| Organic semiconductor films have enormous potential applications in a lot of aspects because of the light weight, mechanical flexibility, roll-to-roll large-scale processing, and molecular design. Organic semiconductor films get enough attentions in the applications of organic solar-cells because it is a competitor of the silicon-based solar cells. More and more researchers have dedicated themselves to searching and synthesizing organic materials and improving the conversion efficiency of the solar cells. However, organic solar-cells will suffer from the challenge of combining efficiency, stability and large-scale processing in the future. For conversion efficiency problem, this is an obvious and easy to attract attention, but the physical and chemical stability of the organic semiconductor from another aspect also affects the conversion efficiency, and even directly form the restriction of its industrial application. Especially, long-time light has very important influence on the movemention of the polymer molecular chain or the change of the chemical valence bond, this instability can be directly reflected in such as physical morphology of organic semiconductor film interface, and the transformation of the chemical composition, and physical and chemical changes. The most typical example of physical change is micro phase separation of polymer blend which cause component distribution changes in the space of the film, namely, the nonuniformity of the micro and macro. Chemical change will directilly lead to the change of surface energy. At present, people research on chemical stability by energy spectrum, spectral spectrum and building2D/3D image, for the physical change, the spatial distribution of the microfacies and interface inhomogeneity depend on the atomic force probe, electronic microscope. Happily, the wettability of the surface, a method can reflect physical change as well as correlation surface energy change, is worth exploring as a kind of effective method to study the stability and uniformity of the organic film. This thesis is based on the idea, the organic film on the basal physical nonuniformity problem through the liquid-solid contact angle change to characterizate; the dependencies of molecular deposition film chain spatial morphology and the solid-liquid interface curvature to evaluate. Moreover, the wettability of the organic materials has attracted much attention due to their potential applications in anti-corrosion, antistatic coating, conductive fabric and biology. Especially, the wettability of surface can be tuned by using the method of photoelectric coupling. The content of this thesis mainly focuses on the stability and surface wettability of organic semiconductor thin films. The main content of this paper are presented as follows:(1)Firstly, the relationship between the solubility of PCBM and P3HT in organic solvent and the solvent evaporation rate was investigated. Due to the solvent evaporation rate is directly related to organic film uniformity in the process of formation, the internal flow was the important influencing factors for organic film uniformity. The effects of several kinds of organic solvent on PCBM solubility were investigated experimentally, including toluene, chloroform and o-dichlorobenzene. The results indicated that the PCBM in o-dichlorobenzene have good solubility.(2) Secondly, the effects of the droplet sizes and solute concentrationes of poly3hexylthiophene (P3HT) and fullerene derivative (PCBM) on the droplet internal flow, molecular chain, the spatial distribution and the droplet morphology instability during drying process of polymer solution droplets deposited on the substrate. The results showed that the width of coffee rings deposited from the evaporation of P3HT solution increased with the improvement of the concentration of polymer solutions and the size of droplet has little effect on the pattern. The pattern deposited by the PCBM solution presented irregular phenomenon varying with the concentration and the size of the droplets.(3)The influence of the different time of UV light on wettability of the ITO/P3HT:PCBM blend was studied by contact angle measurement. AFM and XPS were used to analyze the change of wettability. The results indicated that the wettability had not changed because the roughness and chemical composition of the surface has remained the same.(4)The influence of the different time of UV light on wettability of the ITO/ZnO/P3HT film was studied by contact angle measurement. The ITO/ZnO/P3HT thin film was prepared by hydrothermal method and spin coating method. AFM and XPS were used to analyze the change of wettability. The results indicated that the wettability of the surface had changed from hydrophobic (CA=111°)to hydrophilic (CA=31°) as the illumination time changed from1h to7h.
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