Theoretical Study Of Two Types Of New Solar Cell Materials

The economic development and the material standards of living of a country are largely depended upon the technologies and fuels that are available, and fossil fuel are the mainly energy source for humans as non-renewable energy source. However, the fossil fuels will be exhausted at the end of this century. To solve this problem, scientists around the world have been making large effort for finding new renewable energy, among these new renewable energy, solar energy has attracted more and more attention and become the most potential new energy because that it has many advantages such as endless origin, being free from pollution and not a safety hazard. So it has great significance to study solar cells, in our work, we made some investigation on Organic solar cell and Dye-sensitized solar cells and have gained some valuable research results.1. Theoretical Studies of Electron Transport Properties of ThCBM and [60JPCBMThe most widely used and promising polymer solar cell is based on a combination of poly(3-hexylthiophene)(P3HT) as the electron donor and [6,6]-phenyl C61butyric acid methylester ([60]PCBM) as the acceptor. To improve miscibility with P3HT,[6,6]-thienyl C61butyric acid methylester ([60]ThCBM), an analogue of [60]PCBM by replacing the phenyl group with a thienyl group, has been synthesized. Based on quantum chemistry calculations, we studied [60]ThCBM and [60]PCBM as potential solar cell materials. We calculated their molecular structure, reorganization energy, transfer integral, band structure and UV/Vis absorption spectrum. Semiclassical Marcus-Hush electron transfer theory is applied to predict the electron and hole mobility. All the transfer integral of possible hopping pathways of [60]ThCBM and [60]PCBM have been calculated, and the results show that [60]ThCBM is a promising acceptor material. The mobility of [60]ThCBM along the a axis is found to be1.16cm2V-1s-1, close to the experimental measurement (2±0.5cm2V-1s-1). The electron and hole mobility of [60]PCBM are found to be0.18cm2V-1s-1and1.49cm2V-1s-1respectively, displaying [60]ThCBM is ambipolar transport characteristics. Our investigations on C60,[60]PCBM and [60]ThCBM may provide useful detailed information for designing new fullerene derivatives as solar cell materials.2. Theoretical study on Zinc porphyrin derivatives sensitized solar cellsSince the first DSSCs were investigated by Gratzel and his co-workers in1991, many organic dyes with donor and acceptor unit were synthesized which were used to fabricate dye-sensitized solar cells. In order to get high-performance dye-sensitized solar cells, it is crucial to create effective organic dye sensitizers with the molecule structures which have good light-harvesting features and can provide good electron transfer between dyes and TiO2electrode. Recently, several studies have been reported on porphyrins as effective dye-sensitizers with good photovoltaic performance, however, it is easy for porphyrins dye-sensitizers to aggregate in the solutions. To solve this problem, porphyrins bearing alkoxyphenyl substituents at two of the four meso-positions were synthesized in recent. Based on the experiment results, we selected some typical Zinc porphyrin dye sensitizers to studied their molecular structure and electronic properties about photovoltaic performance in theory to find the direction to design new effective dye sensitizer molecules.