Charge Transfer and Bond Lengths in YBa2Cu3−xMxO6+y

1989 ◽  
Vol 156 ◽  
Author(s):  
P. F. Miceli ◽  
J. M. Tarascon ◽  
L. H. Greene ◽  
P. Barboux ◽  
J. D. Jorgensen ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Neutron Scattering ◽  
Bond Valence ◽  
Bond Lengths ◽  
The Relationship

ABSTRACTWe discuss the effects of doping on the Cu chain sites in YBa2Cu3−xMxO6+y. The relationship between bond lengths obtained from neutron scattering and charge transfer is evaluated in terms of bond valence. In particular, it is concluded that removing an oxygen from the chains transfers one electron to the planes.

High efficient T-shape deep-red thermally activated delayed fluorescence emitter: substitution position effect

2021 ◽  
Author(s):  
Kai Zhang ◽  
Jianzhong Fan ◽  
Chuankui Wang ◽  
Lili Lin
Keyword(s):  
Charge Transfer ◽  
Position Effect ◽  
Luminescent Properties ◽  
Delayed Fluorescence ◽  
Molecular Structures ◽  
Transfer Property ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
High Efficient ◽  
The Relationship

Modulating the relationship between molecular structures and luminescent properties as well as the charge transfer property for deep-red thermally activated delayed fluorescence (TADF) emitters has always been a powerful challenge,...

Compressibility and High-Pressure Electrical Resistivity of One-Dimensional Phthalocyanine Conductors: The Relationship with d-π Charge Transfer

1997 ◽  
Vol 296 (1) ◽  
pp. 255-268 ◽  
Author(s):  
Toshihiro Hiejima ◽  
Kyuya Yakushi ◽  
Takafumi Adachi ◽  
Osamu Shimomura ◽  
Keiki Takeda ◽  
...  
Keyword(s):  
High Pressure ◽  
Electrical Resistivity ◽  
Charge Transfer ◽  
One Dimensional ◽  
The Relationship

New perspective on the laser initiation for metal tetrazine complexes: a theoretical study

2021 ◽  
Author(s):  
Junqing Yang ◽  
Gu-Dan Zhang ◽  
Jianguo Zhang ◽  
Dong Chen ◽  
Qi Zhang
Keyword(s):  
Charge Transfer ◽  
Theoretical Study ◽  
Laser Initiation ◽  
New Perspective ◽  
The Relationship

In order to understand the relationship between the laser initiation and the charge transfer of the metal tetrazine complexes (MTCs), several sets of MTCs with different metals and ligands were...

Fast Reverse Intersystem Crossing Over 107 s-1 in Organic Emitters with Inverted Singlet-Triplet Gap via Intramolecular Through Space Charge Transfer

2021 ◽  
Author(s):  
Yafei Wang ◽  
Xinrui Chen ◽  
Robert Pollice ◽  
Bing Li ◽  
Yuanyuan Zhu ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Space Charge ◽  
Intersystem Crossing ◽  
Acceptor Group ◽  
Fluorescent Materials ◽  
High Emission ◽  
Bond Charge ◽  
The Relationship ◽  
Donor Moiety ◽  
Insight Into

Controlling excited state properties to achieve fast reverse intersystem crossing rates of over 107 s-1 is still challenging for intramolecular through-space charge transfer (TSCT) based delayed fluorescent materials. To gain further insight into the relationship between through-space and through-bond charge transfer (TSCT/TBCT), herein, three compounds DPS-24Ac, DPS-25Ac and DPS-OAc were prepared and characterized via NMR, MS and single crystal, in which the diphenylsulfone (DPS) is used as the acceptor group and acridine (Ac) as the donor moiety. Intense emissions from blue to yellow with high emission efficiency of 70-100% are detected for all emitters. Both computations and experiments suggest that compounds DPS-24Ac and DPS-25Ac have a clear TSCT effect and also an inverted adiabatic singlet-triplet gap which can be explained by the kinetic exchange mechanism. Notably, compound DPS-24Ac achieves the highest reverse intersystem crossing rate constant (krISC) of over 107 s-1 via manipulation of both TSCT and TBCT effects. The solution-processed devices display maximum external quantum efficiencies of 21.73, 12.14 and 4.96% for DPS-24Ac, DPS-25Ac and DPS-OAc, respectively. Overall, this work provides a novel avenue to achieve highly-efficient OLED materials with fast rISC by controlling both TSCT and TBCT effects.

SUBSTITUTION EFFECT IN Pr-DOPED YBCO

2006 ◽  
Vol 20 (20) ◽  
pp. 2899-2907
Author(s):  
L. ZHANG ◽  
M. WANG ◽  
Y. Y. XU
Keyword(s):  
Rietveld Refinement ◽  
Reference System ◽  
Structural Changes ◽  
Substitution Effect ◽  
Bond Valence ◽  
X Ray Diffraction ◽  
Dc Magnetization ◽  
X Ray ◽  
Bond Lengths ◽  
Bond Valence Sum

A series of samples of Y 1-x Pr x Ba 2 Cu 3 O y ( YPrBCO ) with 0.05 ≤ x ≤ 0.6 was synthesized and characterized by DC magnetization, X-ray diffraction (XRD), and Rietveld refinement. It is found that besides Pr substitution for Y , a part of Pr substituted for Ba in YBa 2 Cu 3 O y (YBCO), and the amount of Pr in the Y and Ba positions, respectively, is estimated by the refinement with the help of bond valence sum (BVS) calculation. By comparing the correlation of structural changes such as Ba-O (4) and Cu (1, 2)- O (4) bond lengths and superconductivity between our system with the reference system where Pr just replaces Y , structural evidences are found to explain Pr substitution for Ba suppresses Tc more strongly than that for Y .

Effect of Ligands on the Photoluminescence Performance of Ir(III) Complexes: A Theoretical Exploration

2013 ◽  
Vol 798-799 ◽  
pp. 219-222
Author(s):  
Jian Po Zhang ◽  
Li Jin ◽  
Xing Jin ◽  
Xiu Yun Sun ◽  
Fu Quan Bai
Keyword(s):  
Charge Transfer ◽  
Ground State ◽  
Electronic Structures ◽  
Spectroscopic Properties ◽  
Molecular Orbitals ◽  
Experimental Results ◽  
Frontier Molecular Orbitals ◽  
Bond Lengths ◽  
Td Dft

A series of iridium (III) complexes (C^N)2Ir (Pic) (C^N = Phi (1), Ppi (2), Mpfpi (3), and Cpfpi (4) have been investigated theoretically to explore their electronic structures and spectroscopic properties. The calculate bond lengths of Ir-N and Ir-O in the ground state agree well with the corresponding experimental results. At the TD-DFT and PCM levels, 1-4 give rise to absorptions at 359, 360, 348, and 335 nm and phosphorescent emissions at 454 , 469, 441, and 425 nm, respectively. The transitions of 1-4 are all attributed to {[d (Ir)+π (C^N)][π*(C^N) or π*(Pic)]} charge transfer. It is shown that the emissions are significantly dominated by the metal participating in the frontier molecular orbitals and affected by the C^N ligands.

Effect of bond valence on microwave dielectric properties of (Pb1−xCax)(Mg0.33Ta0.67)O3 ceramics

2001 ◽  
Vol 16 (3) ◽  
pp. 817-821 ◽  
Author(s):  
Heung Soo Park ◽  
Ki Hyun Yoon ◽  
Eung Soo Kim
Keyword(s):  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Bond Valence ◽  
Negative Deviation ◽  
Complex Perovskite ◽  
Microwave Frequencies ◽  
Microwave Dielectric ◽  
Dielectric Polarizability ◽  
A Site ◽  
The Relationship

The relationship between the dielectric properties of the complex perovskite (Pb1−xCax)(Mg0.33Ta0.67)O3 ceramics, where 0.45 ≤ × ≤ 0.60, and the dielectric polarizability, related to bond valences of A-site ions, was investigated at microwave frequencies. As the Ca content (x) increased, the deviation of the observed dielectric polarizabilities, calculated by the Clausius–Mosotti equation from the theoretical values calculated by the additivity rule of dielectric polarizability, decreased from −3% to −0.69%. It was found that this deviation was related to the bond valence of the A-site. Smaller negative deviation corresponded to the cations with lower bond valence, and larger negative deviation corresponded to the cations with higher bond valence. Also, the temperature coefficient of resonant frequency (TCF) was affected by the bond valence of the A-site, and then TCF decreased with decreasing bond valence of the A-site in ABO3 perovskite compounds.

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