Colloidal carbon and silica : their use in solar energy

Abstract

The aims of this thesis are to optimise the use of colloidal carbon and silica in photothermal solar selective surface coatings and colloidal silica in antireflection coatings. (i) Photothermal solar selective coatings. Using an effective medium theory (Maxwell Garnett equation) and the experimental determination of the conversion efficiency, the optimum volume fraction and film thickness of the colloidal carbon and silica coatings can be determined. The temperature stability of these coatings will also be discussed. (ii) Antireflection coatings. In studying the effect of the antireflection properties of the colloidal silica coatings with respect to the variation of the silica primary particle size, a determination of the optimum colloidal silica coating can be made. Chemical bath dipping procedures will be used in this thesis as a means of applying the coatings. This is seen as an economically attractive method in fabricating these films.