Charge Carrier Transport Properties of Vacuum Evaporated Anthrylvinylbenzene Thin Films

Abstract

The charge carrier conduction processes and dielectric properties of two new materials based on anthracene core structure, 1-(9 anthrylvinyl)-4-benzyloxybenzene (AVB) and 1,4- bis(9-anthrylvinyl)benzene (AV2B) diodes have been investigated using dc current density–voltage (J–V) and AC impedance spectroscopy (100 Hz–10 MHz). The DC electrical properties of ITO/anthracene derivative /Al device showing an ohmic behavior at low voltages and switches to space charge limited current (SCLC) conduction with exponential trap distribution at higher voltages. The best performance device was achieved from ITO/AVB/Al structure showing the high charge carrier mobility which has also been evaluated from SCLC as 6.55´10-6 cm/Vs. According to the impedance spectroscopy results the structures were modeled by equivalent circuit designed as a parallel resistor Rp and capacitor Cp network in series with resistor Rs. The evolution of the electrical parameters with frequency and bias voltage of these anthracene-based systems has been discussed. The conductivity s(w) evolution with frequency and bias voltage was studied for ITO/anthracene derivatives/Al devices. The dc conductivity sdc for these devices has been determined. The ac conductivity sac showed a variation in angular frequency as A.ws with a critical exponent s< 1 suggesting a hopping conduction mechanism at high frequency