The impact of molecular weight, air exposure and molecular doping on the charge transport properties and electronic defects in dithienyl-diketopyrrolopyrrole-thieno[3,2-b]thiophene copolymers
The impact of molecular weight, air exposure and molecular doping on the charge transport properties and electronic defects in dithienyl-diketopyrrolopyrrole-thieno[3,2-b]thiophene copolymers
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DOI：
10.1039/c6tc03545k
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发表时间：
2016-11
影响因子：
6.4
通讯作者：
R. D. Pietro;Tim Erdmann;Naixiang Wang;Xuhai Liu;David Gräfe;Johannes Lenz;J. Brandt;Daniel Kasemann;K. Leo;M. Al-Hussein;K. Gerasimov;D. Doblas;D. Ivanov;B. Voit;D. Neher;A. Kiriy
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文献类型：
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作者：
R. D. Pietro;Tim Erdmann;Naixiang Wang;Xuhai Liu;David Gräfe;Johannes Lenz;J. Brandt;Daniel Kasemann;K. Leo;M. Al-Hussein;K. Gerasimov;D. Doblas;D. Ivanov;B. Voit;D. Neher;A. Kiriy
我们对通过Stille偶联缩聚反应合成的高分子量聚[3，6-（二噻吩-2-基）-2，5-二（2-辛基十二烷基）-吡咯并[3，4-c]吡咯-1，4-二酮-alt-噻吩并[3，2-B]噻吩] P（DPP 2 OD-TT）进行了深入研究，以了解分子量、加工条件与电荷传输之间的相关性。我们观察到随着分子量的增加，其在溶液中的聚集迅速增加，这强烈限制了重均分子量超过200 kg mol−1的溶解度和加工性。这导致聚合物的电荷传输性能受到严重限制。我们进一步观察到所有不同聚合物批次中都存在体电子缺陷，这些缺陷严重限制了电流，并在有机场效应晶体管中表现为迁移率的表观电荷密度依赖性。这些缺陷通过暴露于环境气氛而被钝化，如通过不再依赖于电荷密度的电流和迁移率的增加所证实的。使用2，2-（全氟萘-2，6-二亚基）二丙二腈（F6 TCNNQ）进行化学掺杂的结果进一步证实了这一点，这导致陷阱态的填充和高达1 cm 2 V−1 s−1的更高的电荷密度无关迁移率。
We performed an in-depth study of high molecular weight poly[3,6-(dithiophene-2-yl)-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thieno[3,2-b]thiophene] P(DPP2OD-TT) synthesized through the Stille coupling polycondensation in order to understand the correlation between molecular weight, processing conditions and charge transport. We observed a rapid increase in its aggregation in solution with increasing molecular weight which strongly limits the solubility and processability for weight average molecular weights beyond 200 kg mol−1. This results in severe limitation in the charge transport properties of the polymer. We further observe the presence of bulk electronic defects in all different polymer batches that severely limit the current flow and manifest themselves in organic field effect transistors as apparent charge density dependence of the mobility. These defects are passivated by exposure to an ambient atmosphere, as confirmed by an increase in current and mobility that is no more charge density dependent. This is further confirmed by the result of chemical doping using 2,2-(perfluoronaphthalene-2,6-diylidene)dimalononitrile, F6TCNNQ, which leads to the filling of the trap states and a higher charge density independent mobility of up to 1 cm2 V−1 s−1.