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.

Among the various next-generation solar cells, a perovskite solar cell can solve the economic problem because it can perform the low temperature solution process and the material is inexpensive. Photovoltaic conversion efficiency is comparable to silicon solar cells and thin-film solar cells. However, to commercialize the perovskite solar cells, there are many problems to be resolved, such as stability, upscaling, and efficiency. Thus, in this study, perovskite crystallization experiments were conducted according to the coating conditions such as the coating speed of the meniscus solution sheared coating process, and large-area perovskite solar cells with p-i-n structures were fabricated. Perovskite crystallization is one of the crucial factors that determine the efficiency of solar cells, and it is an integral process condition for manufacturing large-area perovskite solar cells.

Solid oxide fuel cells (SOFCs) are at a technological level close to commercialization, which could be enabled by new material research. Especially, not only an electrolyte, but also a cathode material becomes very important to further increase electrochemical performance, due to the effort to lower operating temperature of SOFCs to intermediate range (400-600℃) to take advantage of high and low temperature operation. Unfortunately, this trend inevitably results in demand for new cathode materials with high oxygen reduction reaction activity, as well as high mechanical durability. Recently, ceramic materials which conduct oxygen ion, proton, and electron, thereby called ‘triple conducting oxide’ are being highlighted, due to their excellent material properties, to be used for cathodes of SOFCs. This paper reviews the three representative triple-conducting oxides, which were already used and tested in SOFC operating conditions.