| Summary: | 碩士 === 東海大學 === 電機工程學系 === 101 === In this study, the laboratory-made flexible multi walled carbon nanotube paper, so called buckypaper (BP) with its excellent electrical and optical properties of carbon nanotubes in the network structure from the micro to macro scale, and then by changing it in the form under the solar light illumination, to further enhance the MWCNTs buckypaper for good optoelectronics applications.
The experimental measurement is divided into two parts; the first part is done for the fabrication of buckypaper and its basic electrical measurements, includes finding the best illumination area, the optimal illumination mode and Red-Green-Blue (RGB) best absorption measurements. The second part is modification part, in this experiment copper oxide powder and zinc oxide powder was used for doping into the buckypaper. Zinc oxide powder was purchased and the copper oxide particles are produced using a thermal evaporation method. Annealing the copper oxide was performed in the argon and oxygen atmosphere with the ratio of 3 to 0.9 and maintains pressure of 300mtorr. Then the sample was characterized by X-ray diffraction (XRD) for calculating particle size and also for structural identification. At CuO and ZnO the doping process was followed for the weight percentage of 10% to 50%. The sample was placed under the solar-light simulator, then illuminated in full and then gradient illumination to observe the photo-current and photo-voltage characteristics. It was found that the gradient illumination pattern and doping powders have enhanced the BP’s optical response. In order to compare, the BP sample with some dimension was connected in series and parallel, and finally involving plasma modification, so the modified sample were studied for carrier concentration differences which arises from varying plasma power. The effect was observed by illuminating the sample under solar light gradient, which results in increasing the carrier concentration and observing increase in the photo-voltage and photo-current.
The results showed that in this experiment, the photo-gradient for testing the buckypaper was optimum with the sample area 1.6 cm x 0.4 cm, an area of 0.64 cm2. The observed best mode of illumination is found to be the wavelength of red light. Compared to the undoped BP the 20% doped copper oxide (6.5nm) powder shows 18.5 times enhancement of photocurrent and 6 times photo-voltage and under the gradient illumination mode, the photocurrent and photovoltage further improved 4.6 and 4.92 times respectively. This study successfully process the undoped buckypaper and doping and changes in illumination mode and connecting the BP in series and parallel, etc. can enhance the optical properties. So it can conclude that the multi walled CNT buckypaper (BP) can be more advantageous to the application in solar cell research.
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