| Summary: | 碩士 === 國立臺灣科技大學 === 化學工程系 === 101 === There are many kinds of methods to fabricate quantum dots sensitized solar cells (QDSSCs). In this study, microwave reactor was employed to synthesize cadmium selenide (CdSe) quantum dots directly on the surfaces of titanium dioxide nanoparticles (TiO2-NPs) photoanode for the study of solar cells. In the microwave method, the photoanode can immerse into the precursor solution directly and control the decoration of quantum dots by immersion time. Due to provide the necessary energy immediately by microwave irradiation, quantum sots can decorate on the surfaces of photoanode rapidly and avoid the agglomeration of quantum dots on top of photoanodes.
In this work, TiO2-NPs were used as photoanodes due to their high specific surface areas. Firstly, we discuss the influence of reaction time on the performance of QDSSCs. From results, we can find the conversion efficiency of QDSSCs can arrive 1.02 % when the precursor solution was refreshed twice and each time was 5 min. In addition, the conversion efficiency can arrive 1.68 % when different layers of cadmium sulfide and zinc sulfide were decorated on the surfaces of photoanodes. The carrier transport properties of these types of QDSSCs can be resolved by using electrochemical impedance spectroscopy technique with suitable equivalent circuit model.
As for the counter electrode, we also prepared Co3S4 electrodes to replace Pt electrodes in our QDSSCs. The performance of Co3S4 electrodes can be evaluated by measuring charge transport resistance. From measurement, we can find the charge transfer resistance of Co3S4 has improved around 20 times compared with Pt counter electrode. The efficiency of QDSSCs can arrive 2.72 %.Furthermore,we also add TiO2-MS scattering layer on photoandoes. The efficiency of QDSSCs can arrive 2.92%
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