Investigation Of Optical Spacer And Inverted Architecture In Organic Solar Cells

In recent years, all the nations have being facing an important trouble which is energy. Increasing applications of renewable energy in various fields is one of the most effective way to solve energy problem. Because solar energy has the characteristics that are not only inexhaustible and clean, but also safe in use, the development of solar energy has being focused. Using solar energy is to convert solar energy into electric energy. This is mainly done by solar cells. Organic solar cells have attracted much attention because of their low-cost, light weight and flexibility. Thereby, the research of organic solar cells has been becoming a hotspot.Firstly, in the fundamental structure of organic photovoltaic cells which is based on CuPc and C6o, the insertion of Cul between ITO(indium-tin oxide) and CuPc has a significant improvement in the short-circuit and fill factor. Cul is used to improve the molecular orientation of CuPc to absorb more light and modify the anode. Efficiency of organic solar cells is enhanced by using CuI as buffer layers. Moreover, the thickness of CuPc and C60play an important role to enhance the properties of OP Vs. And we optimized the thickness of every material which is used in the organic solar cells in this experiment. As a result, this strategy has improved the power conversion efficiency to1.56%. The thickness of the every layer is important to the device improvement.Secondly, we research the organic solar cells based on small molecule which is blending donor(CuPc) and acceptor(C60) materials. It means that joining the mixing layer between the donor and acceptor. The mixed layer is made up of donor and acceptor materials according to certain proportion (usually the mixing ratio is1:1).By experimental analysis, we find the optimal thickness of the mixing layer(CuPc:C6o)is15nm,when the thickness of CuPc and C60is12.5nm,32.5nm,respectively.In this condition, the separated efficiency of exciton is best, and the recombinated efficiency of electron and hole is lowest, and the electrons and holes can transport well. We further analyze the effect of optical spacer on the properties of organic small molecule solar cells. The insertion of C6o:LiF(3:1) as optical spacer between C60and Al(Aluminum)has a significant increasement in the light absorption of the device, improving the device efficiency.Lastly, we studied the inverted architecture of organic solar cells based on small molecules. We use the ITO electrode as cathode, and metal electrode which is provided with high work function or nonmetal electrode as anode. It is obvious that Al with proper thickness as electron-injection layer enhance the performance of photovoltaic cells. However, thick Al will affect the absorption of solar light in these devices. And the effect when Al is exposed the atmosphere for a period of time will be better. That’s because the generation of AlOX will further reduce the work function of electrode and the potential barrier of the cathode. Through the inverted structure, we analyze the characteristics of BCP.