Recent advances in instrumentation for absolute emission quantum yield measurements

Ishida, Hideyuki; Tobita, Seiji; Hasegawa, Yasuchika; Katoh, Ryuzi; Nozaki, Koichi

doi:10.1016/j.ccr.2010.04.006

Cited by 299 publications

(282 citation statements)

References 57 publications

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“…Ru(bpy) 3 2+ dissolved in aqueous solution exhibits a large nonradiative rate constant and a quantum yield of emission that is smaller than that observed for the photoacids dissolved in aqueous solution (ϕ em < 0.07 for Ru(bpy) 3 2+ and ϕ em ≈ 0.29 for the photoacid). 52 Notwithstanding, J ph values for cPFSA were observed to be orders-of-magnitude larger than for iPFSA-Ru, which implies that the observed photovoltaic action for cPFSA was not due to local heating caused by nonradiative decay of the excited-state photoacids or electron-transfer/energy-transfer to dissolved O 2 in the aqueous electrolyte.…”

Section: Journal Of the American Chemical Societymentioning

confidence: 94%

Observation of Photovoltaic Action from Photoacid-Modified Nafion Due to Light-Driven Ion Transport

et al. 2017

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Replacing passive ion-exchange membranes, like Nafion, with membranes that use light to drive ion transport would allow membranes in photoelectrochemical technologies to serve in an active role. Toward this, we modified perfluorosulfonic acid ionomer membranes with organic pyrenol-based photoacid dyes to sensitize the membranes to visible light and initiate proton transport. Covalent modification of the membranes was achieved by reacting Nafion sulfonyl fluoride poly-(perfluorosulfonyl fluoride) membranes with the photoacid 8-hydroxypyrene-1,3,6-tris(2-aminoethylsulfonamide). The modified membranes were strongly colored and maintained a high selectivity for cations over anions. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and ionexchange measurements together provided strong evidence of covalent bond formation between the photoacids and the polymer membranes. Visible-light illumination of the photoacid-modified membranes resulted in a maximum power-producing ionic photoresponse of ∼100 μA/cm 2 and ∼1 mV under 40 Suns equivalent excitation with 405 nm light. In comparison, membranes that did not contain photoacids and instead contained ionically associated Ru II −polypyridyl coordination compound dyes, which are not photoacids, exhibited little-to-no photoeffects (∼1 μA/cm 2 ). These disparate photocurrents, yet similar yields for nonradiative excited-state decay from the photoacids and the Ru II dyes, suggest temperature gradients were not likely the cause of the observed photovoltaic action from photoacid-modified membranes. Moreover, spectral response measurements supported that light absorption by the covalently bound photoacids was required in order to observe photoeffects. These results represent the first demonstration of photovoltaic action from an ion-exchange membrane and offer promise for supplementing the power demands of electrochemical processes with renewable sunlight-driven ion transport.

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Section: Journal Of the American Chemical Societymentioning

confidence: 94%

Observation of Photovoltaic Action from Photoacid-Modified Nafion Due to Light-Driven Ion Transport

et al. 2017

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“…p* dmphen ) to the ground state, as typically observed for iridium complexes. [40] The relative PL efficiency of the complex (l em,max = 522 nm) was calculated to be 0.92 in MeCN when Ru(bpy) 3 2 + was taken as a standard (F PL = 0.095 in MeCN [41] ). The emission lifetime of this complex at 522 nm in MeCN at room temperature was measured to be 293 ns, which is longer than that of (bt) 2 Ir(Hbpdc) (t = 99 ns) (Hbpdc = 2,2'-bipyridine-4,4'-dicarboxylate).…”

Section: Photophysical and Electrochemical Properties Of The Complexmentioning

confidence: 99%

Cyclometalated Iridium‐Complex‐Based Label‐Free Supersandwich Electrogenerated Chemiluminescence Biosensor for the Detection of Micro‐RNA

et al. 2017

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The synthesis and characterization of compounds as electrogenerated chemiluminescence (ECL) reagents are crucial in fundamental research for ECL biosensors. In this work, a new cyclometalated iridium(III) complex, [(bt) 2 Ir(dmphen)](PF 6 ), was synthesized by using 2-phenylbenzothiazole (bt) as the C^N main ligand and 5,6-dimethyl-1,10-phenanthroline (dmphen) as the N^N ancillary ligand. The photophysical, electrochemical, and ECL properties of this complex were extensively studied in acetonitrile solvent and aqueous solution. This complex displayed yellow-green photoluminescence with a maximum wavelength at 522 nm, a reversible one-electron oxidation wave at E 1/2 = + 1.51 V (vs. SCE), and a reversible one-electron reduction wave at À1.29 V (vs. SCE). Typically, in the annihilation process, the ECL efficiency of this complex was 12 times higher than that of Ru(bpy) 3 2 + . More importantly, a highly sensitive ECL method for the determination of micro-RNA at the subpicomolar level was developed on basis of employing this complex as an ECL intercalator and signal amplification by using the supersandwich model. Compared with Ru(phen) 3 Cl 2 and [(bt) 2 Ir(dcbpy)](PF 6 ), this complex showed a relatively low background and the highest increased ratio as an ECL intercalator in the developed system. The increased ECL intensity was directly proportional to the concentration of the micro-RNA in the range of 0.1 to 10 pM, with a detection limit of 13 fM. The developed method can effectively discriminate target micro-RNA122 from two-base mismatched micro-RNA122. This work demonstrates that this cyclometalated iridium(III) complex is an effective alternative intercalator for ECL determination of the micro-RNA. It is expected that this complex will be extended to design various analytical platforms for the detection of diverse analytes such as DNA/RNA, DNAzyme/target, and aptamer/targets.

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“…71 Furthermore, the luminescence lifetime was determined in both air-equilibrated (λexc = 440 nm; 189 ± 4 ns) and degassed (λexc = 440 nm; 1130 ± 28 ns) acetonitrile solutions. The results are comparable to those reported for similar Ru(II) polypyridyl complexes, indicating a phosphorescence-type emission.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization, and Biological Evaluation of New Ru(II) Polypyridyl Photosensitizers for Photodynamic Therapy

et al. 2014

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Two Ru(II) polypyridyl complexes, Ru(DIP)2(bdt) (1) and [Ru(dqpCO2Me)(ptpy)](2+) (2) (DIP = 4,7-diphenyl-1,10-phenanthroline, bdt = 1,2-benzenedithiolate, dqpCO2Me = 4-methylcarboxy-2,6-di(quinolin-8-yl)pyridine), ptpy = 4'-phenyl-2,2':6',2 -terpyridine) have been investigated as photosensitizers (PSs) for photodynamic therapy (PDT). In our experimental settings, the phototoxicity and phototoxic index (PI) of 2 (IC50(light): 25.3 M, 420 nm, 6.95 J/cm(2); PI >4) and particularly of 1 (IC50(light): 0.62 M, 420 nm, 6.95 J/cm(2); PI: 80) are considerably superior compared to the two clinically approved PSs porfimer sodium and 5-aminolevulinic acid. Cellular uptake and distribution of these complexes was investigated by confocal microscopy (1) and by inductively coupled plasma mass spectrometry (1 and 2). Their phototoxicity was also determined against the Gram-(+) Staphylococcus aureus and Gram-(-) Escherichia coli for potential antimicrobial PDT (aPDT) applications. Both complexes showed significant aPDT activity (420 nm, 8 J/cm(2)) against Gram-(+) (S. aureus; >6 log10 CFU reduction) and, for 2, also against Gram-(-) E. coli (>4 log10 CFU reduction). Two Ru(II) polypyridyl complexes, Ru(DIP)2(bdt) (1) and [Ru(dqpCO2Me)(ptpy)] 2+ (2) (DIP = 4,7-diphenyl-1,10-phenanthroline; bdt = 1,2-benzenedithiolate; dqpCO2Me = 4-methylcarboxy-2,6-di(quinolin-8-yl)pyridine); ptpy = 4'-phenyl-2,2':6',2''-terpyridine) have been investigated as photosensitizers (PSs) for photodynamic therapy (PDT). In our experimental settings, the phototoxicity and photo-index (PI) of 2 (IC50(light): 25.3 μM, 420 nm, 6.95 J/cm 2 ; PI: >4) and particularly of 1 (IC50(light): 0.62 μM, 420 nm, 6.95 J/cm 2 ; PI: 80) are considerably superior compared to the two clinically approved PSs porfimer sodium and 5-aminolevulinic. Cellular uptake and distribution of these complexes was investigated by confocal microscopy (1) and by inductively coupled plasma-mass spectrometry (1 and 2). Their phototoxicity was also determined against the Gram-(+) S. aureus and Gram-(−) E. coli for potential antimicrobial PDT (aPDT) applications. Both complexes showed significant aPDT activity (420 nm, 8 J/cm 2 ) against Gram-(+) (S. aureus; >6 log10 CFU reduction) and, for 2, also against Gram-(−) E. coli (>4 log10 CFU reduction). 3Introduction.

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Recent advances in instrumentation for absolute emission quantum yield measurements

Cited by 299 publications

References 57 publications

Observation of Photovoltaic Action from Photoacid-Modified Nafion Due to Light-Driven Ion Transport

Observation of Photovoltaic Action from Photoacid-Modified Nafion Due to Light-Driven Ion Transport

Cyclometalated Iridium‐Complex‐Based Label‐Free Supersandwich Electrogenerated Chemiluminescence Biosensor for the Detection of Micro‐RNA

Synthesis, Characterization, and Biological Evaluation of New Ru(II) Polypyridyl Photosensitizers for Photodynamic Therapy

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