Theoretical And Experimental Studies On Polymer Solar Cells

Polymer solar cells are by far characterized of low-cost raw material, simple process and being produced in large area. Meanwhile, the advent of various increasing mature methods of making process for polymer film is a beneficial guarantee for the production of polymer solar cells. Therefore, the polymer solar cells become one of the heat pots of present research area.With the purpose of enhancing the transformation efficiency of photovoltaic devices, an intensively exploration has been made on the mechanism and experiment study of polymer solar cell and some new results has been achieved.This paper, starting with the optimization of the mechanism of polymer solar cells, researches the process of optic-electric transformation and loss mechanism, simulates the output properties of organic solar cell, optical absorption, and charge carriers transport by Matlab, then makes the polymer solar cells based on the complex of P3HT/PCBM and MDMO-PPV/PCBM, carries out the experiment, discovers the proper proportion of donor and acceptor and solvent and founds device annealing and spinning interlayer are the important ways to enhance the performance of polymer solar cells.To imitate the influence of organic solar cell, mechanism and equivalent circuit of organic solar cell were analyzed and the computer simulation mode on properties of organic solar cell was established. We prepared bulk heterojunction organic solar cells, and the comparison showed that there was coincidence between the results of simulation and experiment.Based on optical interference and carrier transport principle, we propose models of the organic polymer bulk heterojunction photovoltaic cells. The functional relation of exciton generation rate, carrier densities and short circuit current densities versus the depth of the film has been simulated and analyzed, and the model is validated by experiment. We demonstrate that model can be useful for the organic photovoltaic cells with high power conversion efficiency.Above all, this paper for the first time investigates the polymer solar cells both in theory and in experiments from a new perspective. Theoretically, equivalent circuit of organic solar cell, models of incoherent optical absorption and charge carriers transport, simulation system of output properties of organic solar cells, were established according to the optical principle and diffusion theory; experimentally, the effect on solar cell's conversion efficiency of proportion of donor and acceptor,solvent select , device annealing and spinning interlayer have been systematically researched. The result is both practical and learned with high value.The research shows that the different proportion of donor and acceptor changed device's open circuit voltage and short circuit current, improved performance of devices. Solvent select also changed film's microstructure and improve organic solar cells' performance. We have studied the effect of thermal annealing on the performance of bulk heterojunction solar cells. We explain the observed trends in device characteristics in terms of differences in the film morphology. Thermal annealing provides interfaces and pathways for charge transfer, and to maximize the photo-induced charge separation, improving power conversion efficiency of polymer solar cells. The effect of spin-casting interface buffer layer on the performance of Donor/Acceptor bulk hetero-junction organic polymer photovoltaic cells was studied in this paper. Comparing the devices with and without buffer layer, the open-circuit voltage and short-circuit current of the device with buffer layer were influenced, and the solar cell's conversion efficiency was improved as well.