Fabrication of three-dimensionally ordered macroporous TiO₂ film and its application in quantum dots-sensitized solar...

Engineering of TiO₂ photoanode is an important strategy for increasing the photovoltaic conversion efficiency of quantum dots-sensitized solar cells (QDSSCs). In this work, three-dimensional ordered macroporous (3DOM) TiO₂ films are fabricated by the controlled infiltrating-calcination method using the close-packed polystyrene spheres colloidal crystals as templates. The as-prepared macroporous TiO₂ films are then applied as the photoanode in colloidal CdSe QDSSCs. This structure not only facilitates the penetration of thioglycolic acid capped CdSe QDs, and thus achieving a high coverage of the internal surface with QDs sensitizer, but also exhibits a photonic band gap with tunable positions, which could enhance the light absorption. As a result, the liquid-junction QDSSCs assembled with the CdSe sensitized 3DOM TiO₂ yields a power conversion efficiency of 3.60% under solar illumination of 100 mW cm^-2, and this value is much higher than that of the device using nanoporous TiO₂ photoanode (1.82%). Our results indicate that the 3DOM TiO₂ is a promising candidate for the construction of high-efficiency QDSSCs.