Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands.
ACS Appl Mater Interfaces. 2013 May 22;5(10):4417-22. doi: 10.1021/am400786c. Epub 2013 May 10.
We investigated the role of metal/organic semiconductor interface morphology on the charge transport mechanisms and energy level alignment of the n-channel semiconductor poly{[N,N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)} (P(NDI2ODT2)). Variable-temperature study of well-ordered edge-on-oriented P(NDI2OD-T2) monolayer and multilayer field-effect transistors fabricated via Langmuir-Schäfer (LS) method reveals a higher activation energy for the edge-on morphology when compared to that extracted for the face-on oriented P(NDI2OD-T2) spin-coated films, which showed a weaker temperature dependence. Near-ultraviolet inverse photoemission and low-energy electron transmission spectroscopies are utilized to study these microstructurally defined polymeric films. The cross correlations of these techniques with the device characterization reveals the role of the molecular orientation at the semiconductor/contact interface in shifting the charge injection barrier. Finally, we demonstrate that the injection barrier for electrons is higher for the LS/edge-on than in the spin-coated/face-on films.
我们研究了金属/有机半导体界面形态对 n 通道半导体聚{[N,N'-双(2-辛基十二烷基)-萘-1,4,5,8-双(二羧酸二酰亚胺)-2,6-二基]-交替-5,5'-(2,2'-联噻吩)}（P（NDI2ODT2））的电荷输运机制和能级排列的作用。通过 Langmuir-Schäfer（LS）方法制备的有序边缘取向 P（NDI2OD-T2）单层和多层场效应晶体管的变温研究表明，与旋涂薄膜相比，边缘取向形态的活化能更高，而旋涂薄膜的温度依赖性较弱。近紫外光反向光发射和低能电子传输光谱学用于研究这些微结构定义的聚合物薄膜。这些技术与器件特性的交叉相关表明了半导体/接触界面处分子取向在改变电荷注入势垒方面的作用。最后，我们证明 LS/边缘取向的电子注入势垒高于旋涂/面取向的薄膜。
