Electronic structure and energy gaps evaluation of perovskite manganite single crystals using XES and XAS spectroscopy

2021 ◽  
pp. 147084
Author(s):  
Mahmoud Abu-Samak ◽  
Shalendra Kumar ◽  
Rezq Naji Aljawfi ◽  
Mohamed A. Swillam
Keyword(s):  
Electronic Structure ◽  
Single Crystals ◽  
Perovskite Manganite ◽  
Energy Gaps

Light-Emitting Diodes Based on Conjugated Polymers: Control of Colour and Efficiency

1992 ◽  
Vol 247 ◽  
Author(s):  
Paul L. Burn ◽  
A. B. Holmes ◽  
A. Kraft ◽  
A. R. Brown ◽  
D. D. C. Bradley ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Conjugated Polymers ◽  
Light Emitting Diodes ◽  
Fold Increase ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Metal Contacts ◽  
Light Emitting ◽  
Lithographic Patterning ◽  
Energy Gaps

ABSTRACTStudies of the effect of different electrode combinations on the device characteristics of simple three layer light-emitting diodes (LEDs) prepared with poly(ρ-phenylenevinylene) (PPV) as the emissive layer sandwiched between two metal contacts have shown that it is generally more difficult to inject electrons than holes. In order to improve the efficiency of such devices it is, therefore, necessary to develop methods to enhance the injection of electrons and we illustrate here one example where we have successfully achieved this by the introduction of a further, electron transport, layer. The result is an eight fold increase in efficiency over our best three layer PPV devices. The efficiency is also dependent on the details of the polymer electronic structure and using a family of copolymers we have been able to produce enhancements in efficiency to values of up to 30 times that of the corresponding PPV devices. Variations in the polymer electronic structure also affect the colour of emission and the same family of copolymers allow control of emission colour from blue/green to orange/red. Supramolecular control of the copolymer electronic structure can be achieved by lithographic patterning and we show that it is possible to produce regions within a single polymer film that possess different π-π* energy gaps.

Electronic structure of bismuth ferrite and hematite single crystals: X-ray photoelectron study and calculation

2011 ◽  
Vol 53 (1) ◽  
pp. 41-47 ◽  
Author(s):  
A. T. Kozakov ◽  
K. A. Guglev ◽  
V. V. Ilyasov ◽  
I. V. Ershov ◽  
A. V. Nikol’skii ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Single Crystals ◽  
Bismuth Ferrite ◽  
X Ray ◽  
Photoelectron Study

Optical constants and electronic structure of LaB6, EuB6 and SmB6 single crystals prepared by the solution method☆

1981 ◽  
Vol 82 ◽  
pp. 291-296 ◽  
Author(s):  
A SHELYKH ◽  
K SIDORIN ◽  
M KARIN ◽  
V BOBRIKOV ◽  
M KORSUKOVA ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Single Crystals ◽  
Optical Constants ◽  
Solution Method

Spectroscopic studies on plastocyanin single crystals: a detailed electronic structure determination of the blue copper active site

1981 ◽  
Vol 103 (15) ◽  
pp. 4382-4388 ◽  
Author(s):  
K. W. Penfield ◽  
R. R. Gay ◽  
R. S. Himmelwright ◽  
N. C. Eickman ◽  
V. A. Norris ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Single Crystals ◽  
Structure Determination ◽  
Active Site ◽  
Spectroscopic Studies ◽  
Blue Copper

POSSIBLE EVIDENCE FOR A VALENCE BAND SATELLITE IN PHOTOEMISSION SPECTRA FROM Sc(0001)

1994 ◽  
Vol 01 (04) ◽  
pp. 649-653 ◽  
Author(s):  
A.J. PATCHETT ◽  
S.S. DHESI ◽  
R.I.R. BLYTH ◽  
S.D. BARRETT
Keyword(s):  
Electronic Structure ◽  
Rare Earth ◽  
Binding Energy ◽  
Single Crystals ◽  
Valence Band ◽  
Ground State ◽  
Rare Earth Metals ◽  
Final State ◽  
Bulk Single Crystals ◽  
The Creation

An intense photoemission feature is observed at a binding energy of ~10 eV in the UV photoemission spectra from the (0001) surfaces of bulk single crystals of rare-earth metals. This emission cannot be explained in terms of ground state electronic structure and we have been unable to attribute its existence to the presence of contamination of the surface. We present some evidence that may indicate its origin lies in the creation, by the photoemission process, of a metastable two-hole final state.

Surface Electronic Structure of Hybrid Organo Lead Bromide Perovskite Single Crystals

2016 ◽  
Vol 120 (38) ◽  
pp. 21710-21715 ◽  
Author(s):  
Takashi Komesu ◽  
Xin Huang ◽  
Tula R. Paudel ◽  
Yaroslav B. Losovyj ◽  
Xin Zhang ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Single Crystals ◽  
Surface Electronic Structure ◽  
Lead Bromide

scholarly journals Effect of antiferromagnetic order on topological electronic structure in Eu-substituted Bi2Se3 single crystals

APL Materials ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 111108
Author(s):  
Soo-Whan Kim ◽  
Hoil Kim ◽  
Jeong-Kyu Kim ◽  
Woo-Suk Noh ◽  
Jinsu Kim ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Single Crystals ◽  
Antiferromagnetic Order

Meso-alkynyl corroles and their cobalt(III), manganese(III) and gallium(III) complexes

2020 ◽  
Vol 24 (05n07) ◽  
pp. 737-749
Author(s):  
Michael Haas ◽  
Sabrina Gonglach ◽  
Wolfgang Schöfberger
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Theoretical Study ◽  
Lumo Energy ◽  
Functional Theory ◽  
Energy Gaps ◽  
Peak Broadening ◽  
Homo And Lumo ◽  
Homo Lumo

We report routes towards synthesis of novel [Formula: see text]-conjugated freebase cobalt, copper, gallium and manganese meso-alkynylcorroles. UV-vis spectra show that extensive peak broadening, red shifts, and changes in the oscillator strength of absorptions increase with the extension of [Formula: see text]-conjugation. Using density functional theory (DFT), we have carried out a first theoretical study of the electronic structure of these metallocorroles. Decreased energy gaps of about 0.3–0.4 eV between the HOMO and LUMO orbitals compared to the corresponding copper, gallium and manganese meso-5,10,15 triphenylcorrole are observed. In all cases, the HOMO energies are nearly unperturbed as the [Formula: see text]-conjugation is expanded. The contraction of the HOMO–LUMO energy gaps is attributed to the lowered LUMO energies.

scholarly journals Inhomogeneity and Segregation Effect in the Surface Layer of Fe-Doped SrTiO3 Single Crystals

Crystals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 33 ◽  
Author(s):  
Marcin Wojtyniak ◽  
Katarzyna Balin ◽  
Jacek Szade ◽  
Krzysztof Szot
Keyword(s):  
Electronic Structure ◽  
Surface Layer ◽  
Single Crystals ◽  
Resistive Switching ◽  
Special Focus ◽  
Fe Doping ◽  
Reducing Conditions ◽  
Switching Phenomenon ◽  
Segregation Effect ◽  
Crystal And Electronic Structure

The effect of Fe doping on SrTiO3 single crystals was investigated in terms of crystal and electronic structure over a wide temperature range in both oxidizing and reducing conditions. The electrical properties were thoroughly studied with a special focus on the resistive switching phenomenon. Contrary to the undoped SrTiO3 crystals, where isolated filaments are responsible for resistive switching, the iron-doped crystals showed stripe-like conducting regions at the nanoscale. The results showed a non-uniform Fe distribution of as-received crystals and the formation of new phases in the surface layer of reduced/oxidized samples. The oxidation procedure led to a separation of Ti(Fe) and Sr, while the reduction resulted in the tendency of Fe to agglomerate and migrate away from the surface as seen from the time of flight mass spectroscopy measurements. Moreover, a clear presence of Fe-rich nano-filament in the reduced sample was found.

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