"Toshiba, the Japanese world-leader in development of perovskite photovoltaic modules for next-generation solar power generation, has developed a new coating method for the perovskite layer that boosts power conversion efficiency (PCE) to 15.1% for Toshiba’s 703cm^2 module, the highest for any large, polymer film-based perovskite photovoltaic module. The innovative coating method for perovskite layer also greatly reduces production time and costs, contributing to a lower cost for solar power generation."
"Success in achieving carbon neutrality will require much greater use of photovoltaic power generation, and a significant expansion in locations where photovoltaic modules can be installed. Today’s most widely used photovoltaic modules are made with crystalline silicon and are heavy, and this, plus their rigidity, limits where they can be installed. The polymer film-based perovskite photovoltaic module is an attractive next-generation alternative, as it is thin, light and flexible, and can be installed in locations where it is difficult to use silicon photovoltaic modules, such as low load-bearing roofs and office windows. Recent improvements in the PCE of perovskite photovoltaic modules has brought them to a level comparable to that of silicon photovoltaic modules."
"Toshiba’s latest breakthrough is the development of a new perovskite layer coating method. The company previously developed a two-step coating process that first applied a layer of PbI2 (lead iodide) ink to a substrate, followed by a layer of MAI (methyammonium iodide, CH3NH3I) ink, triggering a reaction that formed an MAPbI3 layer. However, this multi-step approach had a low coating rate and often left unreacted sections in the perovskite layer (Figure 1, left). The alternative is a one-step process that applies MAPbI3 ink directly, but it is not easy to control crystallization of the MAPbI3 and obtain a uniform perovskite layer across a large area (Figure 1, right). A new coating method that solves these problems was required."
"Toshiba has developed a one-step meniscus coating method that uses improved ink, film drying processes and production equipment to form a uniform perovskite layer over an area as large as 703cm^2. These innovations halve the steps for deposition of the perovskite layer, and raise the coating speed to 6 meters per minute on a 5×5 cm^2 module, a rate that meets requirements for mass production (Figure 2, left)."
"Applied to Toshiba’s previously reported 703cm^2 polymer film-based perovskite photovoltaic modules, the one-step meniscus coating method achieves a PCE of 15.1%, the world's highest ever for a polymer film-based large-area perovskite photovoltaic module. (Figure 2, right). This higher PCE and the faster, simplified production process, significantly advance progress toward the commercialization of highly efficient, low-cost, polymer film-based perovskite photovoltaic modules."
"Toshiba’s printing technology for the production of film-based perovskite solar cell modules involves forming the substrate with a resin film, such as polyethylene terephthalate. It uses a planar inverted structure that can be produced at a temperature below 150 degrees Celsius for the cell structure. The company managed to form a uniform thin layer of methylammonium lead iodide by utilizing a meniscus printing technology that is developed by conducting research on organic thin-film solar cells. It is said that this improves the efficiency of panels by lowering the degree to which the cells vary from each other."
"The flexible and lightweight panel is indicated by Toshiba as suitable for locations where it is difficult to install conventional crystalline silicon modules, such as low-load-bearing roofs and office windows. “Toshiba estimates that the new perovskite photovoltaic modules would generate power equivalent to two-thirds of the annual power consumption by homes in Tokyo if installed on a roof area of 164.9km^2, roughly equal to the roof surface area of all buildings in Tokyo,” the manufacturer further explained."
"Toshiba will continue research on perovskite photovoltaic modules, aiming to increase PCE to 20% or more, and to enlarge the active area to 900cm2, the size required for practical application. The company estimates achieving these targets will cut the manufacturing cost of perovskite photovoltaic modules to \15/W (approx. $0.14/W)."
"The newly developed coating technology and the perovskite solar modules that apply it are research results under a New Energy and Industrial Technology Development Organization (NEDO) project, Development of Technologies to Promote Photovoltaic Power Generation as a Main Power Source."
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