Approaching the Spin-Statistical Limit in Visible-to-Ultraviolet Photon Upconversion
Journal article, 2022

Triplet-triplet annihilation photon upconversion (TTA-UC) is a process in which triplet excitons combine to form emissive singlets and holds great promise in biological applications and for improving the spectral match in solar energy conversion. While high TTA-UC quantum yields have been reported for, for example, red-to-green TTA-UC systems, there are only a few examples of visible-to-ultraviolet (UV) transformations in which the quantum yield reaches 10%. In this study, we investigate the performance of six annihilators when paired with the sensitizer 2,3,5,6-tetra(9H-carbazol-9-yl)benzonitrile (4CzBN), a purely organic compound that exhibits thermally activated delayed fluorescence. We report a record-setting internal TTA-UC quantum yield (φUC,g) of 16.8% (out of a 50% maximum) for 1,4-bis((triisopropylsilyl)ethynyl)naphthalene, demonstrating the first example of a visible-to-UV TTA-UC system approaching the classical spin-statistical limit of 20%. Three other annihilators, of which 2,5-diphenylfuran has never been used for TTA-UC previously, also showed impressive performances with φUC,g above 12%. In addition, a new method to determine the rate constant of TTA is proposed, in which only time-resolved emission measurements are needed, circumventing the need for more challenging transient absorption measurements. The results reported herein represent an important step toward highly efficient visible-to-UV TTA-UC systems that hold great potential for driving high-energy photochemical reactions.

Author

Axel Olesund

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Jessica Johnsson

Student at Chalmers

Fredrik Edhborg

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Shima Ghasemi

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Kasper Moth-Poulsen

Catalan Institution for Research and Advanced Studies

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Institute of Material Science of Barcelona (ICMAB)

Bo Albinsson

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Journal of the American Chemical Society

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

Vol. 144 8 3706-3716

Unconventional Technology for Solar Electricity

Swedish Energy Agency (36436-2), 2017-01-17 -- 2020-12-31.

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.

Subject Categories

Atom and Molecular Physics and Optics

Other Physics Topics

Bioenergy

DOI

10.1021/jacs.1c13222

PubMed

35175751

More information

Latest update

6/13/2022