| Title |
The statistical probability factor in triplet mediated photon upconversion: a case study with perylene / |
| Authors |
Naimovičius, Lukas ; Radiunas, Edvinas ; Dapkevičius, Manvydas ; Bharmoria, Pankaj ; Moth-Poulsen, Kasper ; Kazlauskas, Karolis |
| DOI |
10.1039/d3tc03158f |
| Full Text |
|
| Is Part of |
Journal of materials chemistry C.. Cambridge : Royal society of chemistry. 2023, vol. 11, iss. 42, p. 14826-14832.. ISSN 2050-7526. eISSN 2050-7534 |
| Abstract [eng] |
Triplet–triplet annihilation photon upconversion (TTA-UC) is a process where two low-energy photons are converted into one higher-energy photon. A crucial component for an efficient upconversion process is the statistical probability factor ( f), defined as the probability of the formation of a high-energy singlet state upon coupling of two low-energy triplet states. Theoretically, f depends on the energy level distribution, molecular orientation, inter-triplet exchange coupling of triplet dyads, and spin-mixing of resulting spin states (singlet, triplet, and quintet). However, experimental values of f for acene-based annihilators have been subject to large variations due to many factors that have resulted in the reporting of different f values for the same molecule. In this work, we discuss these factors by studying perylene as a case study annihilator, for which by far the largest variation in f = 16 to 100% has been reported. We systematically investigated the TTA-UC of PdTPBP:perylene, as a sensitizer–annihilator pair and obtained the experimental f = 17.9 2.1% for perylene in THF solution. This limits the maximum TTA-UC quantum yield to 9.0% (out of 50%) for this annihilator. We found that such a low f value for perylene is largely governed by the energy-gap law where higher nonradiative losses due to the small energy gap between 2 T1 and T2 affect the probability of singlet formation. Interestingly, we found this observation true for other acene-based annihilators whose emission ranges from the UV to the yellow region, thus providing a blueprint for future design of efficient TTA-UC systems. |
| Published |
Cambridge : Royal society of chemistry |
| Type |
Journal article |
| Language |
English |
| Publication date |
2023 |
| CC license |
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