Triplet-triplet annihilation photon upconversion from diphenylhexatriene and ring-substituted derivatives in solution

  • Phys Chem Chem Phys. 2022 May 18;24(19):11520-11526. doi: 10.1039/d1cp04784a.
Toshiko Mizokuro  1 ,  Kenji Kamada  2 ,  Yoriko Sonoda  1
Affiliations
  • 1. RIAEP, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan. [email protected].
  • 2. NMRI, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
PMID: 35416189 DOI: 10.1039/d1cp04784a
Abstract

We report that diphenylhexatriene (DPH) and its ring-substituted derivatives act as emitter molecules in triplet-triplet annihilation photon upconversion (TTA-UC). A palladium porphyrin derivative, meso-tetraphenyl-tetrabenzoporphine palladium complex (PdTPBP), which acts as a sensitiser in TTA-UC, and DPH derivatives were dissolved in tetrahydrofuran (THF). The solution showed blue-green to green UC emission under photoexcitation at 640 nm in a nitrogen atmosphere. The UC quantum efficiency (ηUC) values of the DPHs were estimated, with (E,E,E)-1,6-bis[4-(di-2-picolylamino)phenyl]hexa-1,3,5-triene (pico DPH) showing the highest. In addition, the quantum yields of triplet energy transfer (TET) and triplet-triplet annihilation (TTA), which are elementary processes in TTA-UC, were estimated, as well as the triplet lifetimes of each DPH derivative. The results indicate that the TTA process governs the value of ηUC.

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