Tuning the electronic coupling in a low-bandgap donor-acceptor copolymer via the placement of side-chains.
Tuning the electronic coupling in a low-bandgap donor-acceptor copolymer via the placement of side-chains.
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DOI：
10.1063/1.3562936
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发表时间：
2011-03
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影响因子：
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通讯作者：
Philipp M. Oberhumer;Ya-shih Huang;S. Massip;D. James;G. Tu;S. Albert-Seifried;D. Beljonne;J. Cornil;Ji‐Seon Kim;W. Huck;N. Greenham;J. Hodgkiss;R. Friend
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文献类型：
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作者：
Philipp M. Oberhumer;Ya-shih Huang;S. Massip;D. James;G. Tu;S. Albert-Seifried;D. Beljonne;J. Cornil;Ji‐Seon Kim;W. Huck;N. Greenham;J. Hodgkiss;R. Friend
我们提出了一种新的低带隙交替供体-受体共聚物聚[双-N，N-（4-辛基苯基）-双-N，N-苯基-1,4-苯二胺-5,5'-4',7‘，-二-2-噻吩基-2’，1',3'-苯并噻唑]（T8TBT）中己基侧链的存在和位置的影响的光谱和理论研究。我们使用电子吸收和拉曼光谱测量支持的计算链构象，电子跃迁，和拉曼模式。利用这些工具，我们发现立体要求的侧链构型会引起电子受体单元的扭曲，并减少与给体的电子相互作用。这导致蓝移和减弱（部分）电荷转移吸收带以及更高的光致发光效率。另一方面，空间松弛的侧链结构促进了施主和受体单元之间的耦合，并以牺牲发光效率为代价增强了吸收。通过改变侧链的位置来调整共轭聚合物的给体-受体特性的可能性对发光二极管、激光、显示器和光伏器件的优化具有非常重要的影响。
We present a spectroscopic and theoretical investigation of the effect of the presence and position of hexyl side-chains in the novel low-bandgap alternating donor-acceptor copolymer poly[bis-N,N-(4-octylphenyl)-bis-N,N-phenyl-1,4-phenylenediamine-alt-5,5'-4',7',-di-2-thienyl-2',1',3'-benzothiadiazole] (T8TBT). We use electronic absorption and Raman spectroscopic measurements supported by calculations of chain conformation, electronic transitions, and Raman modes. Using these tools, we find that sterically demanding side-chain configurations induce twisting in the electronic acceptor unit and reduce the electronic interaction with the donor. This leads to a blue-shifted and weakened (partial) charge-transfer absorption band together with a higher photoluminescence efficiency. On the other hand, sterically relaxed side-chain configurations promote coupling between donor and acceptor units and exhibit enhanced absorption at the expense of luminescence efficiency. The possibility of tuning the donor-acceptor character of conjugated polymers by varying the placement of side-chains has very important ramifications for light emitting diode, Laser, display, and photovoltaic device optimization.