Inferring the molecular arrangements of boron subphthalocyanine chloride in thin film from a DFT/TDDFT study of molecular clusters and experimental electronic absorption spectra

Abstract

Abstract Thin-film morphology plays a critical role to influence the optical and electrical properties of organic solar cells. Therefore, exploring thin-film morphology of boron subphthalocyanine chloride is foremost for optimization of organic solar cells based on this donor material. Available experimental results suggest different molecular arrangements and organizations of subPC in the thin film of boron subphthalocyanine chloride, but their electronic absorption spectra are almost identical. To understand this disagreement, we model the different configurations of dimers and trimers of boron subphthalocyanine chloride, and run a series of calculations of density functional theory and time-dependent density functional theory with a polarizable continuum model in the present work. After making comparisons to available experimental results, our reproduced absorption spectra imply that it is not concave-to-concave or convex-to-concave but convex-to-convex configuration which is favorable in the solid state because only its simulated absorption peak is close to experimental data. In addition, our results show that convex-to-convex configuration is the best regarding photon absorption in the visible region.