Among the types of new and renewable energy, perovskite solar cells, which are next-generation solar cells, are capable of a solution process at a low temperature of 200oC or less, and have the advantages of high efficiency and low cost; hence, many studies have been conducted. Research has been performed on perovskite solar cells mainly produced using spin coating, but they have a disadvantage of occurrence of pinholes and cracks when fabricated over a large area, reducing the uniformity and density of the thin film. For the production of large-area perovskite solar cells, research is underway using solution shearing process technology among printed electronic process technologies, and most of the processes have been carried out at low speeds. This is due to the size of the crystal, which is one of the most important factors of high efficiency of the solar cell. When printing at high speed for mass production, the size of the crystal is reduced, resulting in charge loss and lower efficiency, making it difficult to apply the roll-to-roll process. In this study, to apply the roll-to-roll process for mass production, perovskite crystallization experiments were performed under high-speed conditions and crystal size changes according to meniscus stability.

High-k dielectric thin films are widely applied in energy conversion/storage and information storage devices such as Dynamic Random access Memory (DRAM), Multilayer Ceramic Capacitor (MLCC), thermoelectric devices, etc. Among them, perovskite thin films, for instance, strontium titanate (STO) and barium titanate (BTO) are known to have extremely superior dielectric properties. Atomic layer deposition (ALD), can deposit thin films through atomic layering producing uniform and conformal high-k thin films with precise thickness control. While relatively low crystallinity of film quality due to low deposition temperatures of ALD can develop practical issues, they can be overcome by employing additional processes such as thermal annealing, plasma treatment, and seed layering. ALD, STO and BTO thin films treated with these additional processes demonstrate more improved crystallinity and electrical properties. In this paper, the processes to enhance properties of ALD high-k thin films, BTO and STO films are reviewed. Perspectives into high quality ALD high-k thin films as well as current efforts to further improve the film quality are discussed.