Research on the Characteristics of Organic Solar Cells

Recently, organic solar cells are attracting a lot of attention due to flexibility, low cost, light weight and large-area applications, and significant improvement in the power conversion efficiency. But the efficiencies of organic solar cells are still lower than crystal silicon solar cells. By studying the photovoltaic properties of organic solar cells it is possible to influence the short circuit current (I_sc), the open circuit voltage (V_oc), the fill factor (FF), hence the cells efficiencies can be improved. First of all, the paper describes the characteristics of organic solar cell. Several characteristics impact on the conversion efficiency of organic solar cells, including the series resistance (R_s), the shunt resistance (R_sh) and so on. A circuit model of the solar cell provides a quantitative estimate for losses in the solar cell to interpret the characteristics of the solar cell. The conventional circuit model which is suitable for inorganic solar cells has emerged. However, compared with inorganic solar cells, organic solar cells are lack of a three-dimensional crystal lattice, different intramolecular and intermolecular interactions, local structural disorders, amorphous and crystalline regions, and chemical impurities. Therefore, an appropriate circuit model is represented in the paper.