Structure Evolution of Poly(3-hexylthiophene) on Si Wafer and Poly(vinylphenol) Sublayer
Structure Evolution of Poly(3-hexylthiophene) on Si Wafer and Poly(vinylphenol) Sublayer
复制标题
硅片和聚(乙烯基苯酚)底层上聚(3-己基噻吩)的结构演化
DOI：
10.1021/la501542h
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发表时间：
2014-07-01
期刊：
影响因子：
3.9
通讯作者：
Yan, Shouke
中科院分区：
文献类型：
--
作者：
Sun, Xiaoli;Ren, Zhongjie;Yan, Shouke
利用X射线分析技术详细研究了Si片上P3 HT薄膜和PVPh覆盖的Si片在加热、热退火和熔融再结晶过程中的结构演变。研究了衬底对P3 HT薄膜晶化行为和界面结构的影响。对于沉积在Si衬底上的P3 HT薄膜，发现P3 HT晶体的稳定性与取向有关。与b轴垂直于衬底的晶体取向，即，正面分子取向，比与a轴垂直于衬底排列的晶体（侧面分子取向）更不稳定。热退火温度对P3 HT的分子结构，包括晶体结构、膜厚度和表面粗糙度起着重要作用。在较高温度下退火后，在冷却过程中伴随着a轴的收缩形成新的晶体。熔体再结晶有利于形成更稳定的P3 HT晶体，分子取向为侧向。PVPh基体对溶液浇铸P3 HT的结晶行为没有显著影响，但抑制了P3 HT晶体的形成，晶体具有面对分子取向。然而，P3 HT和PVPh的界面形态通过在升高的温度下退火而改变。在160 ℃左右，P3 HT/PVPh界面由锐界变为弥散界。PVPh亚层在一定程度上抑制了P3 HT的熔融再结晶，导致a轴轻微膨胀。
The structure evolution of P3HT thin films on Si wafer and PVPh covered Si wafer during heating, thermal annealing, and melt recrystallization processes has been studied in detail using X-ray analysis techniques. The effect of substrate on the crystallization behavior and interface structure of P3HT films was explored. For the P3HT films deposited on the Si substrate, it was found that the stability of P3HT crystals is orientation dependent. The crystals oriented with b-axis normal to the substrate, that is, a face-on molecular orientation, are less stable than those with the a-axis arranged normal to the substrate (side-on molecular orientation). Thermal annealing temperature plays an important role in the molecular structure of P3HT including crystal structure, film thickness, and surface roughness. After annealing at relatively high temperature, new crystals form during the cooling process accompanied by the shrinking of a-axis. Moreover, the melt recrystallization favors the formation of more stable P3HT crystals with side-on molecular orientation. The PVPh substrate does not affect the crystallization behavior of solution cast P3HT significantly but inhibits the formation of P3HT crystal with face-on molecular orientation. However, the interfacial morphology of P3HT and PVPh changes by annealing at elevated temperature. The P3HT/PVPh interface changes from a sharply defined one into a diffused one at around 160 degrees C. The PVPh sublayer inhibits the melt recrystallization of P3HT to some extent, leading to a slight expansion of the a-axis.