Mitigation of Surface Aggregation in Modified Phthalocyanines as Potential Photo Sensitizers

摘要

Important to the development of dye-sensitized solar cells is the longevity and photo-conversion efficiency of the dye. To improve cost effectiveness, dyes of superior thermal and chemical stability are desirable to extend device performance. In this study, we examine a series of peripherally fluorinated Zinc-Phthalocyanines (F_xZnPc). Introduction of chemically inert fluorine and isopropyl fluoroalkyl groups on the periphery of the Pc improve the dye stability and allow for tunable photo-physical properties. Additionally, introduction of the bulky isopropyl fluoroalkyl groups help mitigate molecular aggregation in thin films which is known to be detrimental to maintaining the desired photo-physical properties of the surface coating. Using molecular dynamics and first principles modeling, various substituent effects on surface adhesion and aggregation over TiO_2 surfaces are characterized for both symmetric and asymmetric Substitution.