Tunable electrical conductivity in oriented thin films of tetrathiafulvalene-based covalent organic framework

Journal Article · Tue Sep 16 00:00:00 EDT 2014 · Chemical Science

DOI:https://doi.org/10.1039/c4sc02593h· OSTI ID:1211281

Cai, SL; Zhang, YB; Pun, AB; He, B; Yang, JH; Toma, FM; Sharp, ID; Yaghi, OM; Fan, J; Zheng, SR; Zhang, WG; Liu, Y

Despite the high charge-carrier mobility in covalent organic frameworks (COFs), the low intrinsic conductivity and poor solution processability still impose a great challenge for their applications in flexible electronics. We report the growth of oriented thin films of a tetrathiafulvalene-based COF (TTF-COF) and its tunable doping. The porous structure of the crystalline TTF-COF thin film allows the diffusion of dopants such as I-2 and tetracyanoquinodimethane (TCNQ) for redox reactions, while the closely packed 2D grid sheets facilitate the cross-layer delocalization of thus-formed TTF radical cations to generate more conductive mixed-valence TTF species, as is verified by UV-vis-NIR and electron paramagnetic resonance spectra. Conductivity as high as 0.28 S m(-1) is observed for the doped COF thin films, which is three orders of magnitude higher than that of the pristine film and is among the highest for COF materials.

• Sponsoring Organization: USDOE Advanced Research Projects Agency - Energy (ARPA-E)
• DOE Contract Number: DE-AR0000251
• OSTI ID: 1211281
• Journal Information: Chemical Science, Vol. 5, Issue 12; ISSN 2041-6520
• Country of Publication: United States
• Language: English