Mono/bidentate thiol oligoarylene-based self-assembled monolayers (SAMs) for interface engineering
作者:Stefano Casalini、Francesca Leonardi、Carlo A. Bortolotti、Alessandra Operamolla、Omar Hassan Omar、Licia Paltrinieri、Cristiano Albonetti、Gianluca M. Farinola、Fabio Biscarini
DOI:10.1039/c2jm30838j
日期:——
A new set of linear oligoarylene thiol molecules, namely (4′-(Thiophen-2-yl)Biphenyl-3,5-diyl)Dimethanethiol (TBD), (4′-(Thiophen-2-yl)Biphenyl-4-yl)Methanethiol (TBM) and ([1,1′;4′,1′′]Terphenyl-3,5-diyl)Dimethanethiol (TD), were synthesized and used for functionalizing the polycrystalline gold electrodes. Such molecules differ for the number of anchoring groups (TBM vs. TBD) and the terminal rings (TD vs. TBD). As shown by electrochemical measurements, they form homogeneous and pinholes-free self-assembly monolayers (SAMs) when deposited on the gold electrode. Moreover, the wettability of the functionalized surface and the morphological changes of pentacene films grown on SAMs were investigated by contact angle and atomic force microscopy, respectively. OTFT has been used as organic gauge for investigating the metal–SAM–organic semiconductor structure. Charge carriers mobility, threshold voltage, contact resistance were measured in both air and vacuum to assess the influence of the anchoring groups and the terminal rings to the transistor performance. Although these SAMs do not show an improvement of mobility due to an increase of contact resistance, they allow a better modulation of the current flowing across the electrode–organic semiconductor (OS) interface, pointing out the structural differences between the three SAMs in terms of resistance drop combined with the critical voltage.
合成了一组新的线性硫醇寡聚芳烃分子,即(4′-(噻吩-2-基)联苯-3,5-二基)二甲硫醇(TBD)、(4′-(噻吩-2-基)联苯-4-基)甲硫醇(TBM)和([1,1′;4′,1′′]三联苯-3,5-二基)二甲硫醇(TD),并用于功能化多晶金电极。这些分子因锚定基团的数量(TBM vs. TBD)和末端环(TD vs. TBD)而有所不同。电化学测量结果表明,当沉积在金电极上时,它们形成了均匀且无针孔的自组装单层(SAMs)。此外,通过接触角和原子力显微镜分别研究了功能化表面的润湿性和在SAMs上生长的并五苯薄膜的形态变化。有机薄膜晶体管(OTFT)已被用作研究金属-SAM-有机半导体结构的测量工具。在空气和真空环境中测量载流子迁移率、阈值电压和接触电阻,以评估锚定基团和末端环对晶体管性能的影响。尽管这些SAMs因接触电阻的增加而没有提高迁移率,但它们能够更好地调节流经电极-有机半导体(OS)界面的电流,指出了三个SAMs在抵抗电压降低与临界电压方面的结构差异。