Highly efficient photochemical upconversion in a quasi-solid organogel

Sripathy, Kabilan; MacQueen, Rowan W.; Peterson, James L.; Cheng, Yuen Yap; Dvořák, Miroslav; McCamey, Dane R.; Treat, Neil D.; Stingelin, Natalie; Schmidt, Timothy W.

doi:10.1039/c4tc02584a

Cited by 74 publications

(81 citation statements)

References 50 publications

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“…It was shown that the upconverted fluorescence intensity was highly dependent on the temperature and decreased dramatically below the glass transition temperature ( T g ) of the polymer . This result suggested that translational and rotational mobility of the chromophores is essential for efficient upconversion in solid materials with low chromophore content, as the influence on the various energy transfer steps that are involved in the TTA‐UC process is significant . It was later hypothesized that an increase of the UC chromophore concentrations in the matrix could change this situation by way of enabling energy transfer on account of small intermolecular distances and, thus, increase the efficiency of TTA‐UC process in the solid state .…”

Section: Introductionmentioning

confidence: 99%

Glassy poly(methacrylate) terpolymers with covalently attached emitters and sensitizers for low-power light upconversion

Lee

Thévenaz

Weder

et al. 2015

J. Polym. Sci. Part A: Polym. Chem.

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Low‐power light upconversion by triplet–triplet annihilation (TTA‐UC) was only recently demonstrated in glassy polymers and the upconversion efficiency in these materials is typically much lower than in solution. As aggregation of the chromophores was thought to be the culprit, we here report the covalent tethering of a suitable chromophore pair to a polymeric backbone. The new materials were based on the sensitizer‐bearing monomer palladium meso‐phenoxy‐tris(heptyl)porphyrin‐ethylmethacrylate (PdmPH3PMA), which was copolymerized with a diphenylanthrancene methacrylate (DPAMA), as the emitter‐bearing monomer, and methyl methacrylate (MMA) as an optically inert comonomer. The DPA content was kept within a narrow range of 30–37 wt %, while the PdmPH3PMA content was varied between 0.73 and 0.012 wt %. To explore additional compositions, blends of a high‐porphyrin‐content terpolymer with a DPAMA‐MMA copolymer were also prepared. All of the materials studied were processed into thin films by solution‐casting and displayed blue TTA‐UC emission. The UC emission intensity was found to strongly depend on the composition and the underlying effects were investigated through a systematic study. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1629–1639

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Section: Introductionmentioning

confidence: 99%

Glassy poly(methacrylate) terpolymers with covalently attached emitters and sensitizers for low-power light upconversion

Lee

Thévenaz

Weder

et al. 2015

J. Polym. Sci. Part A: Polym. Chem.

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“…Standard spin statistics predict an efficiency of 1/9 for TTA, but usually the efficiency of TTA is higher because the high-energy quintet states are not accessible. Φ TTA is 0.52 for DPA 40,41 and 0.33 for rubrene. 42 Third, molecules with high PL QYs meet the requirements for sensitizers, such as the PL QYs of 0.90 for DPA 43,44 and 0.98 for rubrene.…”

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confidence: 99%

Designing Transmitter Ligands That Mediate Energy Transfer between Semiconductor Nanocrystals and Molecules

2017

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Molecular control of energy transfer is an attractive proposition because it allows chemists to synthetically tweak various kinetic and thermodynamic factors. In this Perspective, we examine energy transfer between semiconductor nanocrystals (NCs) and π-conjugated molecules, focusing on the transmitter ligand at the organic−inorganic interface. Efficient transfer of triplet excitons across this interface allows photons to be directed for effective use of the entire solar spectrum. For example, a photon upconversion system composed of semiconductor NCs as sensitizers, bound organic ligands as transmitters, and molecular annihilators has the advantage of large, tunable absorption cross sections across the visible and near-infrared wavelengths. This may allow the near-infrared photons to be harnessed for photovoltaics and photocatalysis. Here we summarize the progress in this recently reported hybrid upconversion platform and point out the challenges. Since triplet energy transfer (TET) from NC donors to molecular transmitters is one of the bottlenecks, emphasis is on the design of transmitters in terms of molecular energetics, photophysics, binding affinity, stability, and energy offsets with respect to the NC donor. Increasing the efficiency of TET in this hybrid platform will increase both the up-and down-conversion quantum yields, potentially exceeding the Shockley−Queisser limit for photovoltaics and photocatalysis.

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“…This gel Φ UC >0.6 and 14% under ambient and oxygen‐free conditions, respectively. Schmidt and co‐workers also reported UC in a supramolecular tetralin organogel made of 1,3:2,4‐bis(3,4‐dimethylbenzylidene) sorbitol (DMDBS) and containing the UC pair palladium tetraphenylporfirin and DPA . In this case, identical TTA‐UC efficiency in the gel sample and in a comparable liquid composition was observed (Φ TTA = 0.07), with the advantage of better processability for the former in terms of potential device applications.…”

Section: Photon Upconversionmentioning

confidence: 86%

Unreactive Gel Networks as Versatile Confined Spaces for Enhanced Photoinduced Processes

Häring

Abramov

Díaz

2017

Macromolecular Symposia

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Summary Gel materials have been recognized as promising confined media to enhance photoinduced reactions of reactants that are physically embedded in the gel network. In particular, stimuli‐responsive supramolecular self‐assembled gels that are unreactive to light irradiation constitute versatile materials to enhance both unimolecular and bimolecular photoinduced processes (in comparison to those carried out in solution) such as dimerization, isomerization and redox reactions, including multistep mechanisms.

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Highly efficient photochemical upconversion in a quasi-solid organogel

Abstract: Photochemical upconversion in a quasi-solid gel proceeds with an identical efficiency to an otherwise identical liquid composition.

Cited by 74 publications

References 50 publications

Glassy poly(methacrylate) terpolymers with covalently attached emitters and sensitizers for low-power light upconversion

Glassy poly(methacrylate) terpolymers with covalently attached emitters and sensitizers for low-power light upconversion

Designing Transmitter Ligands That Mediate Energy Transfer between Semiconductor Nanocrystals and Molecules

Unreactive Gel Networks as Versatile Confined Spaces for Enhanced Photoinduced Processes

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