Highly Deformable Optoelectronics Using Liquid Metal

The study proposes optoelectronics based on liquid metal and photo-switchable ionic liquid with liquid-liquid heterojunction technology. As a proof of concept, a liquid-state light sensor and an optical memory which is switched on and off by UV and blue light exposures were demonstrated. The ionic liquid named 1-butyl-3-(4-phenylazobenzyl)imidazolium bis(trifluoromethanesulfonyl)amide ([Azo][NTf2]) is used to realize functions as a light sensor or an optical memory. This ionic liquid is photoresponsive and can undergo a reversible isomerization controlled by light irradiation of UV or Blue; this property was used to realize the liquid-state optoelectronics in this study. In addition, a liquid-state heterojunction was taken advantage of in interconnects between sensing ionic liquid and liquid metal. The liquid-state heterojunction in the microchannels was critical to preventing intermixing of the two liquid components, especially, when the completed devices underwent mechanical deformation. These two important technologies, the photo-switchable ionic liquid and the heterojunction, achieved liquid-state optoelectronics based on liquid materials.