Fused-ring Pyrrole Organic Semiconductors for Organic Field Effect Transistors

Friday, April 9, 2021

Dr. Mihaela C. Stefan

Department of Chemistry and Biochemistry, Department of Bioengineering

University of Texas at Dallas

Friday, April 9th 2021 at 3:30 PM in Hand 1100

Abstract:  The smallest S, N-heteroacene, thieno[3,2-b]pyrrole is a good building block for organic semiconductors due to the high electron density, asymmetry, and easily modifiable NH group.  Our group have shown that organic semiconductors from thieno[3,2-b]pyrrole display “nearly-ideal” OFET characteristics without compromising charge carrier mobilities or threshold voltages. We have varied the structure and topology to investigate the relatively under-explored banana shape thieno[3,2-b]pyrrole ole semiconductors and the influence of the heteroatom.

Banana shaped donor-acceptor molecules with benzothiadiazole, fluorinated benzothiadiazole acceptors and thieno[3,2-b]pyrrole donor  (TP-BT2T-BT and TP-FBT2T-TP) have been reported by our group and the OFET parameters were evaluated in a bottom-gate/bottom-contact (BGBC) OFET architecture. Hole mobility of 0.08 cm2 V-1 s-1 was measured for the molecule (TP-BT2T-BT) with benzothiadiazole as the acceptor. The molecule containing fluorinated benzothiadiazole (TP-FBT2T-BT) showed hole mobility of 1.57×10-3 cm2 V-1 s-1.

Lengthening conjugation by synthesizing conjugated polymers was employed to facilitate the hole transport and to obtain comparatively stable semiconductors. Our group reported the donor-acceptor polymer containing thienopyrrole donor and diketopyrrolopyroole acceptor, P(DPP-TP) and the OFET parameters were evaluated with bottom-gate/top-contact (BGTC) OFET architecture. An increase in hole mobility to 0.12 cm2 V-1 s-1 was observed for the polymer (P(DPP-TP)) as compared to the conjugated small molecules.

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