Multiscale molecular simulations of the nanoscale morphologies of P3HT:PCBM blends for bulk heterojunction organic photovoltaic cells

• DOI: 10.1039/c1ee01508g
• Publication Date: 2011-08-11T10:30:30Z
• Authors: Cheng-Kuang Lee; Chun-Wei Pao; Chih-Wei Chu
• Keywords: Percolation (cognitive psychology); Surface-area-to-volume ratio; Charge carrier; Multiscale Modeling; Miscibility

In this study, we developed a multiscale molecular simulation framework including coarse-grained (CG) simulation, reverse-mapping, and morphology evaluation schemes to investigate the nanoscale morphologies of bulk heterojunction (BHJ) blend films comprising poly(3-hexylthiophene) (P3HT) methanofullerene derivative PCBM. A stable phase-separated film with fibrillar P3HT structure was observed after CG thermal annealing process, by reverse-mapping technique atomistic details—showing strong π–π interaction between thiophene rings—were retrieved. To evaluate P3HT:PCBM blends, spatial-discretization scheme developed. With such scheme, estimated average domain sizes, interface-to-volume ratios, percolation ratios blends at different weight ratios. The sizes determined through these simulations were in excellent agreement those reported experimentally. Moreover, our indicated that having close 1 : would have highest ratio most balanced charge carrier transport both PCBM phases, consistent experimental observation is optimal for blends. proposed herein can be extended investigating other photoactive layers organic photovoltaic cells.