Why can fluorine-substituted conjugated polymers improve the efficiency of organic solar cells?
Today, with the increasing consumption of energy, research on solar cells has attracted more and more attention. Compared with familiar silicon solar panels, organic solar cells are softer, lighter and easier to process. How to improve the efficiency of organic solar cells is a hot topic in recent years. Numerous studies have shown that fluorine-substituted polymers can improve the efficiency of organic solar cells. The research group of the Department of Chemistry of the University of North Carolina at Chapel Hill recently published a fluorine-substituted conjugated polymer property and organic solar energy at the Accounts of Chemical Research. A review of the impact of battery efficiency.
As a donor material in the active layer of an organic solar cell, the chemical structure of the polymer determines its properties, which in turn affects the efficiency of the organic solar cell. In related research, this review selected some representative articles that systematically studied the effects of fluorine substitution, and summarized the effects of fluorine substitution on the polymer properties of different structures and organic solar cells. In general, fluorine substitution can effectively affect the energy level of polymers, the interaction between polymers, and the microscopic morphology of active layers of organic solar cells, all of which are closely related to the efficiency of organic solar cells. In this review, the authors focus on the analysis of the position of the fluorine substitution: when the fluorine atom is placed in the electron-deficient structural unit, the efficiency of the organic solar cell can generally be effectively Raise; but if the fluorine atom is placed in the electron-donating structural unit, there are results indicating that the efficiency of the organic solar cell can be improved, and studies have shown that this substitution method causes the solar cell efficiency to decrease. By analyzing the main fluorine-substituted structural units, the authors found that regardless of whether the fluorine is placed in the electron-deficient or electron-donating structural unit, the chemical structure of the polymer itself will have a greater impact on the effect of fluorine substitution, and the efficiency of the solar cell will increase. The reason behind (or lowering) will also change due to the chemical structure of the polymer.