Photoemission studies of polythiophene and polyphenyl films produced via surface polymerization by ion-assisted deposition
Photoemission studies of polythiophene and polyphenyl films produced via surface polymerization by ion-assisted deposition
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DOI：
10.1021/jp0451445
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发表时间：
2005-04-21
影响因子：
3.3
通讯作者：
Hanley, L
中科院分区：
文献类型：
--
作者：
Tepavcevic, S;Wroble, AT;Hanley, L
导电聚合物薄膜是通过大量选择的高温噻吩离子与α -噻吩（3T）或对噻吩（3P）中性有机单体的热束同时在表面上生长的。质谱和x射线光电子能谱先前证实了200 eV C4H4S+在离子辅助沉积（SPIAD）表面聚合过程中对3T和3P的聚合。利用紫外光电子能谱（UPS）和偏振近边x射线吸收精细结构能谱（NEXAFS）对这些薄膜的电子结构进行了探测，并与蒸发薄膜的类似光谱进行了比较。根据UPS和NEXAFS测量的已占据和未占据的价带状态，spad形成的导电聚合物薄膜显示出新的价带特征，这是由于它们的带隙和空穴注入势阻挡都减少了。这些薄膜电子结构的变化是由于spad引起的电子共轭长度的增加和其他薄膜结构的变化。
Conducting polymer films are grown by mass-selected, hyperthermal thiophene ions coincident on a surface with a thermal beam of organic monomers of either alpha-terthiophene (3T) or p-terphenyl (3P) neutrals. Mass spectrometry and X-ray photoelectron spectroscopy previously verified polymerization of both 3T and 3P by 200 eV C4H4S+ during surface polymerization by ion-assisted deposition (SPIAD). The electronic structure of these films are probed here by ultraviolet photoelectron spectroscopy (UPS) and polarized near-edge X-ray absorption fine structure spectroscopy (NEXAFS) and compared with similar spectra of evaporated films. The conducting polymer films formed by SPIAD display new valence band features resulting from a reduction in both their band gap and barrier to hole injection, which are calculated from the occupied and unoccupied valence band states measured by UPS and NEXAFS. These changes in film electronic structure result from an increase in the electron conjugation length and other changes in film structure induced by SPIAD.