Hydroxyquinolines with extended fluorophores: arrays for turn-on and ratiometric sensing of cations
作者:Manuel A. Palacios、Zhuo Wang、Victor A. Montes、Grigory V. Zyryanov、Bethany J. Hausch、Karolina Jursíková、Pavel Anzenbacher Jr.
DOI:10.1039/b705392d
日期:——
8-Hydroxyquinoline-based ligands with extended conjugated fluorophores were designed to provide turn-on and ratiometric signal output optimized for use in fluorescence-based sensor arrays, where the changes in blue and green channels of the RGB signal are used to distinguish between cationic analytes.
Red−Green−Blue Emission from Tris(5-aryl-8-quinolinolate)Al(III) Complexes
作者:Radek Pohl、Victor A. Montes、Joseph Shinar、Pavel Anzenbacher
DOI:10.1021/jo035602q
日期:2004.3.1
A simple yet effective strategy for synthesis of 5-aryl-8-quinolinolate-based electroluminophores with tunable emission wavelengths is presented. Two different pathways for the attachment of electron-donating or electron-withdrawing aryl groups to the 5-position of the quinolinolate ligand via Suzuki coupling were developed. A successful tuning in the emission color was achieved: the emission wavelength was found to correlate with the Hammett constant of the respective substituents, providing a powerful strategy for prediction of the optical properties of new electroluminophores.
Molecular-Wire Behavior of OLED Materials: Exciton Dynamics in Multichromophoric Alq<sub>3</sub>-Oligofluorene-Pt(II)porphyrin Triads
作者:Victor A. Montes、César Pérez-Bolívar、Neeraj Agarwal、Joseph Shinar、Pavel Anzenbacher
DOI:10.1021/ja064471i
日期:2006.9.1
Donor-bridge-acceptor triads consisting of the Alq3 complex, oligofluorene bridge, and PtII tetraphenylporphyrin (PtTPP) were synthesized. The triads were designed to study the energy level/distance-dependence in energy transfer both in a solution and in solid state. The materials show effective singlet transfer from the Alq3-fluorene fluorophore to the porphyrin, while the triplet energy transfer, owing to the shorter delocalization of triplet excitons, appears to take place via a triplet energy cascade. Using femtosecond transient spectroscopy, the rate of the singlet-singlet energy transfer was determined. The exponential dependence of the donor-acceptor distance and the respective energy transfer rates of 7.1 x 1010 to 1.0 x 109 s-1 with the attenuation factor â of 0.21 +/- 0.02 A-1 suggest that the energy transfer proceeds via a mixed incohererent wire/superexchange mechanism. In the OLEDs fabricated using the Alq3-oligofluorene-PtTPP triads with better triplet level alignment, the order of a magnitude increase in efficacy appears to be due to facile triplet energy transfer. The devices, where the triplet-triplet energy transfer is of paramount importance, showed high color purity emission (CIE X,Y: 0.706, 0.277), which is almost identical to the emission from thin films. Most importantly, we believe that the design principles demonstrated above are general and may be used to prepare OLED materials with enhanced quantum efficacy at lowered operational potentials, being crucial for improved lifespan of OLEDs.