Thermal shock resistance and enhanced adhesion of ITO film on organic substrate through introducing a transparent SiO2-PMMA buffer layer

Abstract

Transparent conductive films (TCFs) are widely used as electrodes in flexible optoelectronic devices, which have very strong potential applications in a lot of fields. Currently, one of the most intensively studied subject in this community is developing transparent organic buffer layer with both low thermal expansion coefficient and strong interfacial bonding energy with TCFs, so as to enhance their resistibility against thermal expansion during device working. This is particularly important for the ceramic type TCFs, such as indium tin oxide (ITO), because their thermal expansion coefficients are almost two orders of magnitude lower than that of flexible organic substrates. In this work, we have successfully developed a new highly transparent SiO2-PMMA buffer layer with glass transition temperature of 119.6 ℃. Thermal shock tests reveal that a 100 nm thick ITO film grown on this SiO2-PMMA buffer layer can tolerate 10 cycles of temperature shock between -55 ℃ and 120 ℃. In addition, the interfacial adhesion between organic substrate and ITO film after thermal shock was greatly enhanced as well by introducing SiO2-PMMA buffer layer. Our work presents the possible for ITO films to achieve the good thermal shock resistance and robust adhesion to organic substrates simultaneously, and is expected to be widely used in flexible optoelectronic devices.