Effect of SiO2 buffer layer on thermoelectric response of In2O3/ITO thin film thermocouples

Abstract

Thin film thermocouples can be applied in in-situ temperature measurement. Herein, the flexible In2O3/ITO thin film thermocouples accompanying with the excellent thermoelectric response were prepared by using radio-frequency magnetron sputtering method. A SiO2 buffer layer was accreted between the flexible polyimide substrate and the thermocouples. The effects of the SiO2 buffer layer on morphology, optical transmission, resistances and thermoelectric response of thin film thermocouples were systematically studied. The results show that the resistances of In2O3/ITO thin film thermocouples with SiO2 buffer layer exhibited a consistent trend with the increasing of bending cycles. Under the bending strain of 0.13%, an average Seebeck coefficient was 171.7 μV/°C for the thin film with the SiO2 layer, which was 2.8 times than the film without SiO2 layer. This work presents a great potential for achieving high thermoelectric response of thin film thermocouples, and it also provides an interesting insight of flexibility and bending strain through buffer layer accretion.