| Organic devices have shown great promise during the past decade. These devices have several advantages including light weight, flexibility, ease of manufacturability and low cost. These pros make the organic devices good candidates to replace the current semiconductor technology in the areas of thin film transistors, photovoltaics and light-emitting diode fabrication. Pentacene as a conjugated compound shows high performance (including high carrier mobility) among many organic compounds. In contrast to the high electrical performance, these materials suffer from photo-oxidation, a phenomenon in which the devices degrade over time.;In this thesis five novel derivatives of pentacene are introduced and electrically characterized. These compounds were synthesized at the University of New Hampshire in Dr. Glen Miller's research group. Later the compounds were given to us for the electrical characterization. All these materials are photo-oxidation resistant. The photo-oxidation resistance of these compounds varies as a function of the substituent. As reported by Dr. Miller et al. the type and the position of the substituent also affect the HOMO-LUMO energies.;The electrical behavior of the transistors made out of three of the derivatives is similar to that of conventional transistors. The differences between their electrical behavior and that of the conventional transistors are also discussed. The electrical characteristics of the other two compounds are suppressed by contact effects. This type of electrical behavior in organic semiconductor is not thoroughly investigated in the literature. In this thesis possible carrier injection methods that result in this type of electrical characteristic are discussed. The last part of this thesis compares the electrical performance (including carrier mobility, threshold voltage and ON/OFF ratio) of these compounds to some other derivatives of pentacene reported in the literature. |
