Flexible and Transparent Cu Electronics by Low-Temperature Acid-Assisted Laser Processing of Cu Nanoparticles

Copper is a promising electronic material due to low cost and high electrical conductivity. However, the oxidation problem in an ambient condition creates a crucial issue in practical applications. In this paper, a simple and cost-effective Cu patterning method has been developed on flexible PET film by combining a solution processable Cu nanoparticle patterning and a low-temperature postprocessing with acetic acid treatment, laser sintering process, and acid-assisted laser sintering process. The acid-assisted laser sintering processed Cu electrode shows superior characteristics in electrical, mechanical, and chemical stability over other postprocessing methods. Finally, the Cu electrode is applied to flexible electronics applications such as flexible and transparent heaters and touch screen panels.J.K. and H.C. contributed equally to this work. This work was supported by Global Frontier R&D Program on Center for Multiscale Energy System (grant no. 2012-054172) and Creative Materials Discovery Program (NRF-2016M3D1A1900035) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future, and the R&D Convergence Program