UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Generating Long-Lived Triplet Excited States in Narrow Bandgap Conjugated Polymers

Marin-Beloqui, Jose M; Congrave, Daniel G; Toolan, Daniel TW; Montanaro, Stephanie; Guo, Junjun; Wright, Iain A; Clarke, Tracey M; ... Dimitrov, Stoichko D; + view all (2023) Generating Long-Lived Triplet Excited States in Narrow Bandgap Conjugated Polymers. Journal of the American Chemical Society 10.1021/jacs.2c12008. (In press). Green open access

[thumbnail of jacs.2c12008.pdf]
Preview
Text
jacs.2c12008.pdf - Published Version

Download (2MB) | Preview

Abstract

Narrow bandgap conjugated polymers are a heavily studied class of organic semiconductors, but their excited states usually have a very short lifetime, limiting their scope for applications. One approach to overcome the short lifetime is to populate long-lived triplet states for which relaxation to the ground state is forbidden. However, the triplet lifetime of narrow bandgap polymer films is typically limited to a few microseconds. Here, we investigated the effect of film morphology on triplet dynamics in red-emitting conjugated polymers based on the classic benzodithiophene monomer unit with the solubilizing alkyl side chains C16 and C2C6 and then used Pd porphyrin sensitization as a further strategy to change the triplet dynamics. Using transient absorption spectroscopy, we demonstrated a 0.45 ms triplet lifetime for the more crystalline nonsensitized polymer C2C6, 2-3 orders of magnitude longer than typically reported, while the amorphous C16 had only a 5 μs lifetime. The increase is partly due to delaying bimolecular electron-hole recombination in the more crystalline C2C6, where a higher energy barrier for charge recombination is expected. A triplet lifetime of 0.4 ms was also achieved by covalently incorporating 5% of Pd porphyrin into the C16 polymer, which introduced extra energy transfer steps between the polymer and porphyrin that delayed triplet dynamics and increased the polymer triplet yield by 7.9 times. This work demonstrates two synthetic approaches to generate the longest-lived triplet excited states in narrow bandgap conjugated polymers, which is of necessity in a wide range of fields that range from organic electronics to sensors and bioapplications.

Type: Article
Title: Generating Long-Lived Triplet Excited States in Narrow Bandgap Conjugated Polymers
Location: United States
Open access status: An open access version is available from UCL Discovery
DOI: 10.1021/jacs.2c12008
Publisher version: https://doi.org/10.1021/jacs.2c12008
Language: English
Additional information: This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry
URI: https://discovery.ucl.ac.uk/id/eprint/10164583
Downloads since deposit
26Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item