| Summary: | 碩士 === 國立中正大學 === 機械工程學系暨研究所 === 100 === Based on the spin coating method, this study aims to enhance the performance of an organic solar cell through modifying properties of anode and hole transport layer using metallic nanoparticles. The oxidized silver nanoparticles, (AgOx-NPs) are used to modify the property of the ITO (indium tin oxide) anode and the gold nanoparticles (Au-NPs) are employed to amend the characteristics of the PEDOT:PSS hole transport layer.
The silver nitrate solution was first spin-coated on the top of an ITO glass slide. The silver nanoparticles, Ag-NPs, were generated by thermal reduction. The amount and size of the resulting Ag-NPs are dependent on the concentration of the silver nitrate solution and the thermal reduction time. The resulting ITO/AgOx-NPs substrate was then obtained by exposing the ITO/Ag-NPs substrate to the ultraviolet-ozone irradiation that oxidized the Ag-NPs into AgOx-NPs. Since the work function of AgOx is between the PEDOT:PSS hole transport layer and the ITO anode, a better in-between ohmic contact was expected that resulted in reducing the energy barrier and boosting transport of holes. Compared with the AgOx NPs in the literature, where a silver thin film was first deposited using thermal evaporation, the present approach takes the advantage that the AgOx is presented in the nanoparticles that insignificantly affect light penetration and absorption. Results show a solar cell device with the enhancement of the overall energy conservation efficiency up to 22% was achievable.
The employed Au-NPs for modifying the PEDOT:PSS hole transport layer were negatively surface charged and with diameters around 23 nm. The surface electrostatic repulsion helped the NPs dispersing uniformly in the PEDOT:PSS/Au-NPs solution and the resulting thin film as well. The photoluminance (PL) measurement indicated, with the existence of the Au-NPs, an about 38% enhancement in PL intensity within the wavelength range of 600 – 700 nm was obtainable and the resulting device PCE (photoelectric conversion efficiency) was 36% enhancement, from 2.47% without Au-NPs to 3.37% with Au-NPs.
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