Ultrafast Dynamics Group
Frédéric Laquai's Group

A spiro-bifluorene based 3D electron

A spiro-bifluorene based 3D electron acceptor with dicyanovinylene substitution for solution processed non-fullerene organic solar cells

A spiro-bifluorene based 3D electron acceptor with dicyanovinylene substitution for solution processed non-fullerene organic solar cells

D. Xia, D. Gehrig, X. Guo, M. Baumgarten, F. Laquai, and K. Müllen
J. Mater. Chem. A 2015, 3, 11086-11092. 
D. Xia, D. Gehrig, X. Guo, M. Baumgarten, F. Laquai, and K. Müllen
Electronic supplementary, Organic solar cells
2015
​A novel electron acceptor, namely 2,2′-(12H,12′H-10,10′-spirobi[indeno[2,1-b]fluorene]-12,12′-diylidene)dimalononitrile (4CN-spiro), exhibiting a three-dimensional molecular structure was synthesized and its thermal, photophysical, electrochemical, crystal, and photovoltaic properties were investigated. The novel acceptor exhibits excellent thermal stability with a decomposition temperature of 460 °C, an absorption extending to 600 nm, and a LUMO level of −3.63 eV. Solution processed bulk-heterojunction (BHJ) organic solar cells were fabricated using 4CN-spiro as an acceptor and polythieno[3,4-b]-thiophene-co-benzodithiophene (PTB7) as a donor polymer. The effect of the donor-to-acceptor ratio and processing conditions on the device performance was investigated. A device processed from tetrachloroethane with a donor to acceptor weight ratio of 1 : 1 yielded a power conversion efficiency (PCE) of 0.80%.