AbstractMultiple functionality of tungsten polyoxometalate (POM) has been achieved applying it as interfacial layer for solution processed high performance In₂O₃ thin film transistors, which results in overall improvement of device performance. This approach not only reduces off-current of the device by more than two orders of magnitude, but also leads to a threshold voltage reduction, as well as significantly enhances the mobility through facilitated charge injection from the electrode to the active layer. Such a mechanism has been elucidated through morphological and spectroscopic studies.