Oxygen Effects on Performance of Electrically Bistable Devices Based on Hybrid Silver Sulfide Poly(N-vinylcarbazole) Nanocomposites

An organic/inorganic bistable device is fabricated by using a simple spin-coating technique, in which the hybrid silver sulfide (Ag2S) poly(N-vinylcarbazole) (PVK) nanocomposite film is sandwiched between two electrodes. An obvious electrical hysteresis is observed in the current-voltage (I-V) curve of the device measured in the presence of different oxygen concentrations, and the magnitude of the electrical hysteresis is decreased with a decrease of the oxygen concentrations. The electrical bistability of the device exhibits a strong dependence on the oxygen concentrations, and the current variation of the OFF state is higher than that of the ON state with the gas atmosphere changing from N2 to air. Different theoretical models have been employed to describe the carrier transport mechanisms of the device in the OFF and ON states measured in different gas atmospheres on the basis of the experimental I-V results, and the carrier transport of the device in the ON state measured in air is very different from that measured in N2 and low O2 concentrations due to the participation of oxygen vacancies in the trapping and de-trapping processes of electrons into and out of the Ag2S/PVK heterointerface.