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The main goals of this SEED project are to control the electronic properties of semiconducting polymers by molecular organization and the engineering of the gate dielectric in ambipolar conjugated polymer Field Effect Transistors (FETs). Molecular organization is achieved by the design and synthesis of well-defined polymer structures which incorporate neutral and charged functional groups at precise locations along the backbone. The gate dielectric layer in ambipolar polymer FET (see figure below) will be optimized by controlling the interfacial phenomena associated with organic semiconductors. Recent result from the Heeger group shows that it is possible to fabricate ambipolar light emitting FETs (LEFETs) from conjugated polymers. However, the device performance can be improved considerably. In this SEED project, we will focus on: (i) the design and characterization of conjugated oligomers with surface-specific functionalities for creating monolayers which improve charge injection from electrodes into the channel of polymer FETs and which improve the carrier mobility and the carrier density within the FET channel, and (ii) the synthesis and characterization of new semiconducting polymer materials with bipolar charge transport characteristics to improve the performance of ambipolar polymer FETs. 
(Left) Schematic representation of the ambipolar conjugated polymer FET. (Right) Transfer scan (Id vs. Vg) for the SY LEFET along with the corresponding emitted light intensity vs. Vg. The emission zone is located in the channel: a) near the Ca source electrode, b) near the center of the channel, and c) near the Ag drain electrode. |
