The origin of luminescence blueshifts in Alq3 composites

Baldacchini, G.; Chiacchiaretta, Piero; Reisfeld, R.; Zigansky, E.

doi:10.1016/j.jlumin.2009.04.036

Cited by 24 publications

(20 citation statements)

References 18 publications

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“…Unlike the case of Mgq 2 , the PL peak wavelength of Znq 2 depends on solvent strongly. Baldacchini et al found that PL peak wavelength of Alq 3 changes when Alq 3 molecules are trapped in different sol-gel matrixes, and suggested presence of interaction of Alq 3 with neighboring molecules [18]. Such a solid solvation effect is confirmed to be applicable to the case of Znq 2 molecule in solutions.…”

Section: Resultsmentioning

confidence: 91%

Photoluminescence of bis(8-hydroxyquinoline) zinc (Znq2) and magnesium (Mgq2)

Tsuboi

Nakai

Torii³

2012

Open Physics

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Absorption and photoluminescence (PL) spectra, PL quantum efficiency, and PL lifetime have been investigated on bis(8-hydroxyquinoline) zinc (Znq2) and magnesium (Mgq2) in solutions and powder. Znq2 and Mgq2 have the lowest-energy absorption band at 376 and 396 nm in acetonitrile solution, respectively, and emission band with peak at 555 and 480 nm. The PL quantum efficiency is 0.03 and 0.45 for Znq2 and Mgq2 in the solution, respectively, while 0.45 and 0.36 in powder. Unlike the case of powders, two PL lifetimes are obtained in solutions. The longer lifetime is attributed to molecule having interaction with its neighboring molecule, while the shorter one to the isolated single molecule.

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Section: Resultsmentioning

confidence: 91%

Photoluminescence of bis(8-hydroxyquinoline) zinc (Znq2) and magnesium (Mgq2)

Tsuboi

Nakai

Torii³

2012

Open Physics

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“…In addition to the investigation of nanopore-entrapped Alq 3 species, various studies has been conducted for other porous systems such as porous glasses [ 28 ], sol-gel silica and zirconia materials [ 29 ], and mesoporous silica [ 30 , 31 ], which also reported blueshifts of the absorption and fluorescence peaks. In this study, we discuss the related results, containing two fluorescence peaks [ 30 , 31 ].…”

Section: Discussionmentioning

confidence: 99%

Formation and Entrapment of Tris(8-hydroxyquinoline)aluminum from 8-Hydroxyquinoline in Anodic Porous Alumina

Yamaguchi

Matsui

2016

Materials

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The formation and entrapment of tris(8-hydroxyquinoline)aluminum (Alq3) molecules on the surface of anodic porous alumina (APA) immersed in an ethanol solution of 8-hydroxyquinoline (HQ) were investigated by absorption, fluorescence, and Raman spectroscopies. The effects of the selected APA preparation conditions (galvanostatic or potentiostatic anodization method, anodizing current and voltage values, one- or two-step anodizing process, and sulfuric acid electrolyte concentration) on the adsorption and desorption of Alq3 species were examined. Among the listed parameters, sulfuric acid concentration was the most important factor in determining the Alq3 adsorption characteristics. The Alq3 content measured after desorption under galvanostatic conditions was 2.5 times larger than that obtained under potentiostatic ones, regardless of the adsorbed quantities. The obtained results suggest the existence of at least two types of adsorption sites on the APA surface characterized by different magnitudes of the Alq3 bonding strength. The related fluorescence spectra contained two peaks at wavelengths of 480 and 505 nm, which could be attributed to isolated Alq3 species inside nanovoids and aggregated Alq3 clusters in the pores of APA, respectively. The former species were attached to the adsorption sites with higher binding energies, whereas the latter ones were bound to the APA surface more weakly. Similar results were obtained for the Alq3 species formed from the HQ solution, which quantitatively exceeded the number of the Alq3 species adsorbed from the Alq3 solution. Alq3 molecules were formed in the HQ solution during the reaction of HQ molecules with the Al3+ ions in the oxide dissolution zone near the oxide/electrolyte interface through the cracks and the Al3+ ions adsorbed on surface of pore and cracks. In addition, it was suggested that HQ molecules could penetrate the nanovoids more easily than Alq3 species because of their smaller sizes, which resulted in higher magnitudes of the adsorption.

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“…The Alq3 thin film has an emission maximum at 510 nm when excited at 257 nm 28 . This emission of Alq3 is due to the relaxation of an excited electron from the S 1 ‐S 0 level localized on the a‐quinolate ligand 37,38 . The introduction of the Alq3 into the PMMA results in change of PL spectra.…”

Section: Resultsmentioning

confidence: 99%

The study of optical and photodielectric properties of polymethyl methacrylate and tris‐(8‐hydroxy‐quinoline) aluminum (Alq3) composites

Vuković

Škipina

Maletić

et al. 2021

J of Applied Polymer Sci

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Polymer composite films of tris‐(8‐hydroxy‐quinoline) aluminum (Alq3) and polymethyl methacrylate (PMMA) at two different concentrations were investigated. Dielectric properties of the samples were measured in broad frequency range and results show an increase in specific conductance and susceptance by adding Alq3 in PMMA. Changes in dielectric spectra caused by irradiation of the samples with LED lamps at different wavelengths were also recorded. The samples were examined by UV–Vis and Fourier transform infrared spectroscopy. The interaction between Alq3 and the polymer matrix was observed in the photoluminescence spectroscopy spectra. The doping of the PMMA with different concentrations of the Alq3 leads to the unique photodielectric properties of the resulting composite, and that is the main result of this study. Due to its interesting optical and photodielectric properties, PMMA/Alq3 film may find application in solar cells and optoelectronics.

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The origin of luminescence blueshifts in Alq3 composites

Cited by 24 publications

References 18 publications

Photoluminescence of bis(8-hydroxyquinoline) zinc (Znq2) and magnesium (Mgq2)

Photoluminescence of bis(8-hydroxyquinoline) zinc (Znq2) and magnesium (Mgq2)

Formation and Entrapment of Tris(8-hydroxyquinoline)aluminum from 8-Hydroxyquinoline in Anodic Porous Alumina

The study of optical and photodielectric properties of polymethyl methacrylate and tris‐(8‐hydroxy‐quinoline) aluminum (Alq3) composites

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