Efficient charge transfer process in Coumarin 153–nanotubolar TiO2 hybrid system

Ricci, Pier Carlo; Pozzo, Anna Da; Palmas, Simonetta; Muscas, Fabio; Carbonaro, Carlo Maria

doi:10.1016/j.cplett.2012.02.024

Cited by 11 publications

(8 citation statements)

References 30 publications

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“…As expected the optical properties strongly change as a function of the terminal group [8], revealing a high stoke shift for the 1a compound and a higher efficiency for the 1d compound. Generally, the maximum absorption peak depend on the π π* transition from the ground HOMO and HOMO-1 state to the excited LUMO bands.…”

Section: Figurementioning

confidence: 89%

Synthesis and characterization of tunable coumarin- linked glasses as new class of organic/inorganic phosphors

Luridiana¹,

Pretta²,

Secci³

et al. 2014

AIP Conference Proceedings

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Abstract.It is well known that stilbene with a trans conformation is highly fluorescent. From the viewpoint of molecular structure, coumarins bear a carbon-carbon double bond which is fixed as trans conformation as in trans-stilbene through a lactone structure. This can help to avoid the trans-cis transformation of the double bond under ultraviolet (UV) irradiation as observed in stilbene compounds and results in strong fluorescence and high fluorescence quantum yield and photostability in most of coumarin derivatives. Herein we report some preliminary results about the synthesis and spectroscopic characterization of tunable coumarins and the development of a new linkage protocol for the obtainment of monolayer coumarin-covalently linked glasses. The resulting organic/inorganic coumarin/silica based Self-Assembled Monolayer (SMA) film is proposed as new phosphors for the substituting of critical raw materials, like rare earths, in photonics applications.

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Section: Figurementioning

confidence: 89%

Synthesis and characterization of tunable coumarin- linked glasses as new class of organic/inorganic phosphors

Luridiana¹,

Pretta²,

Secci³

et al. 2014

AIP Conference Proceedings

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“…A dye with lower bandgap energy would absorb light at lower frequencies, thus transferring electrons into the conductive band of ZnO. In this way much higher light utilizations are usually reached [1,7,10]. Below our main results aimed at solving this problem will be elucidated, which are based on coumarin-153.…”

Section: Resultsmentioning

confidence: 99%

“…The electron-donor group lowers significantly the S ππ* and T ππ* energies, while the electron-acceptor group shifts the peaks of optical fluorescence and absorption to longer wavelengths. Therefore the absorption peak of coumarin-153 is shifted towards 430 nm, while the same peak for coumarin is known to be located at 365 nm as [7].…”

Section: Introductionmentioning

confidence: 99%

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Photostability testing for coumarin-153 doped ZnO thin films prepared with spin-coating technique

Brankov¹,

Locharoenrat²

2016

Ukr. J. Phys. Opt.

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Abstract. The main aim behind the present study is solar cells of increased efficiency and low cost per unit of power generation, specifically dye-sensitized cells. Their first component is semiconducting ZnO commonly used to build photovoltaics, which absorbs sunlight in the ultraviolet region. The second component, the dye coumarin-153 that absorbs in a lower-energy spectral region, enhances the light harvesting. We study the optical absorbance and fluorescence for the combination of coumarin-153 with ZnO nanoparticles, which are prepared in sol-gel films formed using a simple spin-coating technique for creating a stable photovoltaic.

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“…The large coumarin family (with more than 1000 derivatives) includes naturally occurring dye molecules that belong to the flavonoid class of plant secondary metabolites. Thanks to their remarkable photophysical properties, coumarins find applications in many and different areas, ranging from photonics to photochemistry and photobiology. − Indeed, the coumarin unit (5,6-benzo-2-pyrone), found in many natural and synthetic drug molecules, displays strong absorption cross sections in the near-UV–green wavelength region and a large radiative quantum yield, making the coumarin compounds suitable as laser dyes, as efficient fluorescent labels and probes, or as sensitizers for solar energy collectors. ,− In addition, coumarin derivatives are known for their antioxidant, anticoagulant, antibacterial, and anti-HIV properties largely applied in biology, medicine, and agriculture (such as enzyme inhibitors, anticoagulant agents, , drugs with spasmolytic and anticancer activity, − sun-screening additives, and pesticides ,, ). The Hymecromone (7-hydroxy-4-methyl-coumarin, Scheme a), also known as umbelliferone or coumarin 4 (C4), is often regarded as the parent molecule of this family of heterocyclic compounds and has been largely investigated as the archetype for the photochemical and photophysical properties of the coumarin family.…”

Section: Introductionmentioning

confidence: 99%

Optical Characterization of PEG-Supported 7-Hydroxy-4-methyl-coumarin in Distilled Water Solution

Carbonaro¹,

Ricci²,

Casula³

et al. 2012

J. Phys. Chem. A

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The optical properties of 7-hydroxy-4-methyl coumarin immobilized on polyethylene glycol support and dissolved in distilled water solution are compared with the optical properties of the dye dissolved in ethanol and discussed on the basis of the formation of different chemical species of the dye molecule. The presence of the polymeric support affects both the absorption and emission features of the coumarin by changing the chemical equilibrium among the different species typically observed at the ground and excited states. The optical properties of synthesized PEG-supported coumarins are able to warrant biomedical applications in water-based environment and enable us to gain insight into the photophysical activity of coumarins; in particular, the steric hindrance of the polymeric support inhibits, as expected, the formation of the tautomeric form of the compound in the excited state, a further proof of the single-step neutral to tautomer reaction in coumarins.

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Efficient charge transfer process in Coumarin 153–nanotubolar TiO2 hybrid system

Cited by 11 publications

References 30 publications

Synthesis and characterization of tunable coumarin- linked glasses as new class of organic/inorganic phosphors

Synthesis and characterization of tunable coumarin- linked glasses as new class of organic/inorganic phosphors

Photostability testing for coumarin-153 doped ZnO thin films prepared with spin-coating technique

Optical Characterization of PEG-Supported 7-Hydroxy-4-methyl-coumarin in Distilled Water Solution

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