One-step process for the synthesis and deposition of anatase, two-dimensional, disk-shaped TiO₂ for dye-sensitized solar cells

We report a one-step process for the synthesis and deposition of anatase, two-dimensional (2D), disk-shaped TiO₂ (DS-TiO₂) using titanium isopropoxide (TTIP), ethyl cellulose (EC), and solvents. The planar structure of EC plays a pivotal role as the sacrificing template to generate the 2D disk-shaped structure with a thickness of 1.5-3.5 μm, while a disk-like structure was well developed in the tetrahydrofuran (THF)/toluene mixed solvent. The quasi-solid-state dye-sensitized solar cells (qssDSSCs), fabricated with a nanogel electrolyte and a DS-TiO₂ layer on a nanocrystalline (NC)-TiO₂ photoanode, showed an energy conversion efficiency of 5.0% without any TiCl₄ post-treatment, which is higher than that fabricated without DS-TiO₂ (4.2%). When utilizing a poly((1-(4-ethenylphenyl)methyl)-3-butyl-imidazolium iodide) (PEBII) as the solid electrolyte, a high efficiency of 6.6% was achieved due to the combination of high mobility PEBII and a bifunctional DS-TiO₂ layer with a 2D structure and anatase phase. The bifunctionality of the DS-TiO₂ layer allows greater light scattering back into the device and provides additional surface area for improved dye adsorption, resulting in short circuit current density (J_sc).