TY - JOUR
T1 - Synthesis and photovoltaic effect in red/near-infrared absorbing A-D-A-D-A-type oligothiophenes containing benzothiadiazole and thienothiadiazole central units
AU - Luponosov, Yuriy N.
AU - Min, Jie
AU - Khanin, Dmitry A.
AU - Baran, Derya
AU - Pisarev, Sergey A.
AU - Peregudova, Svetlana M.
AU - Dmitryakov, Petr V.
AU - Chvalun, Sergei N.
AU - Cherkaev, Georgiy V.
AU - Svidchenko, Evgeniya A.
AU - Ameri, Tayebeh
AU - Brabec, Christoph J.
AU - Ponomarenko, Sergei A.
N1 - Publisher Copyright:
© 2015 Society of Photo-Optical Instrumentation Engineers.
PY - 2015/1/1
Y1 - 2015/1/1
N2 - Two π-conjugated acceptor-donor-acceptor-donor-acceptor-type (A-D-A-D-A) oligothiophenes, TT-(2T-DCV-Hex)2 and BT-(2T-DCV-Hex)2 were designed and synthesized with thienothiadiazole (TT) or benzothiadiazole (BT) as the core and dicyanovinyl (DCV) as the terminal acceptor groups for comprehensively investigating and understanding structure-property relationships. The resulting oligomers were first characterized by thermal analysis, UV-Vis spectroscopy, and cyclic voltammetry. By simply changing the BT to TT core in these two oligothiophenes, the highest occupied molecular orbital levels were varied from-5.55 eV for BT-(2T-DCV-Hex)2 to-5.11 eV for TT-(2T-DCV-Hex)2, and the optical band gaps were varied from 1.72 eV for BT-(2T-DCV-Hex)2 to 1.25 eV for TT-(2T-DCV-Hex)2, ascribed to the stronger electron accepting character of the TT core. However, the power conversion efficiency of bulk heterojunction organic solar cells (OSCs) with TT-(2T-DCV-Hex)2 as donor and [6,6]-phenyl C70-butyric acid methyl ester (PC71BM) as acceptor was measured to be 0.04% only, which is much lower than that of BT-(2T-DCV-Hex)2:PC71BM (1.54%). Compared to the TT-(2T-DCV-Hex)2 system, the BT-(2T-DCV-Hex)2 based device shows smoother film surface morphology, and superior charge generation and charge carrier mobilities. Therefore, the results clearly demonstrate that in addition to modifying the alkyl side chains and p-bridge lengths, the design of new small molecules for high-performance OSCs should also aim to choose suitable acceptor units.
AB - Two π-conjugated acceptor-donor-acceptor-donor-acceptor-type (A-D-A-D-A) oligothiophenes, TT-(2T-DCV-Hex)2 and BT-(2T-DCV-Hex)2 were designed and synthesized with thienothiadiazole (TT) or benzothiadiazole (BT) as the core and dicyanovinyl (DCV) as the terminal acceptor groups for comprehensively investigating and understanding structure-property relationships. The resulting oligomers were first characterized by thermal analysis, UV-Vis spectroscopy, and cyclic voltammetry. By simply changing the BT to TT core in these two oligothiophenes, the highest occupied molecular orbital levels were varied from-5.55 eV for BT-(2T-DCV-Hex)2 to-5.11 eV for TT-(2T-DCV-Hex)2, and the optical band gaps were varied from 1.72 eV for BT-(2T-DCV-Hex)2 to 1.25 eV for TT-(2T-DCV-Hex)2, ascribed to the stronger electron accepting character of the TT core. However, the power conversion efficiency of bulk heterojunction organic solar cells (OSCs) with TT-(2T-DCV-Hex)2 as donor and [6,6]-phenyl C70-butyric acid methyl ester (PC71BM) as acceptor was measured to be 0.04% only, which is much lower than that of BT-(2T-DCV-Hex)2:PC71BM (1.54%). Compared to the TT-(2T-DCV-Hex)2 system, the BT-(2T-DCV-Hex)2 based device shows smoother film surface morphology, and superior charge generation and charge carrier mobilities. Therefore, the results clearly demonstrate that in addition to modifying the alkyl side chains and p-bridge lengths, the design of new small molecules for high-performance OSCs should also aim to choose suitable acceptor units.
KW - Donor-acceptor oligomer
KW - benzothiadiazole
KW - charge carrier mobility
KW - charge generation
KW - dicyanovinyl group
KW - organic solar cell
KW - thienothiadiazole
UR - http://www.scopus.com/inward/record.url?scp=84923171882&partnerID=8YFLogxK
U2 - 10.1117/1.JPE.5.057213
DO - 10.1117/1.JPE.5.057213
M3 - Article
AN - SCOPUS:84923171882
SN - 1947-7988
VL - 5
JO - Journal of Photonics for Energy
JF - Journal of Photonics for Energy
IS - 1
ER -
