We report the interface properties of a perylene-diimide thin film between Au and n-Si substrate fabricated by the spin coating method. The relaxation time (τ) and interface trap density (Dit) characteristics of the fabricated structure were obtained across various voltage ranges (0.0 V–300 mV) and various frequency ranges (1 kHz–1 MHz). We observed a peak in Git/ω versus log (f) plots from 0.0 V to 300 mV. This peak shows the presence of the interface state and its relaxation time. We observed a decrease in values at the same time as an increase in Nss values with the increasing applied voltage for the sample. The Nss and τ values found to be in the ranges 1.50 × 1012 eV−1 cm−2–2.83 × 1012 eV−1 cm−2 and 2.83 × 10−6 s–4.82 × 10−7 s between 0.0 V and 0.3 V, respectively.