Solvent quality-induced nucleation and growth of parallelepiped nanorods in dilute poly(3-hexylthiophene) (P3HT) solution and the impact on the crystalline morphology of solution-cast thin film
Solvent quality-induced nucleation and growth of parallelepiped nanorods in dilute poly(3-hexylthiophene) (P3HT) solution and the impact on the crystalline morphology of solution-cast thin film
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DOI：
10.1039/c2ce26666k
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发表时间：
2013-01-01
期刊：
影响因子：
3.1
通讯作者：
Hensley, Dale K.
中科院分区：
文献类型：
--
作者：
Keum, Jong K.;Xiao, Kai;Hensley, Dale K.
了解共轭聚合物在流延溶液中的链构象及其对溶液流延薄膜结晶形态的影响对于许多电子应用至关重要。使用小角中子散射，我们表明，良好溶解的聚（3-己基噻吩）（P3 HT）链在良好的溶剂（氯仿）形成长矩形平行六面体（RP）通过成核和生长过程后，增加不良溶剂（己烷）的体积分数超过一定的临界点。RP的生长是由于P3 HT主链沿RP长轴沿着发生p-p堆叠。将不同贫溶剂体积分数的P3 HT溶液滴注到Si晶片上制备薄膜，并利用二维掠入射X射线散射和一维X射线衍射对其进行了研究。结果表明，在溶液中生长的RP在溶剂蒸发后优先在基底上取向，其两个长轴平行于表面，与无序链相比，结晶度和晶体取向得到了很大改善。
Understanding the chain conformation of conjugated polymers in casting solutions and its impact on the crystalline morphology of solution-cast thin films is crucial for many electronic applications. Using small-angle neutron scattering, we show that well-dissolved poly(3-hexyl thiophene) (P3HT) chains in good solvent (chloroform) form long rectangular parallelepipeds (RPs) via nucleation and growth processes upon increasing the volume fraction of poor solvent (hexane) above a certain critical point. The growth of the RPs is due to the p-p stacking of the P3HT main backbone occurring along the long axis of the RPs. P3HT solutions prepared with different poor solvent volume fractions were drop-cast onto Si-wafers to prepare thin films, which were examined using 2D grazing-incidence X-ray scattering and 1D X-ray diffraction. The results indicate that the RPs grown in solution preferentially orient on the substrate with their two longer axes parallel to the surface after solvent evaporation, and give rise to much improved crystallinity and crystal orientation compared to the disordered chains.