Solid polymer electrolyte dye-sensitized solar cells with organized mesoporous TiO₂ interfacial layer templated by poly(vinyl alcohol)–poly(methyl methacrylate) comb copolymer

An organized mesoporous TiO₂ interfacial layer (IL) with high porosity and good interconnectivity is prepared using a low-cost amphiphilic poly(vinyl alcohol)–poly(methyl methacrylate) (PVA–PMMA) comb copolymer template. Upon adding the Ti precursor, the absorption band of the PVA hydroxyl groups largely shift from 3305 to 3213 cm^{− 1}, and the average distance between the isolated PMMA domains increases from 53.7 to 55.6 nm, indicating selective interactions of the Ti precursor with the hydrophilic PVA main chains. The mesoporous TiO₂ IL with low roughness and high transparency enhances the light penetration into the photoanode and interfacial adhesion between the nanocrystalline TiO₂ and fluorine-doped tin oxide glass, improving the photocurrent of the fabricated dye-sensitized solar cells (DSSCs). The efficiency of the DSSC using the TiO₂ IL templated by PVA–PMMA with a solid polymer electrolyte reaches 5.5%, which is higher than those of DSSCs using TiO₂ ILs templated by PVA (4.9%), PMMA (4.2%), or no template (5.0%), indicating the effectiveness of PVA–PMMA comb copolymer as the template.