Triplet-triplet annihilation upconversion (TTA-UC) has considerable potential for emerging applications in bioimaging, optogenetics, photoredox catalysis, solar energy harvesting, etc. Fluoroboron dipyrrole (Bodipy) dyes are an essential type of annihilator in TTA-UC. However, conventional Bodipy dyes generally have large molar extinction coefficients and small Stokes shifts (<20 nm), subjecting them to severe internal filtration effects at high concentrations, and resulting in low upconversion quantum efficiency of TTA-UC systems using Bodipy dyes as annihilators. In this study, a Bodipy dimer (B-2) with large Stokes shifts was synthesized using the strategy of dimerization of an already reported Bodipy annihilator (B-1). Photophysical characterization and theoretical chemical analysis showed that both B-1 and B-2 can couple with the red light-activated photosensitizer PdTPBP to fulfill TTA-UC; however, the higher fluorescence quantum yield of B-2 resulted in a higher upconversion efficiency () for PdTPBP/B-2 (10.7%) than for PdTPBP/B-1 (4.0%). This study proposes a new strategy to expand Bodipy Stokes shifts and improve TTA-UC performance, which can facilitate the application of TTA-UC in photonics and biophotonics.
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http://dx.doi.org/10.3390/molecules28145474 | DOI Listing |
Chemistry
January 2025
Shandong University, School of Chemistry and Chemical Engineering, 27 Shanda Nan Road, 250100, Jinan, CHINA.
Photophysical properties of condensed systems generally originate from collective contributions of all components in their stochastically fluctuated structures and are strongly influenced under strain of chromophores. To precisely identify how the stochastically fluctuated monomers synergistically manipulate the properties, we propose a statistic strategy over sufficient ab initio molecular dynamics (AIMD) samplings and for the first time uncover that synergistic oscillatory twisting (SOT) of neighboring under-strain monomers manipulates the bifunction of rubrene crystal. The under-strain trunk SOT can regulate both singlet fission (SF) and triplet-triplet annihilation (TTA), enabling their coexistence and dominance switching by dynamically modulating the matching of excitation energies.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Institute of Nanoscience and Engineering, Henan University, Kaifeng, Henan 475004, China.
ACS Appl Opt Mater
December 2024
Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield S1 3JD, U.K.
Triplet excited states in organic semiconductors are usually optically dark and long-lived as they have a spin-forbidden transition to the singlet ground state and therefore hinder processes in light-harvesting applications. Also, triplets often cause damage to the system as they can sensitize the formation of reactive singlet oxygen. Despite these unfavorable characteristics, there exist mechanisms through which we can utilize triplet states, and that constitutes the scope of this review.
View Article and Find Full Text PDFChimia (Aarau)
December 2024
Dept. of Chemistry, Dept. of Physics and Astronomy, Dept. of Materials Science and Nanoengineering, Rice Advanced Materials Institute, Rice University, Houston, Texas 77005, USA.
Photon interconversion promises to alleviate thermalization losses for high energy photons and facilitates utilization of sub-bandgap photons - effectively enabling the optimal use of the entire solar spectrum. However, for solid-state device applications, the impact of intermolecular interactions on the energetic landscape underlying singlet fission and triplet-triplet annihilation upconversion cannot be neglected. In the following, the implications of molecular arrangement, intermolecular coupling strength and molecular orientation on the respective processes of solid-state singlet fission and triplet-triplet annihilation are discussed.
View Article and Find Full Text PDFSci Rep
December 2024
Semiconductor Physics, Institute of Physics, Chemnitz University of Technology, 09126, Chemnitz, Germany.
Magnetic field effects (MFEs) in thermally activated delayed fluorescence (TADF) materials have been shown to influence the reverse intersystem crossing (RISC) and to impact on electroluminescence (EL) and conductivity. Here, we present a novel model combining Cole-Cole and Lorentzian functions to describe low and high magnetic field effects originating from hyperfine coupling, the Δg mechanism, and triplet processes. We applied this approach to organic light-emitting devices of third generation based on tris(4-carbazoyl-9-ylphenyl)amine (TCTA) and 2,2',2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi), exhibiting blue emission, to unravel their loss mechanisms.
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