We develop an efficient fused-ring electron acceptor (ITIC-Th) based on indacenodithieno [3,2-b]-thiophene core and thienyl side-chains for organic solar cells (OSCs). Relative to its counterpart with phenyl side-chains (ITIC), ITIC-Th shows lower energy levels (ITIC-Th: HOMO = -5.66 eV, LUMO =-3.93 eV; ITIC: HOMO = -5.48 eV, LUMO =-3.83 eV) due to the a-inductive effect of thienyl side-chains, which can match with high-performance narrow-band-gap polymer donors and wide-band-gap polymer donors. ITIC-Th has higher electron mobility (6.1 X 10(-4) cm(2) V-1 s(-1)) than ITIC (2.6 X 10(-4) cm(2) V-1 s(-1)) due to enhanced intermolecular interaction induced by sulfur-sulfur interaction. We fabricate OSCs by blending ITIC-Th acceptor with two different low-band-gap and wide-band-gap polymer donors. In one case, a power conversion efficiency of 9.6% was observed, which rivals some of the highest efficiencies for single junction OSCs based on fullerene acceptors.
1.Peking Univ, Minist Educ, Key Lab Polymer Chem & Phys, Coll Engn,Dept Mat Sci & Engn, Beijing 100871, Peoples R China 2.Capital Normal Univ, Dept Chem, Beijing 100048, Peoples R China 3.Chinese Acad Sci, Inst Chem, Beijing 100190, Peoples R China 4.Beihang Univ, Sch Chem & Environm, Heeger Beijing Res & Dev Ctr, Beijing 100191, Peoples R China 5.Xi An Jiao Tong Univ, State Key Lab Mech Behav Mat, Xian 710049, Peoples R China 6.Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA 7.Georgia Inst Technol, Ctr Organ Photon & Elect, Atlanta, GA 30332 USA