Increasing the Effciency of Organic Dye-Sensitized Solar Cells over 10.3% Using Locally Ordered Inverse Opal Nanostructures in the Photoelectrode

3D inverse opal (3D-IO) oxides are very appealing nanostructures to be integrated into the photoelectrodes of dye-sensitized solar cells (DSSCs). Due to their periodic interconnected pore network with a high pore volume fraction, they facilitate electrolyte in ltration and enhance light scattering. Nonetheless, preparing 3D-IO structures directly on non at DSSC electrodes is challenging. Herein, 3D-IO TiO2 structures are prepared by templating with self-assembled polymethyl methacrylate spheres on glass substrates, impreg- nation with a mixed TiO2:SiO2 precursor and calcination. The speci c surface increases from 20.9 to 30.7 m2 g−1 after SiO2 removal via etching, which leads to the formation of mesopores. The obtained nanostructures are scraped from the substrate, processed as a paste, and deposited on photoelectrodes con- taining a mesoporous TiO2 layer. This procedure maintains locally the 3D-IO order. When sensitized with the novel benzothiadiazole dye YKP-88, DSSCs containing the modi ed photoelectrodes exhibit an ef ciency of 10.35% versus 9.26% for the same devices with conventional photoelectrodes. Simi- larly, using the ruthenium dye N719 as sensitizer an ef ciency increase from 5.31% to 6.23% is obtained. These improvements originate mainly from an increase in the photocurrent density, which is attributed to an enhanced dye loading obtained with the mesoporous 3D-IO structures due to SiO2 removal.