Abstract: The invention provides a close space annealing method and a method for preparing a perovskite film or a solar cell. The method includes: placing a substrate coated with the perovskite precursor film on a hot plate, the hot plate being in direct contact with the back face of the substrate; controlling the evaporated amount and residual amount of the solvent in the perovskite precursor film by controlling the temperature of the hot plate and the heating duration, so that the perovskite materials are crystallized into perovskite grains to form a perovskite intermediate-phase film; placing the perovskite intermediate-phase film on the permeable membrane with the back face of the substrate facing upward, continuing with heating, so that adjacent perovskite grains merge with each other; and raising the temperature of the hot plate and continuing with heating so that the perovskite grains form a perovskite light-absorbing layer.

Abstract: A process to produce dense nanocrystalline composites such as ceramic bodies, coatings and multi-layered devices with uniform microstructure is disclosed. The invention utilizes sol-gel solutions to reduce agglomeration of nanocrystalline powders in the production of “green bodies” or intermediate products. This novel use of sol-gel solutions also reduces grain growth and porosity in products during sintering. In finished products, final grain sizes are typically less than 100 nm with densities of the final products approaching 99.5% of theoretical densities. In addition, sintering temperatures required are lower than those in conventional methods, typically less than 1,100° C. While FIG. 1 shows one application of this novel process, this invention has wide application in the manufacture of many other products, particularly for composite coatings and in the production of nanodevices.

Abstract: A process to produce dense nanocrystalline composites such as ceramic bodies, coatings and multi-layered devices with uniform microstructure is disclosed. The invention utilizes sol-gel solutions to reduce agglomeration of nanocrystalline powders in the production of “green bodies” or intermediate products. This novel use of sol-gel solutions also reduces grain growth and porosity in products during sintering. In finished products, final grain sizes are typically less than 100 nm with densities of the final products approaching 99.5% of theoretical densities. In addition, sintering temperatures required are lower than those in conventional methods, typically less than 1,100° C. While FIG. 1 shows one application of this novel process, this invention has wide application in the manufacture of many other products, particularly for composite coatings and in the production of nanodevices.