有机活性材料的低载流子迁移率使得有机光伏电池的电极收集到的电荷较少。增加活性层光吸收能够增加激子的产生数从而增加电极收集到的电荷, 提升器件的性能。通过对器件模拟的方法, 研究以P3HT∶PCBM为活性层的薄膜太阳能电池的光学性能。 在此基础上, 提出采用镀多层高反射膜的方法改善电池器件的光学性能。结果表明: 活性层厚度对电池器件的光吸收起到主导作用; 镀多层高反射膜在活性层厚度小于160 nm、Ag厚度小于20 nm时能大幅度改善电池器件的光学性能, 光生激子总数随活性层厚度的增加而迅速增多, 并且在活性层厚度约为150 nm时为一个最佳值。

Low carrier mobility of organic materials limits the number of carriers extracted by electrodes. By increasing light absorption in the active layer, more excitons could be produced so as to increase current which extracted by electrodes. And the performance would be improved by this way. Photoelectric field distribution and excitons generated in P3HT∶PCBM active layer were studied by the numerical modeling method. Based on it, the method of coating multilayer high reflectance films behind the cathode was proposed. Simulations reveal that the thickness of active layer plays a leading role in optical absorption. When the thickness of active layer is less than 160 nm and the thickness of Ag is less than 20 nm, coating multilayer high reflectance films could improve the optical performance of solar cells largely. Excitons increase fast with the thickness of active layer, and the number of excitons reaches an optimal value when the thickness of active layer is about 150 nm.