Investigation On The Preparation Of C-Au-TiO₂ Compound Film And Its Photo Thermal Conversion Characteristics

Solar selective absorbing thin film is a kind of functional film which can realize the photo-thermal conversion of solar light.As the most critical part of the photo-thermal conversion,it provides a reliable solution for the efficient use of solar energy by humans.At present,solar energy selective absobing film can already achieve good solar absorption,but there are still some problems for its cost,stability and large-scale preparation technology.It is necessary to combine the characteristics of existing solar absorption films,consider their photo-thermal conversion performance and practical application to optimize design,reduce the cost of the film and improve the conversion performance of light and heat,which could promote its application in solar water heaters,solar thermal power plants,solar desalination and other fields.In this paper,on the basis of the research on the preparation of solar selective absorbing films and their photothermal conversion properties at home and abroad,the controlled preparation of C-Au-TiO₂ selective absorbing film was realized by sol-gel method.With numerical simulation and experimental method,the absorption and reflection characteristics of the film were analyzed.Simultaneously,the photo-thermal conversion experimental platform was established to explore the energy transport and conversion cha racteristics of the composite film.These main contents are as follows:The sol-gel method was used to prepare C-Au-TiO₂ selective absorbing thin films with suitable micro-nano structures.The mechanism of the formation of C-Au-TiO₂ thin film was analyzed during the reaction process.And the related factor affecting the morphology,structure and optical properties of the film were explored.Studies have shown that the prepared film has good selective absorption properties.The optical properties of the thin film structure were simulated using finite-difference time-domain method.And the influence of structure and composition of the thin film on the selective absorption performance was explored.The study shows that the composition and thickness of the film have a significant impact on its reflectivity.The photo-thermal conversion characteristics of the film was tested and some factors affecting the photo-thermal conversion efficiency were analyzed with the absorption spectrum of the film.The photo-thermal conversion characteristic of different micro-nano composite structure films was comprehensively compared.It can be found that the film has a good photo-thermal conversion ability under different angles of incident light.Finally,an experimental platform was set up to conduct solar water evaporation experiments to study the effect of different types of thin films and spectral absorption characteristics on evaporation performance.A numerical model for solar evaporation was established.Combin ing with the experimental result,the effect of different device parameters on the evaporation performance of solar water was studied.The research shows that the environmental humidity and the absorption rate of the film have a great influence on the evaporation effect,and the enhancement effect of the film on the evaporation area is limited by the area,showing the tendency of increasing first and then decreasing.