| The organic photovoltaic cells (OPV) have gained considerable attention due to their merits of lower production costs, convenient design/synthesis of new materials, enables flexible substrate based roll-to-roll process, wide applications, simple device structure and transparent. Recent goal in organic photovoltaic cells study is to improving the power convertion efficience and stability thus to realize commercial application and to benefit our life.This thesis focuses on the mechanism of small molecule organic bulk hetero junction devices and experiments in order to increase the power conversion efficiency.Firstly, organic bulk hetero junction devices based on CuPc:C60as active layer were studied and the optimal blend ratio was found. We analyze the inner mechanism of effection of different blend ratio on the performance of photovoltaic devices by investigating the morphology and electron absorption activities of active layer. We found that when the mixing ratio of CuPc:C60was3:1the phase separation phenomenon were observed and segerigation network were formed. At the same time, by comparing the hole mobility of active layers we further explained the reason of device performance changing.Secondly, we synthesized a p-type organic semiconductor material HPCzI and investigated its structure and properties. Based on the research results of first part, we studied the efficiency of the material as anode buffer in the former optimized bulk heterojunction OPV devices. And compared with MoO3and CuPc anode buffer layer, the HPCzI showed its superiority as anode buffer. In addition, the HPCzI had been doped with MoO3in different ratio to form anode buffer layer in OPV devices lead to an improved device performance. And we found that different MoO3doping ratio in anode buffer leaving a big impact on device performance. |
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