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

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.