A-D-A-Type Oligothiophenes for Small Molecule Organic Solar Cells: Extending the π-System by Introduction of Ring-Locked Double Bonds
A-D-A-Type Oligothiophenes for Small Molecule Organic Solar Cells: Extending the π-System by Introduction of Ring-Locked Double Bonds
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DOI：
10.1002/adfm.201404210
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发表时间：
2015-03-25
影响因子：
19
通讯作者：
Baeuerle, Peter
中科院分区：
文献类型：
--
作者：
Fitzner, Roland;Mena-Osteritz, Elena;Baeuerle, Peter
合成了一系列以1-（1，1-二氰亚甲基）-环己-2-烯（DCC）为受体的新型受体-供体-受体噻吩齐聚物。的结构，热，光电，和光伏性能的-扩展DCCnTs（n = 1-4）的特征和对比的趋势发现的一系列的母体二氰基乙烯基（DCV）取代的低聚噻吩DCVnT。光电性质揭示了额外的环外，空间固定的双键在反式构型的新型DCCnT衍生物的影响。一个密切的对应关系的衍生物具有相同数量的双键，即，DCCnTs和DCV（n + 1）Ts，被确定。尽管具有相同的能隙，但由于噻吩环相对于两个环外双键的芳构化能，DCC衍生物的前线轨道HOMO和LUMO的能级升高并且更不稳定，这表明供体强度提高并且受体强度降低。DCC-三噻吩作为真空处理的太阳能电池中的供体材料（功率转换效率4.4%）提供良好的光伏性能，明显优于所有可比较的DCV 4 T衍生物。
A series of novel acceptor-donor-acceptor oligothiophenes terminally substituted with the 1-(1,1-dicyanomethylene)-cyclohex-2-ene (DCC) acceptor has been synthesized. Structural, thermal, optoelectronic, and photovoltaic properties of the -extended DCCnTs (n = 1-4) are characterized and contrasted to the trends found for the series of parent dicyanovinyl (DCV)-substituted oligothiophenes DCVnT. The optoelectronic properties reveal the influence of the additional exocyclic, sterically fixed double bonds in trans-configuration in the novel DCCnT derivatives. A close correspondence for derivatives with equal number of double bonds, that is, DCCnTs and DCV(n + 1)Ts, is identified. Despite having the same energy gap, the energy levels of the frontier orbitals, HOMO and LUMO, for the DCC-derivatives are raised and more destabilized due to the aromatization energy of a thiophene ring versus two exocyclic double bonds indicating improved donor and reduced acceptor strength. DCC-terthiophenes give good photovoltaic performance as donor materials in vacuum-processed solar cells (power conversion efficiencies 4.4%) clearly outperforming all comparable DCV4T derivatives.