Cu2ZnSnS4 Nanoparticle Sensitized Metal-Organic Framework Derived Mesoporous TiO2 as Photoanodes for High-Performance Dye-Sensitized Solar Cells

We present a facile hot injection and hydrothermal method to synthesize Cu2ZnSnS4 (CZTS) nanoparticles sensitized metal organic frameworks (MOFs)-derived mesoporous TiO2. The MOFs-derived TiO2 inherits the large specific surface area and abundantly porous structures of the MOFs structure; which is of great benefit to effectively enhance the dye loading capacity, prolong the incident light traveling length by enhancing the multiple interparticle light-scattering process; and therefore improve the light absorption capacity. The sensitization of CZTS nanoparticles effectively enlarges the photoresponse range of TiO2 to the visible light region and facilitates photoinduced carrier transport: The formed heterostructure between CZTS nanoparticles and MOFs-derived TiO2 with matched band gap structure effectively suppresses the recombination rates of photogenerated electron/hole pairs and prolongs the lifespan of the carriers. Photoanodes based upon CZTS/MOFs-derived TiO2 photoanodes can achieve the maximal photocurrent of 17.27 mA cm(-2) and photoelectric conversion performance of 8.10%, nearly 1.93 and, 2.21 times higher than those of TiO2-based photoanode. The related mechanism and model are investigated. The strikingly improved photoelectric properties are ascribed to a synergistic action between the MOFs-derived TiO2 and the sensitization of CZTS nanoparticles.