Pyrrole-Containing Semiconducting Materials: Synthesis and Applications in Organic Photovoltaics and Organic Field-Effect Transistors.

Organic semiconducting materials derived from π-electron-rich pyrroles have garnered attention in recent years for the development of organic semiconductors. Although pyrrole is the most electron-rich five-membered heteroaromatic ring, it has found few applications in organic photovoltaics and organic field-effect transistors due to synthetic challenges and instability. However, computational modeling assisted screening processes have indicated that relatively stable materials containing pyrrolic units can be synthesized without compromising their inherent electron-donating properties.

Thieno[3,2-]pyrrole and Benzo[][1,2,5]thiadiazole Donor-Acceptor Semiconductors for Organic Field-Effect Transistors.

Two p-type donor-acceptor (D-A) semiconducting small molecules were synthesized to investigate the effect of the backbone curvature on the organic field-effect transistor performance. The backbone curvature of the donor-acceptor small molecules was modified by changing the spacer group from bithiophene to thienothiophene. Bithiophene to thienothiophene spacer groups were placed between 4-thieno[3,2-]pyrrole (donor) and benzo[][1,2,5]thiadiazole (acceptor) to generate and donor-acceptor molecules.

Incorporation of Thieno[3,2-]pyrrole into Diketopyrrolopyrrole-Based Copolymers for Efficient Organic Field Effect Transistors.

Recent advancements in organic field effect transistors have switched chemists' focus from synthesizing libraries of organic semiconductors to a more targeted approach where chemical alterations are performed on known semiconductors to further improve electronic properties. Among successful semiconducting polymer candidates, copolymers based on diketopyrrolopyrrole-and thieno[3,2-]thiophene [] have been subjected to modifications on the diketopyrrolopyrrole unit by using flanking groups and side chain engineering. Thieno[3,2-]thiophene moiety, however, has seen minimal modifications due to the limited number of modifying sites.

Thieno[3,2- b]pyrrole-benzothiadiazole Banana-Shaped Small Molecules for Organic Field-Effect Transistors.

We report two banana-shaped organic semiconducting small molecules containing the relatively unexplored thieno[3,2- b]pyrrole with thiophene and furan flanked benzothiadiazole. Theoretical insights gained by DFT calculations, supported by single crystal structures show that furan flanked benzothiadiazole-thieno[3,2- b]pyrrole small molecule has a higher curvature compared to the thiophene flanked small molecule due to the shorter carbon-oxygen bond in furan. Despite similar optical and electrochemical properties, thiophene flanked small molecule shows average hole mobility up to 8 × 10 cm V s, however furan flanked small molecule performs poorly in thin film transistor devices (μ ≈ 5 × 10 cm V s).