Near-IR phosphorescent metalloporphyrin as a photochemical upconversion sensitizer

Deng, Fan; Sommer, Jonathan R.; Myahkostupov, Mykhaylo; Schanze, Kirk S.; Castellano, Felix N.

doi:10.1039/c3cc44479a

Cited by 71 publications

(68 citation statements)

References 29 publications

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“…Therefore, the emission quenching in Pt-DPA can be ascribed to the exothermic TTET from the photosensitizer to the DPA acceptor, which is further strengthened by the transient absorption measurements. This finding is in accordance with typical TTA-UC examples 30,32,33 . Although there is an intramolecular TTET in Pt-DPA, neither phosphorescence nor fluorescence from DPA was observed at ambient temperature.…”

Section: Steady-state Absorption and Emission Propertiessupporting

confidence: 91%

“…The free-energy change involved in an electron transfer process from the triplet state of the photosensitizer to DPA is calculated to be positive, thus, the electron transfer can be excluded for the cause of the emission quenching in Pt-DPA. The slight difference of the upconverted fluorescence from that of DPA-OH is caused by the inner filter effect owing to the relatively high concentration of DPA-OH in the TTA-UC system, which is similar to that reported in literatures 30,31 . Therefore, the emission quenching in Pt-DPA can be ascribed to the exothermic TTET from the photosensitizer to the DPA acceptor, which is further strengthened by the transient absorption measurements.…”

Section: Steady-state Absorption and Emission Propertiessupporting

confidence: 87%

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Intramolecular triplet–triplet energy transfer enhanced triplet–triplet annihilation upconversion with a short-lived triplet state platinum(ii) terpyridyl acetylide photosensitizer

Zeng

Chen

et al. 2015

RSC Adv.

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A model of dendritic compound (Pt-DPA) with two Pt-complex photosensitizer chromophores and two 9,10diphenylanthracene (DPA) acceptor groups covalently attached to the periphery and the core of the poly(aryl ether) dendrimer of generation 1 was prepared. A triplet-triplet annihilation upconversion (TTA-UC) system (Pt-DPA/DPA-OH) was constructed in deaerated DMF by combining Pt-DPA with a dissociative acceptor (DPA-OH). Although the lifetime of the triplet state of Pt-complex is only 52 ns, the upconversion fluorescence from DPA (400 ~ 460 nm) in the Pt-DPA/DPA-OH system was observed with quantum yield of 0.22% upon selective excitation of the Pt-complex with a 473 nm laser, which is due to the efficient intramolecular triplet-triplet energy transfer (Φ TTET > 0.81) from the Pt-complex photosensitizer to the DPA acceptor within Pt-DPA. The acceptor covalently linked with the photosensitizer acts as an energy-relay to transfer the harvested energy to the dissociative acceptor which further undergoes the TTA process. The efficient intramolecular triplet-triplet energy transfer process between the photosensitizer and the acceptor plays an important role for the TTA-UC system building with a short-lived triplet state photosensitizer, which facilitates the production of the triplet state of the acceptor, thus advancing the TTA-UC process. This work presents a new strategy for construction of efficient TTA-UC systems utilizing short-lived triplet state photosensitizers.

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Section: Steady-state Absorption and Emission Propertiessupporting

confidence: 91%

Section: Steady-state Absorption and Emission Propertiessupporting

confidence: 87%

Intramolecular triplet–triplet energy transfer enhanced triplet–triplet annihilation upconversion with a short-lived triplet state platinum(ii) terpyridyl acetylide photosensitizer

Zeng

Chen

et al. 2015

RSC Adv.

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“…Along with the enhancement of power density, the slope gradually decreased to 1.8 and eventually became to 1.3 (nearly 1.0) upon 23.04 mW/cm 2 . It should be noted that the point of power density wherein the dependence of upconversion intensity on laser power density switching from quadratic to linear is very important to gain best upconversion quantum efficiency and strong TTA upconversion . In this aspect, it provided further decisive experimental evidence for strong TTA‐based upconversion of Ir–COOH/DPA system in this work.…”

Section: Main Textmentioning

confidence: 55%

Green to Blue Annihilated Upconversion from a Simple Iridium(III) Sensitizer with Carboxylic Group

et al. 2016

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A novel iridium(III) complex with carboxylic group (Bis[6‐(benzo[b]thiophen‐2‐yl)phenanthridine‐C3,N](4‐methyl‐4′‐carboxypropyl‐2,2′‐bipyridine)iridium(III)chloride, named Ir–COOH in this work) is investigated for the first time as a sensitizer in triplet‐triplet annihilation (TTA) upconversion studies. Without the aid of bulky incorporated light‐harvesting groups, this simple iridium(III) sensitizer has moderate absorbance in visible light regions (ϵ=7750 M−1cm−1 at 532 nm, ϵ is molar extinction coefficient). Under the assistant of 9,10‐diphenylanthracene (DPA) as a triplet acceptor, green to blue upconversion from Ir–COOH/DPA system is obviously visible under the naked eyes and the upconversion efficiency is 9.5 % in deaerated DMF.

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“…[17][18][19][20][21][22] The Qb and absorptions of porphyrin complexes locate in the green region and the lifetimes of their triplet states can last tens to hundreds of microseconds, which benefit the TTA-UC process.F urthermore, porphyrinoids with strong and broad absorption have also been appliedt oi mprovet he TTA-UC performance. [23][24][25][26] Developing and improving TTA-UC systemsb ased on porphyrin complexes with broad absorption bands of long wavelength and intense absorption coefficients is an attractive focus. Researchers have developed as eries of meso-meso-linked porphyrin complexes, which exhibit broad and enhanced absorption bands arisingf rom the excitonic interactions between constituent porphyrin units.…”

Section: Introductionmentioning

confidence: 99%

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

Xun

Zeng

Chen

et al. 2016

Chemistry A European J

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A series of directly meso-meso-linked Pd-porphyrin oligomers (PdDTP-M, PdDTP-D, and PdDTP-T) have been prepared. The absorption region and the light-harvesting ability of the Pd-porphyrin oligomers are broadened and enhanced by increasing the number of Pd-porphyrin units. Triplet-triplet annihilation upconversion (TTA-UC) systems were constructed by utilizing the Pd-porphyrin oligomers as the sensitizer and 9,10-diphenylanthracene (DPA) as the acceptor in deaerated toluene and green-to-blue photon upconversion was observed upon excitation with a 532 nm laser. The triplet-triplet annihilation upconversion quantum efficiencies were found to be 6.2 %, 10.5 %, and 1.6 % for the [PdDTP-M]/DPA, [PdDTP-D]/DPA, and [PdDTP-T]/DPA systems, respectively, under an excitation power density of 500 mW cm(-2) . The photophysical processes of the TTA-UC systems have been investigated in detail. The higher triplet-triplet annihilation upconversion quantum efficiency observed in the [PdDTP-D]/DPA system can be rationalized by the enhanced light-harvesting ability of PdDTP-D at 532 nm. Under the same experimental conditions, the [PdDTP-D]/DPA system produces more (3) DPA* than the other two TTA-UC systems, benefiting the triplet-triplet annihilation process. This work provides a useful way to develop efficient TTA-UC systems with broad spectral response by using Pd-porphyrin oligomers as sensitizers.

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Near-IR phosphorescent metalloporphyrin as a photochemical upconversion sensitizer

Cited by 71 publications

References 29 publications

Intramolecular triplet–triplet energy transfer enhanced triplet–triplet annihilation upconversion with a short-lived triplet state platinum(ii) terpyridyl acetylide photosensitizer

Intramolecular triplet–triplet energy transfer enhanced triplet–triplet annihilation upconversion with a short-lived triplet state platinum(ii) terpyridyl acetylide photosensitizer

Green to Blue Annihilated Upconversion from a Simple Iridium(III) Sensitizer with Carboxylic Group

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

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