Atomic Chalcogen Substitution Modulates Photophysical Properties and Electronic Structure in Donor–Acceptor Covalent Organic Frameworks
- 1Department of Chemistry and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität (LMU), Butenandtstraße 11(E), Munich, Germany, 81377
- 2Munich Data Science Institute, Technical University of Munich, Lichtenbergstr. 4, Garching b. München, Germany, 85748
- 3Department of Physics, Clarendon Laboratory, Parks Road, Oxford, United Kingdom, OX1 3PU
Abstract
While chalcogen substitution has recently emerged as a means for tuning the properties of covalent organic frameworks (COFs), its influence on the intrinsic photophysical and charge-transport properties of isoreticular donor–acceptor COFs remains largely unknown. Here, an isoreticular series of novel donor–acceptor COFs was constructed from a tetrathienonaphthalene-based (TTNTA) node and linear donor–acceptor–donor linkers containing oxygen (O), sulfur (S), or selenium (Se) within their acceptor cores. Highly crystalline COFs with identical topology and comparable structural order were obtained, while the synthesis of preferentially oriented thin films enabled direct comparison of chalcogen-dependent optoelectronic properties. Time-resolved photoluminescence measurements revealed progressively shorter emissive-state lifetimes from the O- to the S- and Se-containing COFs. Optical-pump terahertz-probe spectroscopy showed a parallel decrease in effective charge-carrier mobility across the same series, with the O-containing COF exhibiting the highest value of 0.19 ±0.02 cm 2 V −1 s −1 . Density functional theory (DFT) and time-dependent DFT calculations further revealed that valence-band dispersion originates from coupling between TTNTA- and linker-derived states and that the low-energy absorption involves linker-centered mixed excitations with progressively decreasing oscillator strength from O to Se. Collectively, these findings establish systematic structure–property relationships between acceptor-core chalcogen substitution and the photophysical and electronic properties of donor–acceptor COFs, providing mechanistic insights into their composition-dependent behavior and guidance for the design of future COF-based semiconductors.
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BibTeX
@misc{xue2026atomic,
title = {{Atomic Chalcogen Substitution Modulates Photophysical Properties and Electronic Structure in Donor–Acceptor Covalent Organic Frameworks}},
author = {Tianhao Xue and Laura Fuchs and Bembe C. Mackintosh and Mariia Ferree and Roman Guntermann and Shuo Sun and Markus Döblinger and Frédéric Laquai and Laura M. Herz and Frank Ortmann and Thomas Bein},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15009255/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009255/v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Atomic Chalcogen Substitution Modulates Photophysical Properties and Electronic Structure in Donor–Acceptor Covalent Organic Frameworks
AU - Tianhao Xue
AU - Laura Fuchs
AU - Bembe C. Mackintosh
AU - Mariia Ferree
AU - Roman Guntermann
AU - Shuo Sun
AU - Markus Döblinger
AU - Frédéric Laquai
AU - Laura M. Herz
AU - Frank Ortmann
AU - Thomas Bein
PY - 2026
DA - 2026/09/22
PB - ChemRxiv
DO - 10.26434/chemrxiv.15009255/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009255/v1
AB - While chalcogen substitution has recently emerged as a means for tuning the properties of covalent organic frameworks (COFs), its influence on the intrinsic photophysical and charge-transport properties of isoreticular donor–acceptor COFs remains largely unknown. Here, an isoreticular series of novel donor–acceptor COFs was constructed from a tetrathienonaphthalene-based (TTNTA) node and linear donor–acceptor–donor linkers containing oxygen (O), sulfur (S), or selenium (Se) within their acceptor cores. Highly crystalline COFs with identical topology and comparable structural order were obtained, while the synthesis of preferentially oriented thin films enabled direct comparison of chalcogen-dependent optoelectronic properties. Time-resolved photoluminescence measurements revealed progressively shorter emissive-state lifetimes from the O- to the S- and Se-containing COFs. Optical-pump terahertz-probe spectroscopy showed a parallel decrease in effective charge-carrier mobility across the same series, with the O-containing COF exhibiting the highest value of 0.19 ±0.02 cm 2 V −1 s −1 . Density functional theory (DFT) and time-dependent DFT calculations further revealed that valence-band dispersion originates from coupling between TTNTA- and linker-derived states and that the low-energy absorption involves linker-centered mixed excitations with progressively decreasing oscillator strength from O to Se. Collectively, these findings establish systematic structure–property relationships between acceptor-core chalcogen substitution and the photophysical and electronic properties of donor–acceptor COFs, providing mechanistic insights into their composition-dependent behavior and guidance for the design of future COF-based semiconductors.
ER -