A solution-processed oxide thin film transistor (TFT) with low operating voltage is demonstrated using a high dielectric constant Gd2O3 gate insulator. Prepared using spin coating followed by annealing at 400 degrees C, the Gd2O3 film exhibits a dielectric constant in the range of 10-12 with a breakdown field as high as 3.5 MV cm(-1). A proper amount of polymeric agent, polyvinylpyrrolidone (PVP), is very important to access uniform film growth, a smooth surface morphology, and a low leakage current, while the annealing temperature and film thicknesses are important as well for the operational solution-processed gate insulator. The resultant Zn-Sn-O/Gd2O3 TFT exhibits enhanced performance with a field-effect mobility of similar to 2.53 cm(2)V(-1) s(-1) by a factor of 8.7 compared with the TFTs using a SiO2 insulator with an exceptionally low operating voltage < 10 V. (C) 2013 Elsevier B. V. All rights reserved.