Molecular mechanism of rigidity- and planarity-promoted, state-dependent doping of conjugated ladder-type molecules. (3rd October 2022)

• Record Type: Journal Article
• Authors: Lee, Jongbok; Li, Shi; Ji, Xiaozhou; Che, Sai; Cao, Yirui; Tabor, Daniel P.; Fang, Lei
• Is Part Of: Materials chemistry frontiers. Volume 6:Number 22(2022)
• Page Start: 3329
• Page End: 3337
• Publication Date: 2022-10-03
• Subjects: Materials science -- Periodicals; Chemistry -- Periodicals; 540
• DOI: 10.1039/d2qm00789d
• Languages: English
• ISSNs: 2052-1529

Abstract

Abstract : We report the synthesis and analysis of a series of conjugated ladder-type heteroarene model π-donor compounds, followed by computational and experimental mechanistic investigations of their π–π interactions and doping processes with the electron-deficient dopant F4 TCNQ. Abstract : Determining the doping mechanism of organic semiconductors (OSCs) using neutral dopants, whether through the formation of an ion-pair (IP) or a charge transfer complex (CTC), remains an open challenge. It is hypothesized that the rigidity and planarity of the π-backbone of OSCs can significantly impact their doping mechanism and efficiency. In this work, a series of fused-ring ladder-type small molecules (B-ICz, Th-ICz, and BDT-ICz ) are synthesized as models to investigate this hypothesis. Upon mixing with the electron-deficient dopant F4 TCNQ, each of these compounds shows dominant IP formation in solution whereas both IPs and CTCs are observed in the solid-state. Control experiments and computational investigations reveal that the extended, rigid, and coplanar π-faces of these ladder-type molecules are essential to facilitate the doping interaction with F4 TCNQ, for both IP and CTC mechanisms. This work provides principles for the future rational design of molecular structures of OSCs and dopants for electronic doping purposes.