Abstract
Most covalent organic frameworks (COFs) to date are made from relatively small aromatic subunits, which can only absorb the high-energy part of the visible spectrum. We have developed near-infrared-absorbing low bandgap COFs by incorporating donor acceptor-type isoindigo- and thienoisoindigo-based building blocks. The new materials are intensely colored solids with a high degree of long-range order and a pseudo-quadratic pore geometry. Growing the COF as a vertically oriented thin film allows for the construction of an ordered interdigitated heterojunction through infiltration with a complementary semiconductor. Applying a thienoisoindigo-COF:fullerene heterojunction as the photoactive component, we realized the first COF-based UV- to NIR-responsive photodetector. We found that the spectral response of the device is reversibly switchable between blue- and red-sensitive, and green- and NIR-responsive. To the best of our knowledge, this is the first time that such nearly complete inversion of spectral sensitivity of a photodetector has been achieved. This effect could lead to potential applications in information technology or spectral imaging.
Item Type: | Journal article |
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Faculties: | Chemistry and Pharmacy > Department of Chemistry |
Research Centers: | Center for NanoScience (CENS) |
Subjects: | 500 Science > 540 Chemistry 500 Science > 500 Science |
ISSN: | 0002-7863 |
Language: | English |
Item ID: | 54178 |
Date Deposited: | 14. Jun 2018, 09:55 |
Last Modified: | 04. Nov 2020, 13:33 |