| Summary: | 碩士 === 國立中興大學 === 化學工程學系所 === 101 === Solar cell applications are mainly in the outdoors, in order to facilitate the use of light energy into electrical energy. There are many advantages in organic solar cell , such as by changing the properties of organic material or methods of manufacturing the process, so that the photoelectric conversion efficiency will increase.
By modified organic material, the light absorption wavelength range of organic material can increase, indirectly enhance the amount of light absorption. The other hand, it also can improve the solubility of the organic material. Good solubility will reduce the problem in films manufacturing
This study was conducted using a different solvent: methylene chloride, toluene and cyclohexanone, respectively mixed solvent of ethyl acetate. Dissolved organic material in a solvent：copper phthalocyanine darivative(CuPc-C7)、perylene derivative(perylene-C7), a film was formed with the method of spin coating. Detecting the absorption of film by the UV-Vis, and by calculating, we can obtain the absorption of the unit thickness. Experimental results show that the films made of different solvents, the absorption coefficient is different. The reasons mainly result from the film surface morphology. The atomic force microscope was used to observe the surface morphology of the films. For example, the CuPc-C7 film made from cyclohexanone solvent is a uniform, dense surface morphology, and it’s roughness is 0.81nm. The film prepared from dichloromethane is worse than made of cyclohexanone, and it’s roughness is 1.46nm. The surface morphology of film made from toluene is the most rough, and it’s roughness is 2.71nm. Because cyclohexanone is aprotic polarity solvent (ε:13.3~25.0), it contributes to arranging molecules. In low temperature baking process, forming the film is slow, it helps molecular spontaneous arrangement. Because of the low boiling point of methylene chloride, 40°C, the films made of methylene chloride is also good. And uniform, dense surface morphology will help to form heterojunction, thus will increase the photoelectric conversion efficiency of the solar cell.
Finally, we study on the mixed materials of donor and acceptor by Taguchi method, and will obtain the factor of effecting the photoelectric conversion efficiency of the solar cell. By Taguchi method, the film processing will be improved. Under optimal condition (Using a mixed solvent of cyclohexanone, DA ratio of 2:1, 5% concentration, baking conditions 90 ° C 20 minutes), the RMS roughness is 1.88(nm), and the absorption coefficient is 0.63(au/μm). The results also confirm that, in the optimum conditions, the absorption coefficient increase 0.4(au/μm),and with expected results.
|
|---|
