Related Experiment Video
Updated: Sep 27, 2025

Integrating a Triplet-triplet Annihilation Up-conversion System to Enhance Dye-sensitized Solar Cell Response to Sub-bandgap Light
Published on: September 12, 2014
Triplet-triplet annihilation photon upconversion from diphenylhexatriene and ring-substituted derivatives in solution
Toshiko Mizokuro1, Kenji Kamada2, Yoriko Sonoda1
1RIAEP, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan. mizokuro-t@aist.go.jp.
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.
Related Concept Videos
Thermal and Photochemical Electrocyclic Reactions: Overview
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation
Aromatic Hydrocarbon Cations: Structural Overview
Removing one hydrogen from the intervening CH2 group...
Nucleophilic Aromatic Substitution: Elimination–Addition
Electrophilic Addition to Alkynes: Halogenation
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
Cycloaddition Reactions: MO Requirements for Photochemical Activation

![[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)