Papers by Author: Iulia Salaoru

Abstract: In recent years, the interest in the application of organic materials in electronic devices (light emitting diodes, field effect transistors, solar cells), has shown a rapid increase. Polymer memory devices (PDMs) is a very recent addition to the organic electronics. The polymer memory devices can be fabricated by depositing a blend (an admixture of organic polymer, small organic molecules and metal or semiconductor nanoparticles) between two metal electrodes. We demonstrate the memory effect in the device with simple structure based on blend of polymer with different materials like ionic compound (NaCl), ferroelectrical nano-particles (BaTiO3) and small organic molecules In 2007 Paul has proposed a model to explain memory effect a switching between two distinctive conductivity states when voltage is applied based on electrical dipole formation in the polymer matrix. Here, we investigate if our memory devices based on different types of materials are fitted with the proposed model.

Abstract: Intensive research is currently underway to exploit the highly interesting properties of nano-sized particles and organic molecules for optical, electronic and other applications. Recently, it has been shown that nano-sized particles and small organic molecules embedded in polymer matrices can be used to realise memory devices. Such memory devices are simple to fabricate via the spin-on technique. This work presents an attempt to use sea salt, embedded in polyvinyl acetate, in the making of the memory devices. A polymer blend of polyvinyl acetate and sodium chloride (NaCl) was prepared in methanol and spin coated onto a glass substrate marked with thin Al tracks and a top contact was evaporated onto the blend after drying - this resulted in a metal-organic-metal (MOM) structure. The current-voltage (I-V) behaviour of MOM devices shows that the devices can be switched from a high conductivity state to a low conductivity state, by applying an external electric field - this property can be exploited to store data bits. The possible charging mechanism, based on the electric dipole formation, is presented in this work. Polymer blends of polyvinyl acetate with nano-particles of BaTiO3 are also investigated to further our understanding of charging mechanism(s).