Experimental and theoretical study of planar small molecule acceptor for organic solar cells

Abstract

A planar small molecule acceptor (IDTT-BO-MN) with 6,12-dihydro-dithieno[2,3-d:2′,3′-d']-s-indaceno[1,2-b:5,6-b']dithiophene (IDTT) as a central core, bis(alkoxy)-substituted benzene ring as conformational control moieties and malononitrile as end-capping units was designed and synthesized. Non-covalent interactions successfully controlled the rotation to make planar backbone. When IDTT-BO-MN was paired with cheapest polymer donor (P3HT), it achieved 5.75% power conversion efficiency and 9.06 × 10−4 cm2V–1S−1 electron mobility. A detailed quantum chemical analysis was performed to understand the electronic and structural behavior of synthesized acceptor. Non-covalent interactions were also studied through the analysis of partial atomic charges and binding energy between participating atoms. Transition dipole moment was calculated that can be simple descriptor for the short circuit current (Jsc). Molecular Packing behavior was also examined and intermolecular binding energy was calculated.