The influence of external electric fields on the vibrational properties of Pentacene-based field effect transistors were investigated by Ramanspectroscopy.ThemonitoredRamanbandswereintherangefrom 1100cm−1 to1200cm−1,whereabroadbandispresentandenhanceddue to the external electric field. The process is modeled by density functional theory (DFT) at the B3LYP/3–21G level. Additionally, the relaxation of the Raman bands after the removal of the external field was determined from an exponential Debye like decay fitting to be approximately 94 min, this finding indicates that a long relaxation time ca. 8 h is required in order to recover the original structure. Experimentally and theoretically was demonstrated that the applied electric fields induce artificial traps in the organic layer mediated by charge carrier–dipole interaction.