The team led by Dr. Jin-Kyu Kang at DGIST's Division of Energy Technology developed the flexible copper zinc tin sulfur-selenium CZTSSe thin film solar cell using a non-toxic chalcogenic materials.
Flexible thin-film solar cell can be applied in various fields such as wearable, building, and automobiles based on the flexible substrate technology and CZTSSe thin film solar cells use low-cost, ecofriendly materials such as copper, zinc and tin rather than CIGS, CdTe or perovskite materials used in other thin film solar cells or heavy metals such as indium, lead, and cadmium.
However the photoelectric conversion efficiency of CZTSSe had not exceeded 10 percent as a result of the spread of impurities inside the flexible substrate and delamination, although Solar Frontier in Japan claimed an efficiency of 12.6 prcent for a CZTSSe thin film solar cell in 2013 developed with IBM. Solar Frontier has also developed a cadmium free CIGS thin film solar cell with an efficiency of 23.6 percent.
The higher efficiency of the DGIST cell comes from changing the existing 3-stack structure of CZTSSe thin film solar cell precursor into a multi-layered structure and by improving the voltage characteristics and uniformity. Moreover, it has the problem with uniformity degradation when a large-area process is applied to the cell, but applied process technology in this research improved not only efficiency but also uniformity.
"Our research achievement has presented ways to secure the uniformity of large-area process, which can cause issues in commercialization. We will be able to advance the commercialization of next generation solar cell which is applicable in various fields such as building outer walls," said Dr. Kee-Jeong Yang who led the process technology development.
"As there is growing interest towards environment and resources are used unlimitedly these days, it is a very meaningful achievement that we have developed a thin-film solar cell using widely available, ecofriendly materials. We plan to lead the future solar cell technology using widely available