32 KOREA CHALLENGE The efficiency of perovskite solar cells, which are price-competitive and offer flexibility, translucency, and lightness, needs to be improved so they can compete with silicon solar cells. Unlike conventional silicon solar cells, perovskite solar cells can be used in the emerging window-type and portable solar cell market. INNOVATION A research team at the Korea Research Institute of Chemical Technology has produced large modules through a printing process. It has successfully fabricated high efficiency modules with an efficiency level of over 15% (based on active areas) that exhibit heat stability for 1,000 hours at 85°C, as well as excellent 03 DEVELOPMENT OF FABRICATION OF A HIGHLY EFFICIENT AND LARGE- AREA PEROVSKITE PHOTOVOLTAIC MODULE USING A PRINTING PROCESS SECTION 02 33 performance after 50 heat cycles (-45°C – 85°C). This makes these cells longer lasting and more efficient than previous generations. ACTION The project has broken the world record for perovskite solar cell efficiency five times and most recently achieved an efficiency level of 22.7% on a unit cell in October 2017. This efficiency level is on par with those of conventional silicon solar cells and higher than the 22.1% and 22.6% maximum efficiency levels of cadmium telluride (CdTe) in thin film solar cells and copper indium gallium selenide (CIGS) solar cells. A 20.9% efficiency level was also confirmed on a unit cell created as part of the effort to secure enlargement technology. The team is currently working on optimising the module production process to minimise areas of loss and make them longer lasting. POTENTIAL The research team applied high- efficiency technologies in producing large modules through a printing process. It is expected that applying roll-to-roll processing, a production method that allows for rapid mass production at low cost, will revolutionise the dissemination of solar cells in the future. RENEWABLE ENERGY