Thermally Activated Delayed Fluorescence Sensitization of Bis(phenylethynyl)benzenes for Visible‐to‐UV Upconversion
DOKPE
- Lardani, Davide ORCID Adolphe Merkle Institute, University of Fribourg
- Ronchi, Alessandra ORCID University of Milano‐Bicocca, Italy
- Hu, Xueqian ORCID Adolphe Merkle Institute, University of Fribourg
- Monguzzi, Angelo ORCID University of Milano‐Bicocca, Italy
- Weder, Christoph ORCID Adolphe Merkle Institute, University of Fribourg
- 2026
Published in:
- ChemPhotoChem. - Wiley. - 2026, vol. 10, no. 1
heavy-metal-free sensitizers
organic annihilators
thermally activated delayed fluorescence
triplet–triplet energy transfers
UV photons
English
Sensitized triplet–triplet annihilation can be utilized to upconvert low-intensity visible (Vis) light into ultraviolet (UV) light,
making it useful for applications powered by short-wavelength sunlight. However, dye systems for this wavelength range are
limited. Here, we report that Vis-to-UV upconversion (UC) is achieved with dye pairs that include the thermally activated delayed
fluorescence (TADF) luminophores 2,3,5,6-tetrakis(carbazol-9-yl)benzonitrile (4CzBN) or 2,4,5,6-tetrakis(9H-carbazol-9-yl) isophthalonitrile (4CzIPN) as sensitizer and bis(phenylethynyl)benzene (BPEB) or an alkoxylated BPEB derivative as emitter. The
photophysical characterization of degassed toluene solutions of the four possible combinations of these dyes reveals efficient
triplet energy transfer efficiencies exceeding 80%, upconverted UV emission centered at ca. 380 nm with an anti-Stokes shift
of up to 0.64 eV from the blue range of the optical spectrum, excitation threshold intensities as low as ca. 25 mW·cm−2
, and UC quantum yields up to 4.5%, depending on the dye combination. These results establish pairs of TADF sensitizers and
BPEB emitters as viable candidates for Vis-to-UV (UC), broadening the molecular design space for next-generation photonic
and solar-powered UV applications.
making it useful for applications powered by short-wavelength sunlight. However, dye systems for this wavelength range are
limited. Here, we report that Vis-to-UV upconversion (UC) is achieved with dye pairs that include the thermally activated delayed
fluorescence (TADF) luminophores 2,3,5,6-tetrakis(carbazol-9-yl)benzonitrile (4CzBN) or 2,4,5,6-tetrakis(9H-carbazol-9-yl) isophthalonitrile (4CzIPN) as sensitizer and bis(phenylethynyl)benzene (BPEB) or an alkoxylated BPEB derivative as emitter. The
photophysical characterization of degassed toluene solutions of the four possible combinations of these dyes reveals efficient
triplet energy transfer efficiencies exceeding 80%, upconverted UV emission centered at ca. 380 nm with an anti-Stokes shift
of up to 0.64 eV from the blue range of the optical spectrum, excitation threshold intensities as low as ca. 25 mW·cm−2
, and UC quantum yields up to 4.5%, depending on the dye combination. These results establish pairs of TADF sensitizers and
BPEB emitters as viable candidates for Vis-to-UV (UC), broadening the molecular design space for next-generation photonic
and solar-powered UV applications.
- Faculty
- Faculté des sciences et de médecine
- Department
- AMI - Chimie des polymères et matériaux
- Language
-
- English
- Classification
- Chemistry
- Other electronic version
- License
-
CC BY
- Open access status
- hybrid
- Identifiers
-
- DOI 10.1002/cptc.202500347
- ISSN 2367-0932
- Persistent URL
- https://folia.unifr.ch/unifr/documents/334511
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