Study On The Performance Of Quantum Dots Sensitized TiO₂ Nanotubes Solar Cells

Since the beginning of the 21st century, with the rapid growth of global economy, people’s living standards have been greatly improved. Therefore the requirement for energy sources has grown up quickly. As a semiconductor phototube, solar cells can convert solar energy to electric energy, which has attracted increasing attention. Quantum dots sensitized TiO2 nanotubes solar cells has become research emphasis due to its advantages of low cost, larger extinction coefficients and the absorption spectrum adjustability.In the paper, highly ordered TiO2 nanotubes were grown on the Ti foils surface (99% purity) and then quantum dots were used to sensitize TiO2 nanotubes. The photo-anode materials were characterized by SEM, EDS, HRTEM, UV-vis, XRD, IPCE and Electrochemical Station. The contents of this paper are shown as follows.(1) CdS QDs are assembled into the TiO2 nanotubes in a one-step synthesis process. The maximum absorption peak edge of the CdS/TiO2 nonatubes has extended to 480 nm. With increased sensitization time, photoelectric conversion efficiency increased firstly and then decreased. When the sensitization time is 2 h, the photoelectric conversion efficiency is 0.83% which is five times that of non-sensitized TiO2 nanotubes.(2) The CdS:Eu3+/TiO2 photo-anode materials were prepared by direct adsorption. The biggest quantum efficiency and photoelectric conversion efficiency of CdS:Eu3+/TiO2 were 21% and 0.39% respectively when the sensitization condition was 4% doping Eu3+ concentration, sensitization temperature of 60 ℃, sensitization time of 8 h.(3) The PbS quantum dots deposited on TiO2 nanotubes via successive ion layer adsorption and reaction (SILAR). The TiO2 nanotubes loading with PbS quantum dots by 6 cycles were the optimal sensitization condition. Under the optimum conditions, the photoelectric conversion efficiency was 0.84%. Compared with graphite electrode, platinum electrode was more advantageous to improve the photoelectric properties of solar cells. Besides, the influences of electrolyte components were discussed in the paper. The results show that the photoelectric properties of solar cells can be improved by addition of K+ ion.(4) The TiO2 nanotubes loading with CdS and PbS quantum dots by 2 cycles were discussed in the paper. The results show that the photoelectric properties of solar cells will be greatly influenced by not only the types of quantum dots but also with the sedimentary sequence of quantum dots.