Singlet and triplet to doublet energy transfer: improving organic light-emitting diodes with radicals.
Nature Publishing Group UK
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Li, F., Gillett, A., Gu, Q., Ding, J., Chen, Z., Hele, T. J., Myers, W. K., et al. (2022). Singlet and triplet to doublet energy transfer: improving organic light-emitting diodes with radicals.. Nat Commun, 13 (1) https://doi.org/10.1038/s41467-022-29759-7
Funder: Leverhulme Trust; doi: https://doi.org/10.13039/501100000275
Organic light-emitting diodes (OLEDs) must be engineered to circumvent the efficiency limit imposed by the 3:1 ratio of triplet to singlet exciton formation following electron-hole capture. Here we show the spin nature of luminescent radicals such as TTM-3PCz allows direct energy harvesting from both singlet and triplet excitons through energy transfer, with subsequent rapid and efficient light emission from the doublet excitons. This is demonstrated with a model Thermally-Activated Delayed Fluorescence (TADF) organic semiconductor, 4CzIPN, where reverse intersystem crossing from triplets is characteristically slow (50% emission by 1 µs). The radical:TADF combination shows much faster emission via the doublet channel (80% emission by 100 ns) than the comparable TADF-only system, and sustains higher electroluminescent efficiency with increasing current density than a radical-only device. By unlocking energy transfer channels between singlet, triplet and doublet excitons, further technology opportunities are enabled for optoelectronics using organic radicals.
Article, /639/624/1020/1091, /639/301/1019/1020/1091, /120, /140/125, /140/58, /128, article
Engineering and Physical Sciences Research Council (EP/M005143/1)
Engineering and Physical Sciences Research Council (EP/M01083X/1)
European Research Council (670405)
European Commission Horizon 2020 (H2020) ERC (101020167)
External DOI: https://doi.org/10.1038/s41467-022-29759-7
This record's URL: https://www.repository.cam.ac.uk/handle/1810/337275