We used a high dielectric constant material, hafnium dioxide (HfO2), as the dielectric layer and N,N'-ditridecyl-3,4,9,10-perylene tetracarboxylic diimide (PTCDI-C13) as the active layer to fabricate low voltage-driven organic thin-film transistor (OTFT) devices. After modifying the surface of HfO2 by polyimide (PI), the electrical characteristics and stability of PTCDI-C13-based OTFTs were considerably improved. We observed that the insulating property of HfO2/PI was superior to HfO2. The microstructures of PTCDI-C13 grown on HfO2/PI were better than those grown on HfO2, resulting from smaller interfacial tension of PTCDI-C13 with PI than with HfO2. The interfacial trap density of PTCDI-C13 with HfO2/PI is less than PTCDI-C13 with native HfO2. Consequently, the devices with HfO2/PI showed enhanced electrical performance compared than those with HfO2.