Tepavcevic Sanja, Wroble Amanda T, Bissen Mark, Wallace Daniel J, Choi Yongsoo, Hanley Luke
Department of Chemistry (m/c 111), University of Illinois at Chicago, Chicago, Illinois 60607-7061, USA.
J Phys Chem B. 2005 Apr 21;109(15):7134-40. doi: 10.1021/jp0451445.
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 C(4)H(4)S(+) 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.
通过质量选择的超热噻吩离子与α-三联噻吩（3T）或对三联苯（3P）中性有机单体的热束同时作用于表面，生长导电聚合物薄膜。质谱和X射线光电子能谱先前已证实，在离子辅助沉积（SPIAD）表面聚合过程中，200 eV C(4)H(4)S(+)可使3T和3P发生聚合。本文通过紫外光电子能谱（UPS）和偏振近边X射线吸收精细结构光谱（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。由SPIAD形成的导电聚合物薄膜显示出新的价带特征，这是由于其带隙和空穴注入势垒的降低所致，这些是根据UPS和NEXAFS测量的占据和未占据价带态计算得出的。薄膜电子结构的这些变化是由SPIAD引起的电子共轭长度增加和薄膜结构的其他变化导致的。
