摘要 本篇主要在研究蒸鍍對位六聯苯分子在乾淨金表面以及不同自組裝單層分子膜表面，表面沉積的有機薄膜中的分子是否因為不同的表面性質而有不同的方向性。經由反射式紅外線光譜以及NEXAFS光譜，我們已經證明對位六聯苯分子蒸鍍在乾淨金表面時分子呈現平躺狀態，而在具有自組裝分子薄膜之表面上則呈現站立的型態。這兩種不同方向性的的薄膜在X-Ray繞射圖譜也可以清楚地加以解釋，並且在螢光光譜的強度上亦有極大的差異，在分子平躺的薄膜中螢光的強度是分子呈現站立的薄膜的數十至數百倍，這非常特別的現象與分子的方向性有絕對的關係。 若在刷磨處理過的聚亞甲基薄膜上作蒸鍍對位六聯苯實驗，由原子力顯微鏡的影像並輔以反射式紅外線光譜，確信分子受到配向膜的影響，因而晶體在表面上呈現特殊方向性的生長，推論對位六聯苯分子為與表面產生最小能量的狀態，而趨向平貼於表面且順著表面高分子鏈的方向。 此時我們已然可以在金表面利用SAM修飾、乾淨金表面以及刷磨處理的高分子薄膜，取得分子站立、平躺以及平面二維方向的有機半導體薄膜，對於未來應用於有機半導體元件具有潛在的應用價值。 Abstract The growth of p-hexaphenyl films by thermal evaporation on clean gold surface and self-assembled monolayer (SAM) modified gold surface was investigated by reflection absorption IR spectroscopy, NEXAFS technique and X-Ray diffraction. The results showed that p-hexaphenyl molecules oriented parallel to clean gold whereas they oriented perpendicular to SAM-modified Au surface, irrespective of the terminal functional group of the SAM involved. The film with flat-lying molecules and the film with perpendicular molecules exhibited very different fluorescence intensity, with flat-lying molecules showing 10~100 times higher intensity. Oriented thin films of p-hexaphenyl molecules were also prepared by vacuum deposition on rubbed polymethylene surfaces. Reflection absorption IR spectra showed that the p-hexaphenyl molecules were oriented parallel to the rubbed surface. AFM microscopy showed that crystals of p-hexaphenyl are aligning perpendicular to the rubbing direction. The alignment effect may come from interaction between oriented polymer chains and the molecules. Thus orientation control of organic semiconducting p-hexaphenyl in three dimensions can be achieved by various substrates. Use of these films in fabricating organic electronic devices will be explored further.
