14642-34-3Relevant articles and documents
To the homogeneity range of tris(8-hydroxyquinoline)gallium
Avetissov, I. Ch.,Akkuzina,Kozlova,Avetisov
, p. 930 - 936 (2018/02/19)
A new technique for the analysis of p8-Hq-T diagrams has been developed for the metal-organic phosphor tris(8-hydroxyquinoline)gallium. The detection of mono- and bivariant equilibria within the p8-Hq-T diagram was done using simultaneous measurements of the photoluminescence and reflection spectra of the condensed phase under controlled p8-Hq pressure and temperature. Using preparations with purity better 99.9988 wt%, the Si-Gaq3Sj-Gaq3V and Si-Gaq3LV equilibria were studied and the corresponding p8-Hq-T diagram was plotted in the 408-665 K temperature range. For the α-Gaq3, it was demonstrated that changing the synthesis conditions within the homogeneity range of the phase resulted in change in the cell volume, chemical activity and electrical properties of crystalline preparation and thin layers deposited due to it.
Vibrational spectra of the Ga(III) complexes with oxine and clioquinol
Wagner, Claudia C.,González-Baró, Ana C.,Baran, Enrique J.
, p. 1762 - 1765 (2011/10/03)
The FTIR and FT-Raman spectra of the gallium(III) complexes of 8-hydroxyquinoline (oxine) and 5-chloro-7-iodo-8-hydroxyquinoline (clioquinol), were recorded and briefly discussed by comparison with the spectra of the uncoordinated ligands and with some related species.
Effects of systematic methyl substitution of metal (III) tris(n-methyl-8-quinolinolato) chelates on material properties for optimum electroluminescence device performance
Sapochak,Padmaperuma,Washton,Endrino,Schmett,Marshall,Fogarty,Burrows,Forrest
, p. 6300 - 6307 (2007/10/03)
We relate the chemical structure of a series of methyl (Me) substituted group III metal tris(8-quinolinolato) chelates (nMeq3M: n = 0, 3, 4, 5; M = Al3+, Ga3+) to their photoluminescence (PL), electroluminescence, and thermal properties. Methylation of the 8-quinolinol ligand at the 3 or 4 position (pyridyl ring) results in a factor of 1.4 and 3.0 enhancement of PL quantum efficiency (OPL), respectively, whereas methylation at the 5 position (phenoxide ring) results in a factor of ～ 3.0 decrease in PL relative to the unsubstituted analogue. Electroluminescent quantum efficiencies of undoped organic light-emitting devices using the aluminum tris(8-quinolinolato) chelates are 1, 0.45, 1.4, and 0.80% for unsubstituted 5-, 4-, and 3-methyl-8-quinolinol ligands, respectively. Devices made with the latter two ligands have a higher operating voltage to generate the same current density. Similar trends were observed for methylation of gallium tris(8-quinolinolato) chelates. We relate these results to the thermal properties of the compounds measured by simultaneous differential scanning calorimetry and thermal gravimetric analysis. The C-4 methylated derivatives exhibit ～60 °C lower crystalline melting points than all other derivatives, indicating the weakest cohesive forces between molecules. Unlike Alq3, both the C-4 and C-5 methylated derivatives show no recrystallization of the glassy state below 500 °C and exhibit ～-20-25 °C higher glass transition temperatures. We infer that methylation of the 8-quinolinol ligand reduces intermolecular interactions and consequently impedes charge transport through the film.
Determination of interface dipole and band bending at the Ag/tris (8-hydroxyquinolinato) gallium organic Schottky contact by ultraviolet photoemission spectroscopy
Schlaf,Schroeder,Nelson,Parkinson,Merritt,Crisafulli,Murata,Kafafi
, p. 142 - 152 (2008/10/08)
A tris(8-hydroxyquinolinato) gallium (Gaq3) thin film was grown in several steps on a previously in situ evaporated Ag thin film. Ultraviolet photoemission spectroscopy (UPS) measurements carried out prior to growth and after each growth step allowed the determination of the alignment of the highest occupied molecular orbital (HOMO) relative to the Fermi level of the Ag substrate. The deposition of ultra-thin (submonolayer) initial Gaq3 films allowed us to distinguish between band bending and interface dipole related high binding energy cutoff (secondary cutoff) shifts, which is necessary to determine the interface dipole with high precision. In order to determine the band bending with high accuracy it was necessary to identify the HOMO position of the submonolayer Gaq3 films. This was accomplished by removing the Ag related emission background in the low coverage spectra using the Fermi edge intensity as a measure for the Ag related emission. Our results demonstrate that the interface dipole builds up during the growth of the first one or two monolayers during which the HOMO position remains constant. The offset between the HOMO cutoff (low binding energy cutoff of the UP spectra) and the Ag Fermi edge was determined to be 1.67 eV, while the interface dipole amounted to 0.69 eV. In order to find an estimate for the alignment of the lowest unoccupied molecular orbital (LUMO) relative to the Ag Fermi edge, the HOMO/LUMO gap (2.70 eV) of Gaq3 was determined by optical absorption measurements. The LUMO offset was estimated to be -1.04 eV.
Sub-picosecond fluorescence dynamics of organic light-emitting diode tris(8-hydroxyquinoline) metal complexes
Humbs, Werner,Van Veldhoven, Emile,Zhang, Hong,Glasbeek, Max
, p. 10 - 18 (2008/10/08)
For a few complexes belonging to a new class of organic light-emitting diodes (OLED), namely Al(III)- and Ga(III)-tris-8-hydroxyquinoline (Alq3 and Gaq3), femtosecond fluorescence up-conversion measurements are reported. The fluorescence decays contain picosecond components when the complexes are dissolved in liquid solution. The fast components are not found in the time-resolved fluorescence of the complexes doped in an inert host crystal. The results in liquid solution are characteristic of a dynamic Stokes shift due to the solvation in a ligand-localized excited state. Furthermore, from the temporal behavior of the total fluorescence intensity it is concluded that, concomitant with solvation, adiabatic electron transfer takes place.
