Rational design and characterization of high-efficiency planar A–π–D–π–A type electron donors in small molecule organic solar cells: A quantum chemical approach

• DOI: 10.1016/j.matchemphys.2014.02.027
• Publication Date: 2014-03-04T13:33:36Z
• Authors: Dongmei Wang; Weilu Ding; Zhiyuan Geng; Li Wang; Yun Geng; Zhongmin Su; Hailing Yu
• Keywords: Planarity testing; Electron donor

Abstract Taking the reported donor DR3TBDT as reference, a series of A–π–D–π–A type donor molecules involving different planar donor cores were designed and investigated by using density functional theory (DFT)/time-dependent DFT methods. Preliminary calculations on geometries, energy levels and spectrum properties show that four of the designed molecules ( 4 , 5 , 12 and 13 ) could become potential donor replacements of DR3TBDT due to their good planarity, larger light harvesting efficiencies and similar exciton migration capability. Additionally, several factors influencing on short-circuit current density ( J sc ) were analyzed by in-depth quantum chemical investigations on the transition density matrix, charge transfer indexes, exciton binding energy and Gibbs free energy loss in charge dissociation process. Comparative analyses demonstrate that 4 with indaceno[1,2- b :5,6- b ′]dithiophene donor core has more significant electron transfer character and favorable exciton dissociation capability for enhancing the J sc , and would be potentially promising donor material in organic solar cells.