Two Sizes CdSe Quantum Dots Co-sensitized TiO_2-Nano-SiO_2 Hybrid Photoelectrodes for Solar Cells Applications

摘要

The high-quality two sizes CdSe quantum dots (QDs) with nearly monodisperse size and shape were synthesized by the employed hot injection method with some modifications. The nanoparticles diameters were to be 2.6nm and 3.0nm respectively. To improve crystallization property and specific surface area of TiO_2 and to inhibit recombination processes of photoinduced electrons effectively, TiO_2-nano-SiO_2 hybrid films were prepared by adding proper meso-porous SiO_2 into TiO_2, in which the mass ratio of SiO_2 to TiO_2 was 5%. CdSe QDs were linked to TiO_2-nano-SiO_2 films using 3-mercaptopropionic acid to increase CdSe QDs adsorption. Two sizes CdSe QDs were achieved both to promote charge separation and to ensure the porper mobile pathway of free carriers. The J-V characterization showed that two sizes CdSe QDs co-sensitized TiO_2-nano-SiO_2 hybrid photoelectrodes had higher short circuit current density (J_(sc)) and open circuit voltage (V_(oc)), compared to one size CdSe QDs.