Vinyl-Flanked Diketopyrrolopyrrole Polymer/MoS2 Hybrid for Donor–Acceptor Semiconductor Photodetection

• Published in: Chemistry of materials Vol. 35; no. 12; pp. 4691 - 4704
• Main Authors: Wahalathantrige Don, Ranganath, Das, Priyanka, Ma, Ziyuan, Kuruppu, Udara M., Feng, Daijun, Shook, Brian, Gangishetty, Mahesh K., Stefan, Mihaela C., Pradhan, Nihar R., Scott, Colleen N.
• Format: Journal Article
• Language: English
• Published: American Chemical Society 27.06.2023
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/acs.chemmater.3c00211

Polymers containing the 1,4-diketo-pyrrolo­[3,4-c]­pyrrole (diketopyrrolopyrrole, DPP) unit are highly desirable for optoelectronic devices. However, the requirements for the substituents flanking the DPP unit at the 3,6-positions are limited to aryl groups due to the lack of synthetic methods to prepare other substituted DPP. This paper describes the synthesis, characterization, and application of the first vinyl-flanked DPP polymers: DPP-vinyl-thiophene-vinyl (PDPPVTV) and DPP-vinyl-thiophene-thiophene (PDPPVTT). The position of the vinyl group is varied to determine its effect on the physical and optoelectrical properties of the polymers. The semicrystalline polymers record moderate molecular weights (M n ∼ 25–30 kDa), good solubility in chloroform, and high thermal stabilities (T d onset ∼ 400 °C). Both polymers have broad absorption bands in the solid state (abs λmax ∼ 800 nm) that extend into the near-infrared (NIR) region (900–1000 nm). PDPPVTT has two orders of magnitude higher hole mobility than PDPPVTV (0.25 vs 0.0018 cm2 V–1 s–1) and is used as a coating material in a MoS2 FET device. The PDPPVTT/2D MoS2 hybrid device shows higher photoresponsivity in the NIR region (103 A/W at 800 nm and 102 A/W at 1050 nm) than the pristine MoS2 photodetector (102 A/W at 800 nm and 0 A/W at 1050 nm).