Construction Of Ultrathin Films Of Organic Semiconductors By Langmuir-Blodgett Technique

In this thesis, several techniques for constructing ultrathin organic films were reviewed. By employing Langmuir-Blodgett (LB) method, thin films of several organic semiconductors were fabricated. The micro-structure of the thin films were characerized and the effects of several experimental factors were evaluated. By combining microcontact printing (μCP) and self-assembly techniques, the micro-patterns of antibody protein were fabricated. The surface reactions along with the pattern formation process were monitored by imaging ellipsometry. The thesis includes the following three parts1 Thin film morphology of cruciform organic non-amphiphilic semiconductor prepared by Langmuir-Blodget methodConventional Langmuir-Blodgett (LB) technique generally requires the organic molecules to be amphiphilic. We report herein the LB fabrication of the unltrthin films of three new cruciform non-amphiphilic organic semiconductors. The effects of the various experimental parameters on the film morphology of these LB films were investigated, such as surface pressure and deposition cycles. By controlling the deposition conditions, we can effectively control the molecular packing at water/air interface and consequeciently tailor the nanocrystals structure. The film morphologies were investigated by atomic force miscoscopy (AFM) and scanning electron micrscopy (SEM). And the optical properties of the thin films were charactered by UV-Vis and photolumninance (PL) spectroscopy. It was found that the molecular density at the air/water interface playing the dominate role on the morphologies of LB films. This study provides new understanding of surface aggregate formation of various non-amphiphilic organic moleculers self-assembled at the air-water interface, which can be used as potentially new strategies of controlled film's nanostructure for organic electronic applications. 2 Thin film formation of a linear OPV molecule by Langmuir-Blodget methodThe thin films of a new linear non-amphiphilic OPV molecule were fabricated by LB method. The effects of different factors on the film structure and spectroscopic properties were investigated by SEM, UV-Vis and PL method. By controlling the surface pressure and deposition cycles different film morphologies were obtained. Regular nanorods were obtained on the LB films which are in higher quality than that obtained by drop casting method.3 Patterning antibody into highly ordered array and their characterization using imaging ellipsometryHighly ordered antibody array patterns were prepared by combining microcontact printing and self-assembly techniques. The thichness changes occurred during the patterning formation process were mornitored by imaging ellipsometry. Imaging ellipsometry is a powerful technique to generate two-dimensional maps of the protein arrays and gives 3D-profile of the microarrays, which provides a cheap, fast and marker-free detection method for studying the model bio-chip systems. An accurate measurement of the optical properties of the reaction layer and a quick and high resolution inspection to sample surface properties were achieved.