A Simulation Study On Optical Performance Of PIN Type Organic Solar Cells

Because of the more and more serious energy and environment problem, solar energy has attracted considerable attention in recent years as a clean and renewable energy. Organic solar cells are attracting increasing attention because of their low environmental-load, flexibility, ease of fabrication and potential low cost. The absorption in thin film multilayer structures typically exhibits strong interference due to multiple reflection and transmission at the interfaces. Thus, the active layer absorption efficiency is functions of the optical properties of the materials employed, excitation wavelength, layer thickness, and the layer configuration. Fortunately, the interference can be modeled with simple and accurate methods, which could yield reliable information about the relationship between total optical absorption and the influence factors of it. The optical transfer-matrix theory, a powerful optical modeling tool, has been widely applied to simulate optical absorption and predict related electrical performance.In this paper, a theoretical model based on transfer matrix method and MATLAB computinf software were employed to investigate and optimize the properties of organic solar cells of different structures.First of all, optical simulations have been performed to investigate the optical properties of ITO/Zn Pc/C60/Al. The effects of thickness, varing incident wavelength on the optical performance of small molecular organic solar cells are studied theoretically. When the whole orgnic active layer thickness are 80 nm, 100 nm and 120 nm, the corresponding best thickness ratios of Zn Pc and C60 are 3:5, 11:9 and 7:5, respectively.Then the optical electric field distribution of ITO/P3HT:PCBM/Ag and PIN type of ITO/PEDOT:PSS/MEH-PPV:PCBM/n-C60/Li F/Al with varied incident wavelength are simulated. The effect of different mixing ratio, varing thickness and structure on the optical performance of polymer organic solar cells are studied. The study has shown that the optical electric field distribution with the varied incident wavelength. The device with mixing ratio 1.2:1 is better than the 1:1. The best thickness of P3HT: PCBM(1:1) is 210 nm. For PIN type which we studied with 40 nm thickness of intrinsic layer, achieve optimal optical electric fielddistribution. Compared with bulk heterojunction device, PIN type organic solar cells are more superior.Simulations reveal that excitation wavelength, layer thickness, mixing ratio and structure all have a certain degree of impact on the active layer absorption efficiency. The research of optical properties of organic solar cells provides a theoretical basis to the improvement of the energy conversion efficiency.