A-D-A Type Semiconducting Small Molecules with Bis(alkylsulfanyl)methylene Substituents and Control of Charge Polarity for Organic Field-Effect Transistors

Sung Joon Cho; Min Je Kim; Ziang Wu; Jae Hoon Son; Sang Young Jeong; Sungjoo Lee; Jeong Ho Cho; Han Young Woo

doi:10.1021/acsami.0c11561

A-D-A Type Semiconducting Small Molecules with Bis(alkylsulfanyl)methylene Substituents and Control of Charge Polarity for Organic Field-Effect Transistors

ACS Appl Mater Interfaces. 2020 Sep 16;12(37):41842-41851. doi: 10.1021/acsami.0c11561. Epub 2020 Sep 3.

Authors

Sung Joon Cho¹, Min Je Kim², Ziang Wu¹, Jae Hoon Son¹, Sang Young Jeong¹, Sungjoo Lee³, Jeong Ho Cho², Han Young Woo¹

Affiliations

¹ Department of Chemistry, Korea University, Seoul 136-713, Republic of Korea.
² Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul 03722, Republic of Korea.
³ SKKU Advanced Institute of Nanotechnology (SAINT), Department of Nano Engineering, Sungkyunkwan University, Suwon 440-746 Korea.

PMID: 32819095
DOI: 10.1021/acsami.0c11561

Abstract

In this study, we synthesize four different kinds of bis(alkylsulfanyl)methylene-substituted 4,9-dihydro-s-indaceno[1,2-b:5,6-b']dithiophene (IDT)-based acceptor-donor-acceptor (A-D-A) type small molecules (IDSIC, IDSIC-4F, IDSIC-4Cl, and IDSTIC) by incorporating electron-withdrawing halogen atoms or electron-releasing thiophene spacers. Herein, enhanced structural planarity and crystalline intermolecular packing are induced by the sp²-hybridized C═C double bond side chains and sulfur-sulfur chalcogen interactions. The fine control of intramolecular charge transfer modulates the electrochemical characteristics and the resulting carrier polarity in organic field-effect transistors (OFETs). Well-balanced ambipolar, n-dominant, and p-dominant charge transport properties are successfully demonstrated in OFETs by modulating the electron-donating or withdrawing strength based on the A-D-A structural motif, resulting in hole/electron mobilities of 0.599/0.553, 0.003/0.019, 0.092/0.897, and 0.683/0.103 cm²/V·s for IDSIC, IDSIC-4F, IDSIC-4Cl, and IDSTIC respectively, after thermal annealing at 200 °C. Thermal annealing of the as-cast films improves the intermolecular packing in an edge-on fashion, which is investigated in detail by grazing incidence X-ray scattering. Finally, complementary logic circuits, i.e., NOT, NAND, and NOR, are fabricated by assembling p-dominant IDSTIC and n-dominant IDSIC-4Cl OFETs. Therefore, a simple and efficient molecular design strategy for fine tuning the charge polarity and charge transport properties of OFET devices is presented.

Keywords: A-D-A structure; OFET; ambipolar transistor; charge polarity; organic field-effect transistor.