The Research Of Polymer Solar Cells Based On Fullerene Derivatives As Electron Acceptor Materials

Polymer solar cells have attracted many researchers because of their advantages, such as easy to fabricate, low cost, light weight and able to be processed into flexible devices. So far there are still many factors to limit development of polymer solar cells. In order to push the commercialization of polymer solar cells, it is necessary to improve power conversion efficiency, EQE response and stability of the devices. Recently donator material are obtained lots of study and has a range to be picked, while acceptor material receives less concentration, and the most common acceptor material is PC61BM. In this thesis, we studied the solar cells based on different acceptor materials. Here P3HT will be chosen as the donator.By analyzing the working principle and loss mechanism of polymer solar cells, we know polymer materials and morphology of organic film are the most important elements of device performance. So this thesis works on improving the devices performance. Firstly, we adopted different fullerene derivatives as acceptor materials which have a wider absorption spectrum and a higher LUMO level so as to enhance absorption, widen EQE spectrum response range and optimize A/D level structure.. Secondly, optimizing the morphology of active layer with different amount of additive thus improves the PCE. We got the conclusions as follows:1. Devices with PC71BM as acceptor material has a wider absorption spectrum,which results the enhances the photo current and the PCE.2. For the sake of looking for more efficient acceptor materials, new kind of fullerene derivatives with higher LUMO level such as ICBA and ICMA were used to improve the open circuit voltage significantly, resulting in a15%increase in PCE.3. In order to improve morphology of body heterojunction further, DIO was used as additive to mixed with chlorobenzene. DIO can change the phrase separation and morphology of P3HT mixed with fullerenederivatives. Those devices fabricated from CB solution with DIO additive show a huge improvement in short cut current, resulting in good device performance.