Diphenylanthracene Dimers for Triplet–Triplet Annihilation Photon Upconversion: Mechanistic Insights for Intramolecular Pathways and the Importance of Molecular Geometry
Journal article, 2021

Novel approaches to modify the spectral output of the sun have seen a surge in interest recently, with triplet–triplet annihilation driven photon upconversion (TTA-UC) gaining widespread recognition due to its ability to function under low-intensity, noncoherent light. Herein, four diphenylanthracene (DPA) dimers are investigated to explore how the structure of these dimers affects upconversion efficiency. Also, the mechanism responsible for intramolecular upconversion is elucidated. In particular, two models are compared using steady-state and time-resolved simulations of the TTA-UC emission intensities and kinetics. All dimers perform TTA-UC efficiently in the presence of the sensitizer platinum octaethylporphyrin. The meta-coupled dimer 1,3-DPA2 performs best yielding a 21.2% upconversion quantum yield (out of a 50% maximum), which is close to that of the reference monomer DPA (24.0%). Its superior performance compared to the other dimers is primarily ascribed to the longer triplet lifetime of this dimer (4.7 ms), thus reinforcing the importance of this parameter. Comparisons between simulations and experiments reveal that the double-sensitization mechanism is part of the mechanism of intramolecular upconversion and that this additional pathway could be of great significance under specific conditions. The results from this study can thus act as a guide not only in terms of annihilator design but also for the design of future solid-state systems where intramolecular exciton migration is anticipated to play a major role.


intramolecular TTA

photon upconversion

solar energy conversion


Axel Olesund

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Victor Gray

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Jerker Mårtensson

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Bo Albinsson

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Journal of the American Chemical Society

0002-7863 (ISSN) 1520-5126 (eISSN)

Vol. 143 15 5745-5754

Photon upconversion under diffusion-free conditions: Breaking the Shockley-Queisser limit for solar energy devices

Swedish Energy Agency (46526-1), 2019-01-01 -- 2023-12-31.

Driving Forces

Sustainable development

Areas of Advance

Nanoscience and Nanotechnology (SO 2010-2017, EI 2018-)

Subject Categories

Physical Chemistry

Chemical Sciences





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