Electronic properties of isolated Ga N As M clusters: photoionization-, photodissociation- and photoluminescence quantum yields

1997 ◽  
Vol 40 (1-4) ◽  
pp. 490-492 ◽  
Author(s):  
Rolf Schäfer ◽  
Jörg A. Becker
2012 ◽  
Vol 84 (4) ◽  
pp. 991-1004 ◽  
Author(s):  
James S. Klimavicz ◽  
Jared F. Mike ◽  
Achala Bhuwalka ◽  
Aimeé L. Tomlinson ◽  
Malika Jeffries-EL

A series of symmetrical D-π-A-π-D molecules comprised of benzo[1,2-d;4,5-d']bisoxazole (BBO) and various arylenevinylenes was synthesized via a Knoevenagel condensation of 2,6-dimethyl BBO and the corresponding aryl aldehydes. The resulting compounds had energy levels that were easily modulated and broad absorptions in the visible spectrum. They also demonstrated high fluorescence quantum yields in solution. The solvatochromism of several derivatives was examined in a number of solvents, and it was found that the emission of the triphenylamine derivative varied by almost 100 nm, depending on the polarity of the solvent. Collectively, these results indicate that the optical and electronic properties of benzobisoxazoles are readily tuned through the choice of aryl co-monomer.


2020 ◽  
Vol 16 ◽  
pp. 895-903 ◽  
Author(s):  
Liliia Moshniaha ◽  
Marika Żyła-Karwowska ◽  
Joanna Cybińska ◽  
Piotr J Chmielewski ◽  
Ludovic Favereau ◽  
...  

Boomerang-shaped bipyrroles containing donor–acceptor units were obtained through a tandem palladium-mediated reaction consisting of a cyclization step, involving double C–H bond activation, and a double α-oxygenation. The latter reaction can be partly suppressed for the least reactive systems, providing access to α-unsubstituted boomerangs for the first time. These “α-free” systems are highly efficient fluorophores, with emission quantum yields exceeding 80% in toluene. Preliminary measurements show that helicene-like boomerangs may be usable as circularly polarized luminescent materials.


2015 ◽  
Vol 13 (40) ◽  
pp. 10198-10204 ◽  
Author(s):  
L. N. Mataranga-Popa ◽  
I. Torje ◽  
T. Ghosh ◽  
M. J. Leitl ◽  
A. Späth ◽  
...  

Three flavins with extended aromatic systems were synthesized in moderate to good yields by condensation of the corresponding amines with violuric acid. The compounds are highly fluorescent, show quantum yields of up to 80% and redox mechanisms similar to riboflavin.


Author(s):  
J.M. Bonar ◽  
R. Hull ◽  
R. Malik ◽  
R. Ryan ◽  
J.F. Walker

In this study we have examined a series of strained heteropeitaxial GaAs/InGaAs/GaAs and InGaAs/GaAs structures, both on (001) GaAs substrates. These heterostructures are potentially very interesting from a device standpoint because of improved band gap properties (InAs has a much smaller band gap than GaAs so there is a large band offset at the InGaAs/GaAs interface), and because of the much higher mobility of InAs. However, there is a 7.2% lattice mismatch between InAs and GaAs, so an InxGa1-xAs layer in a GaAs structure with even relatively low x will have a large amount of strain, and misfit dislocations are expected to form above some critical thickness. We attempt here to correlate the effect of misfit dislocations on the electronic properties of this material.The samples we examined consisted of 200Å InxGa1-xAs layered in a hetero-junction bipolar transistor (HBT) structure (InxGa1-xAs on top of a (001) GaAs buffer, followed by more GaAs, then a layer of AlGaAs and a GaAs cap), and a series consisting of a 200Å layer of InxGa1-xAs on a (001) GaAs substrate.


2002 ◽  
Vol 21 (2) ◽  
pp. 91-95 ◽  
Author(s):  
E. Ozturk ◽  
H. Sari ◽  
Y. Ergun ◽  
I. Sokmen

1988 ◽  
Vol 49 (4) ◽  
pp. 667-673 ◽  
Author(s):  
S. Söderholm ◽  
J. Hellberg ◽  
G. Ahlgren ◽  
M. Krebs ◽  
J.U. von Schütz ◽  
...  

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