A plasmonic effect of silver nanoparticles (Ag NPs) in dye-sensitized solar cells (DSSCs) is studied. The solutions of silver nitrate in isopropanol, ethylene glycol, or in TiO2 sol were examined as possible precursors for Ag NPs formation. The solutions were dip-coated on the top of the porous TiO2 layer. The results of optical measurements confirmed the formation of Ag NPs throughout the porous TiO2 layer after the heat treatment of the layers above 100∘C. Heat treatment at 220∘C was found to be optimal regarding the formation of the Ag NPs.The porous TiO2 layers with Ag NPs have been evaluated also in DSSC by measuring current-voltage characteristics and the external quantum efficiency of the cells. In addition, the amount of adsorbed dye has been determined to prove the plasmonic effect in the cells. The I-V characterization of the DSSCs revealed an increase of the short circuit current in the presence of Ag NPs although the amount of the attached dye molecules decreased. These results confirm that the performance enhancement is related to the plasmonic effect. However, neither a thin sol-gel TiO2 layer nor poly(4-vinylpyridine) shells provide effective protection for the long term stability of the Ag NPs against the corrosion of I3−/I− based electrolyte.
COBISS.SI-ID: 10430804
In this paper previously developed combined model of non-conformal layer growth is used to calculate positions in thin-film silicon solar cells where defective regions are expected to be formed within semiconductor layers, depending on the substrate texture. This enables omission of the textures leading to cells of poor electrical quality in the early process of optical optimisation of the cells and substrate texture design. Coupled with three-dimensional rigorous optical simulations, substrate textures are optimised with respect to high short-circuit current and defectless layer growth in micromorph silicon solar cells. Firstly, the approach of determination of defective regions is validated on realistic structures. Secondly, analysis of the effects of texture shape and of the material and the thickness of the grown layer is carried out. Thirdly, optimisation of substrate texture for micromorph type of solar cell is performed for sinusoidal, widened and semi-circular textures. Results on widened textures show, that smoothing/widening of the valleys does not always suppress the formation of defective regions in μc-Si:H and a-Si:H layers. A semi-circular type of the texture is determined to be the most appropriate for defectless absorbers in the analysed micromorph solar cells in substrate configuration, resulting also in up to 85% increase in short-circuit current density of the bottom cell.
COBISS.SI-ID: 10867540