Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV16)
Publication date: 28th March 2016
Organic-inorganic metal halide perovskite materialshave the merits of high mobility and long carrier diffusion length for solar cell application. The PCE of perovskite solar cell is rapidly increased in the past five years to over 22%. In the device with p-i-n planar structure, PC61BM is usually used as an electron transporting material, which is a kind of solution processable fullerene derivative with high electron mobility. However, the current density of this kind of device is relatively low as compared with other kinds of structures. One of the key factors is that the electrons generated in the perovskite layer are difficult to be transported through the junction to the PC61BM layer. In this work, we provide a new approach by using fluorinated PC61BM as the electron transporting material to extract electrons from perovskite layer more effectively. Because fluorine atom has high electronegativity, we expect the fluorinated PC61BMwill have higher electron extraction ability. The devices using fluorinated PC61BM exhibit no hysteresis phenomenon. Their short current density and fill factor show significant enhancement without sacrificing the open circuit voltage. Therefore, the power conversion efficiency is increased. Besides, we also try to use different processing solvent to control the crystallization behavior of fluorinated PC61BM electron transporting layer. By optimizing the processing condition, the charge transport and PCE of the solar cell can be further improved.