RESUMEN
Powder aerosol deposition (PAD) is a unique ceramic spray coating method that produces dense and well-adhering thick-films directly at room temperature, without requiring any heating or sintering. After the successful film formation, mechanical film properties like hardness or plasma resistance are remarkably good. However, when it comes to electrical properties like permittivity or electrical conductivity, the nanocrystalline structure of PAD films combined with high internal strains deteriorates partly the characteristic properties. The electrical conductivity may already be present within the as-deposited films. However, it is mostly lowered by several orders of magnitude. Therefore, a thermal post-deposition annealing is oftentimes required. In this work, electrically conducting films produced by powder aerosol deposition are surveyed based on published data. Their microstructural and electrical behavior during the post-deposition annealing treatment is summarized and reasons for the lowered electrical conductivity are identified. Additionally, the processes taking place during annealing, which eventually allow to regain bulk-like functional properties, are examined. A universal annealing behavior is found that leads to a quantitative recommendation for the suitable film annealing temperatures to regain the electrical conductivities.
RESUMEN
The Aerosol Deposition (AD) method has the unique property to allow for manufacturing dense ceramic films at room temperature. As found in many publications, the deposition process is very sensitive to powder properties. In particular, powders of nano-sized particles and grains, e.g., from precipitation, are usually beyond the conventional size range of AD processability, yielding chalk-like films of low mechanical stability. Thus, the conventional AD process is limited in applicability. In this study, we try to overcome this problem by adapting the standard milling treatment of powders for improved deposition by additional temperature pre-treatment. Using commercial tin dioxide and including a temperature treatment for grain growth, makes the powder accessible to deposition. In this way, we achieve optically translucent and conductive SnO2 thick films. With the application such as a gas sensitive film as one of many possible applications for SnO2 thick-films, the sensors show excellent response to various reducing gases. This study shows one exemplary way of extending the range of adequate powder and applications for the AD method.
RESUMEN
Owing to its ability to produce dense thick-films at room temperature directly from a ceramic powder, the Aerosol Deposition Method (AD) possesses a unique feature in ceramics processing. For this technology, the aerosol generation of particles is a decisive part of reliable process control. However, there has only been a small amount of work published addressing this topic. In this work, we compare the aerosolization and deposition behavior of a fluidized bed generator with an aerosol generator with the rotary brush principle. While film properties very much depend on deposition time for the fluidized bed generator, films produced with the brush generator show a constant film profile, and their film thickness correlates with the controllable aerosol concentration and the duration of deposition. This type of aerosol generation may improve the setup towards a more reliable AD process.
RESUMEN
We present the successful fabrication of CH3NH3PbI3 perovskite layers by the aerosol deposition method (ADM). The layers show high structural purity and compactness, thus making them suitable for application in perovskite-based optoelectronic devices. By using the aerosol deposition method we are able to decouple material synthesis from layer processing. Our results therefore allow for enhanced and easy control over the fabrication of perovskite-based devices, further paving the way for their commercialization.