Preparation And Study Of CdS@CdSe Quantum Dots Sensitized Carbon Nanotubes Composite

Recently, due to the excellent electrical conductivity, large surface area, large aspect ratio and other characteristics, Carbon nanotubes (CNTs) was generally combined with Quantum dots (QDs) which had excellent photoelectric, to apply to the study of the solar cell light anode material. But there were too little active groups on the surface of the MWCNT to absorb large amounts of QDs, leading to the poor photovoltaic efficiency. So MWCNT grafted with PANI (MWCNT@PANI) were prepared to increase the number of active groups and then increased the absorption number of QDs to prepare high electrical conductivity, high photovoltaic efficiency material.Firstly, MWCNT grafted with PANI (MWCNT@PANI) were prepared by emulsion polymerization to increase the number of active groups on the surface of MWCNT. Due to the excellent intrinsic electrical conductivity of PANI and the P-π stacking interactions between PANI and MWCNT, the electronic could be transferred into MWCNT@PANI. Hence, the composite had excellent electrical conductivity, too. The structure of MWCNT@PANI composite was tested by FT-IR spectra, XRD patterns, EDS spectra, Raman spectra and HR-TEM. And the electric properties were tested by volume resistivity. All the results comprehensively showed that PANI had been successfully grafted on the surface of MWCNT and MWCNT@PANI composite had excellent electrical conductivity.Secondly,4-mercaptobenzoic acid was doped with the MWCNT@PANI to introduce QDs adsorptive-SH group. As a bridge,4-mercaptobenzoic acid connected MWCNT and QDs, which not only made it possible for MWCNT to combine with QDs, but also enhanced the electrical conductivity of composite. The structure and electric properties of MWCNT@PANI composite were tested by FT-IR spectra, EDS spectra and volume resistivity, respectively. The results showed that4-mercaptobenzoic acid had been successfully doped and MWCNT@PANI composite had more excellent electrical conductivity than MWCNT@PANI.Thirdly, CdS@CdSe QDs was prepared. And then we studied optical properties of QDs and the influence of QDs size on its emission wavelength. The EDS and HR-TEM testing results showed that CdS@CdSe QDs had been successfully prepared. Simultaneously, optical properties of QDs had been tested though Fluorescence spectra and fluorescence microscopy images, the results showed that emission wavelength of QDs exhibits a red-shift with the increasing diameter.Finally, we prepared MWCNT@PANI-SH@QDs composite successfully, and studied the effect of electrode film’s thicknesses and adsorption amount of QDs on cell efficiency when the composite was used as the solar photo-anode materials. The structure of MWCNT@PANI-SH@QDs composite was tested by EDS and HR-TEM, and the results showed that CdS@CdSe QDs was successfully absorbed on the surface of the MWCNT@PANI-SH. The optical properties of MWCNT@PANI-SH@QDs had been tested through Fluorescence spectra and UV-vis spectra, the results showed that MWCNT@PANI-SH@QDs could store light energy, and released it as an electric rather than a photon. Lastly, the solar photo-anode materials was tested under AM1.5illuminations, the power conversion efficiency could up to3.76%with the thickness of12±0.5μm and concentration of QDs for18±0.2%.