Pd–Porphyrin Oligomers Sensitized for Green‐to‐Blue Photon Upconversion: The More the Better?

Xun, Zhiqing; Zeng, Yi; Chen, Jinping; Yu, Tianjun; Zhang, Xiaohui; Yang, Guoqiang; Li, Yang

doi:10.1002/chem.201504498

Cited by 26 publications

(20 citation statements)

References 49 publications

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“…Furthermore, the upconverted emission spectra were collected by using an integrating sphere coupled to a spectrometer with a liquid‐nitrogen‐cooled charge‐coupled device (CCD) upon excitation with different intensities of 640 nm laser and the double logarithmic plots of the upconversion emission intensity as a function of the incident light power are presented in Figure a. The intensity of upconverted green emission shows dependence on the incident power from quadratic to linear with increasing excitation laser power, which further indicates that the upconverted emission originates from TTA upconversion . Two linear regions fitted to slopes of 1.9 and 1.2 have been demonstrated, which correspond to the low‐ and high‐power density regimes, respectively.…”

Section: Resultsmentioning

confidence: 99%

Light‐Harvesting Organic Nanocrystals Capable of Photon Upconversion

Zeng

et al. 2017

ChemSusChem

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Harvesting and converting low energy photons into higher ones through upconversion have great potential in solar energy conversion. A light‐harvesting nanocrystal assembled from 9,10‐distyrylanthracene and palladium(II) meso‐tetraphenyltetrabenzoporphyrin as the acceptor and the sensitizer, respectively effects red‐to‐green upconversion under incoherent excitation of low power density. An upconversion quantum yield of 0.29±0.02 % is obtained upon excitation with 640 nm laser of 120 mW cm−2. The well‐organized packing of acceptor molecules with aggregation‐induced emission in the nanocrystals dramatically reduces the nonradiative decay of the excited acceptor, benefits the triplet–triplet annihilation (TTA) upconversion and guides the consequent upconverted emission. This work provides a straightforward strategy to develop light‐harvesting nanocrystals based on TTA upconversion, which is attractive for energy conversion and photonic applications.

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Section: Resultsmentioning

confidence: 99%

Light‐Harvesting Organic Nanocrystals Capable of Photon Upconversion

Zeng

et al. 2017

ChemSusChem

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“…Previous efforts to achieve and improve TTA-UC have been devoted to elongating the triplet-state lifetimes of the components, improving the light-absorption features of the sensitizers and increasing the energetic matching between the donor and the acceptor . A variety of photosensitizers with optimized photophysical properties, such as Pt–Pd(II) porphyrin complexes, ,, Ru(II), Pt(II), Ir(III), , Re(I), and Cu(I) complexes, and organic triplet sensitizers, have been employed for generating TTA-UC. The metal-coordinated sensitizers are the widest studied and have met significant success, affording UC quantum yields up to 20% .…”

Section: Introductionmentioning

confidence: 99%

Enhanced Triplet–Triplet Energy Transfer and Upconversion Fluorescence through Host–Guest Complexation

et al. 2016

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Perylene-tethered pillar[5]arenes and C-boron-dipyrromethene (BODIPY) dyads were synthesized acting as emitters and organic triplet photosensitizers, respectively, for the purpose of improving the efficiency of triplet-triplet annihilation upconversion (TTA-UC). The photophysical properties of the sensitizers (guests) and the emitters (hosts) were not greatly influenced by the chemical modifications except for a notable decrease in the fluorescence quantum yields of the perlyene emitters due to the high local concentration. The perylene-tethered pillar[5]arenes form stable 1:1 complexes with a nitrile-bearing C-BODIPY dyad, showing association constants as high as 4.0 × 10 M. Through host-guest complexation, the efficiencies of both triplet-triplet energy transfer and TTA were significantly enhanced, which overcompensated for the loss of the fluorescence quantum yield of the emitters (hosts). Thus, an improved TTA-UC efficiency of 3.2% was observed even at a diluted concentration of 6 × 10 M, demonstrating for the first time the effectiveness of the supramolecular motif for enhancing TTA-UC without varying the inherent photophysical properties of sensitizers and emitters.

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“…Resulting dyads have been applied, for example, as biomimetic models for photosynthetic light harvesting 2–4 and electron transfer arrays, 5 fluorescence imaging agents, 6 molecular wires, 1,7 molecules for information storage, 8 and triplet state photosensitizers. 9,12…”

Section: Introductionmentioning

confidence: 99%

Symmetrical and Nonsymmetrical Meso–Meso Directly Linked Hydroporphyrin Dyads: Synthesis and Photochemical Properties

et al. 2017

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A series of a rigid meso-meso directly linked chlorin-chlorin, chlorin-bacteriochlorin, and bacteriochlorin-bacteriochlorin dyads, including free bases as well as Zn(II), Pd(II), and Cu(II) complexes, has been synthesized, and their absorption, emission, singlet oxygen (O) photosensitization, and electronic properties have been examined. Marked bathochromic shifts of the long-wavelength Q absorption band and increase in fluorescence quantum yields in dyads, in comparison to the corresponding monomers, are observed. Nonsymmetrical dyads (except bacteriochlorin-bacteriochlorin) show two distinctive Q bands, corresponding to the absorption of each dyad component. A nearly quantitative S-S energy transfer between hydroporphyrins in dyads, leading to an almost exclusive emission of hydroporphyrin with a lower S energy, has been determined. Several symmetrical and all nonsymmetrical dyads exhibit a significant reduction in fluorescence quantum yields in solvents of high dielectric constants; this is attributed to the photoinduced electron transfer. The complexation of one macrocycle by Cu(II) or Pd(II) enhances intersystem crossing in the adjacent, free base dyad component, which is manifested by a significant reduction in fluorescence and increase in quantum yield of O photosensitization.

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Pd–Porphyrin Oligomers Sensitized for Green‐to‐Blue Photon Upconversion: The More the Better?

Cited by 26 publications

References 49 publications

Light‐Harvesting Organic Nanocrystals Capable of Photon Upconversion

Light‐Harvesting Organic Nanocrystals Capable of Photon Upconversion

Enhanced Triplet–Triplet Energy Transfer and Upconversion Fluorescence through Host–Guest Complexation

Symmetrical and Nonsymmetrical Meso–Meso Directly Linked Hydroporphyrin Dyads: Synthesis and Photochemical Properties

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