A joint research team of Professor Park Nam-gyu from the School of Chemical Engineering and Professor Kim Sang-woo from the School of Advanced Materials Sciences and Engineering has developed a device that converts mechanical energy into a direct current (DC) electrical energy for the first time. Previously, it was difficult to apply electric energy generated by friction to several technologies since it requires a power inverter that changes an alternating current (a type of electrical current where the direction switches back and forth) into a DC. The research team, however, discovered that the friction of halide perovskite materials (solar cells) and charge transport layer materials generates a DC. The difference in energy levels between the two materials makes an electrical junction, and this finally leads to DC generation. The electrical energy formed by this process can be used as an energy source of portable electric devices and also applied to skin wound treatments that utilize the movements of the human body. Moreover, putting pressure or illuminating lights on the generator can contribute to enhanced voltage and current output. Prof. Park hopes the DC generator will decrease the device size as the energy conversion efficiency improves. And Prof. Kim expects that this research will lead to better performances in skin wound care. The research was published in the renowned journal Energy & Environmental Science on January 5th.