| Summary: | 碩士 === 國立中正大學 === 化學暨生物化學研究所 === 100 === Inverse opal photonic crystal is a multi-hole periodic structure, formed by using different dielectric materials to prepare photonic crystals with different properties. In our study, a photonic crystal with photonic bandgap matching the absorption band of a photosensitizer is designed in order that the reflection of specific wavelength range of light by the photonic crystal structure can improve the photoelectric conversion efficiency of dye-sensitized solar cells.
First, we used P25-TiO2 particles to prepare TiO2 film, then used the evaporation method to make a polystyrene (PS) opal photonic crystal as a template on the surface of the TiO2 thin film, and then further used dip-coating method to fill TiO2 precursor in the template. Afterward, the product was calcined to remove the template, and a composite structure of TiO2 inverse opal photonic crystal on TiO2 film was obtained. This structure was used as a photoelectrode of dye-sensitized solar cells. The photonic crystals we prepared have the photonic bandgap located at about 430nm in air. When the photonic crystal was placed in dye-sensitized solar cells, the photonic bandgap shifted to 550nm due to change of effective refractive index of the photonic crystal when the electrolyte fills its porous structure. As a result, the photonic bandgap matches with the absorption band of the photosensitizer N-719 at about 535nm.
Utilizing the characteristics of photonic crystal, we have successfully prepared an improved photoelectrode with a photonic crystal on TiO2 film, where the photonic bandgap matched the absorption band of the photosensitizer. The photoelectric conversion efficiency of the photoelectrode improves as compared to that of the photoelectrode with only TiO2 film of the same thickness.
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