Competition between Exceptionally Long-Range Alkyl Sidechain Ordering and Backbone Ordering in Semiconducting Polymers and Its Impact on Electronic and Optoelectronic Properties
Competition between Exceptionally Long-Range Alkyl Sidechain Ordering and Backbone Ordering in Semiconducting Polymers and Its Impact on Electronic and Optoelectronic Properties
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DOI：
10.1002/adfm.201806977
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发表时间：
2019-02-01
影响因子：
19
通讯作者：
Ade, Harald
中科院分区：
文献类型：
--
作者：
Carpenter, Joshua H.;Ghasemi, Masoud;Ade, Harald
分子内和分子间的有序性极大地影响了半导体聚合物的电子和光电性能。烷基侧链和共轭主链的排序之间的相互关系尚未完全详细，尽管有很多先前的努力。在这里，发现一个高度有序的烷基侧链相在六个代表性的半导体聚合物，确定从不同的光谱和衍射签名，报告。侧链排序表现出异常大的相干长度（>= 70 nm），诱导扭转/扭曲主链无序，并导致具有与无序主链层交替的有序侧链层的垂直多层纳米结构。聚{4-（5-（4，8-双（3-丁基壬基）-6-甲基苯并[1，2-B：4，5-B ']二噻吩-2-基）噻吩-2-基）-2-（2-丁基辛基）-5，6-二氟-7-（5-甲基噻吩-2-基）-2H-苯并[d][1，2，3]三唑}（PBnDT-FTAZ）在模型体系中的量热法和原位变温散射测量清楚地描述了这种有序竞争，这种竞争阻止了两个部分同时进行长程有序。长程侧链有序可以被利用作为一个瞬态制造PBnDT-FTAZ膜具有非典型的边缘上的纹理和2.5倍提高的场效应晶体管迁移率。所观察到的部分之间的排序的影响意味着，改进的分子设计可以产生协同作用，而不是破坏性的排序效果。考虑到观察到的大的侧链相干长度，这种协同有序应该极大地改善主链有序的相干长度，从而改善电子和光电性质，例如电荷传输和激子扩散长度。
Intra- and intermolecular ordering greatly impacts the electronic and optoelectronic properties of semiconducting polymers. The interrelationship between ordering of alkyl sidechains and conjugated backbones has yet to be fully detailed, despite much prior effort. Here, the discovery of a highly ordered alkyl sidechain phase in six representative semiconducting polymers, determined from distinct spectroscopic and diffraction signatures, is reported. The sidechain ordering exhibits unusually large coherence lengths (>= 70 nm), induces torsional/twisting backbone disorder, and results in a vertically multilayered nanostructure with ordered sidechain layers alternating with disordered backbone layers. Calorimetry and in situ variable temperature scattering measurements in a model system poly{4-(5-(4,8-bis(3-butylnonyl)-6-methylbenzo[1,2-b:4,5-b ']dithiophen-2-yl)thiophen-2-yl)-2-(2-butyloctyl)-5,6-difluoro-7-(5-methylthiophen-2-yl)-2H-benzo[d][1,2,3]triazole} (PBnDT-FTAZ) clearly delineate this competition of ordering that prevents simultaneous long-range order of both moieties. The long-range sidechain ordering can be exploited as a transient state to fabricate PBnDT-FTAZ films with an atypical edge-on texture and 2.5x improved field-effect transistor mobility. The observed influence of ordering between the moieties implies that improved molecular design can produce synergistic rather than destructive ordering effects. Given the large sidechain coherence lengths observed, such synergistic ordering should greatly improve the coherence length of backbone ordering and thereby improve electronic and optoelectronic properties such as charge transport and exciton diffusion lengths.