Details

Autor(en) / Beteiligte

• Cheng, Yen-Ju
• Hung, Lung-Chang
• Cao, Fong-Yi
• Kao, Wei-Shun
• Chang, Chih-Yu
• Hsu, Chain-Shu

Titel

Alternating copolymers incorporating cyclopenta[2,1-b:3,4-b′]dithiophene unit and organic dyes for photovoltaic applications

Ist Teil von

• Journal of polymer science. Part A, Polymer chemistry, 2011-04, Vol.49 (8), p.1791-1801

Ort / Verlag

Hoboken: Wiley Subscription Services, Inc., A Wiley Company

Erscheinungsjahr

2011

Quelle

Wiley Online Library

Beschreibungen/Notizen

• We have synthesized six p‐type copolymers, CPDT‐co‐TPADCN, CPDT‐co‐TPADTA, CPDT‐co‐TPATCN, CPDT‐co‐DFADCN, CPDT‐co‐DFADTA, and CPDT‐co‐DFATCN, consisting of a cyclopenta[2,1‐b:3,4‐b′]dithiophene (CPDT) unit and an organic dye in an alternating arrangement. Triphenylamine (TPA) or difluorenylphenyl amine (DFA) units serve as the electron donors, whereas dicyanovinyl (DCN), 1,3‐diethyl‐2‐thiobarbituric acid, or tricyanovinyl (TCN) units act as the electron acceptors in the dyes. The target polymers were prepared via Stille coupling, followed by postfunctionalization to introduce the electron acceptors to the side chains. Because of the strongest withdrawing ability of TCN acceptor to induce efficient intramolecular charge transfer, CPDT‐co‐TPATCN and CPDT‐co‐DFATCN exhibit the broader absorption spectra covering from 400 to 900 nm and the narrower optical band gaps of 1.34 eV. However, the CPDT‐co‐TPATCN:PC71BM and CPDT‐co‐DFATCN:PC71BM based solar cells showed the power conversion efficiencies (PCEs) of 0.22 and 0.31%, respectively, due to the inefficient exciton dissociation. The DFA‐based polymers possess deeper‐lying HOMO energy levels than the TPA‐based polymer analogues, leading to the higher Voc values and better efficiencies. The device based on CPDT‐co‐DFADTA:PC71BM blend achieved the best PCE of 1.38% with a Voc of 0.7 V, a Jsc of 4.57 mA/cm2, and a fill factor of 0.43. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 We have synthesized six p‐type copolymers consisting of a cyclopenta[2,1‐b:3,4‐b′]dithiophene (CPDT) unit and an organic dye in an alternating arrangement. The absorption spectra, optical band‐gaps, and HOMO–LUMO energy levels of the conjugated polymers can be easily tailored by adjusting the electronic properties of the donor and the acceptor in the dye. Bulk heterojunction device based on CPDT‐co‐DFADTA:PC71BM blend achieved the best PCE of 1.38% with a Voc of 0.7 V, a Jsc of 4.57 mA/cm2, and a fill factor of 0.43.