Chemical to solid modification in oligothiophene and related materials

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New semiconducting materials based on organic molecules promise to allow for the creation of devices with properties unlike those made from traditional materials.  For example, the new "OLED" televisions boast thinner profiles and lower power consumption than older TV types.  Other advantages to these materials are greater flexibility, lighter weight, and lower manufacturing costs.  Although certain organic devices are on the market already, the promise of additional applications drives new research.  Our niche in the worldwide research effort is the relationship between the structure of the molecule and its solid, and how that impacts device performance.  In this way, we aim to create "designer electronics", where the electronic properties of the semiconductor (the active material) can be made-to-order using chemical modifications on the molecules that make the material.  Ultimately, the research will open the way to new devices that are more effective, cheaper, use less energy, and contain less toxic elements.  Thus, they could be called "green devices" and lead to more sustainable technologies.   Oligothiophenes are one type of organic semiconductor, based on a thiophene ring (a pentagon of five atoms - four carbons and one sulfur) repeated several times. This ring's stability and the different reactivities of its carbons make it an attractive target for modifications to change its properties, e.g., electron-withdrawing groups change its mode of conductivity from p-type (positive) to n-type (negative charge carriers). Similarly, modification to the oligothiophene unit can change its orientation relative to the surface.  A perpendicular orientation gives good field-effect conductivity, of use in circuit devices, while parallel orientation is ideal for light harvesting (needed for solar cells).   We will also be looking at the development of sustainable synthetic routes to these molecules, i.e., new methods of synthesis that minimize environmental impact and energy consumption.