a new concept to improve the performance of photoanode material besides conventional TiCl₄ treatment or scattering layer deposition.