Quasiparticle corrections for energy gaps in semiconductors

2007 ◽  
pp. 161-177 ◽  
Author(s):  
Friedhelm Bechstedt
Keyword(s):  
Energy Gaps

Clustering-Triggered Efficient Room Temperature Phosphorescence from Nonconventional Luminophores

2019 ◽  
Author(s):  
Shuyuan Zheng ◽  
Taiping Hu ◽  
Xin Bin ◽  
Yunzhong Wang ◽  
Yuanping Yi ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Efficiency ◽  
Spin Orbit Coupling ◽  
Design Rationale ◽  
Emission Mechanism ◽  
Room Temperature Phosphorescence ◽  
Electronic Interactions ◽  
Energy Gaps ◽  
Theoretical Results

Pure organic room temperature phosphorescence (RTP) and luminescence from nonconventional luminophores have gained increasing attention. However, it remains challenging to achieve efficient RTP from unorthodox luminophores, on account of the unsophisticated understanding of the emission mechanism. Here we propose a strategy to realize efficient RTP in nonconventional luminophores through incorporation of lone pairs together with clustering and effective electronic interactions. The former promotes spin-orbit coupling and boost the consequent intersystem crossing, whereas the latter narrows energy gaps and stabilizes the triplets, thus synergistically affording remarkable RTP. Experimental and theoretical results of urea and its derivatives verify the design rationale. Remarkably, RTP from thiourea solids with unprecedentedly high efficiency of up to 24.5% is obtained. Further control experiments testify the crucial role of through-space delocalization on the emission. These results would spur the future fabrication of nonconventional phosphors, and moreover should advance understanding of the underlying emission mechanism.<br>

Advantages of naphthalene as building block for organic solid state laser dyes: Smaller energy gaps and enhanced stability

2021 ◽  
Author(s):  
Yuya Oyama ◽  
Masashi Mamada ◽  
Akihiro Kondo ◽  
Chihaya Adachi
Keyword(s):  
Solid State ◽  
Spontaneous Emission ◽  
Building Block ◽  
Solid State Laser ◽  
Laser Dyes ◽  
Energy Gaps ◽  
Organic Solid ◽  
Organic Laser ◽  
Yellow Region ◽  
Enhanced Stability

Organic laser dyes exhibiting very low amplified spontaneous emission (ASE) thresholds in green and yellow region were developed based on a stilbene structure which is often used for the blue...

Physical origin of photonic energy gaps in the propagation of surface plasmons on gratings

1996 ◽  
Vol 54 (9) ◽  
pp. 6227-6244 ◽  
Author(s):  
W. L. Barnes ◽  
T. W. Preist ◽  
S. C. Kitson ◽  
J. R. Sambles
Keyword(s):  
Surface Plasmons ◽  
Physical Origin ◽  
Energy Gaps ◽  
Photonic Energy

Energy gaps in strainedIn1−xGaxAs/In1−yGayAszP1−zquantum wells grown on (001) InP

1995 ◽  
Vol 51 (7) ◽  
pp. 4296-4305 ◽  
Author(s):  
R. Weihofen ◽  
G. Weiser ◽  
Ch. Starck ◽  
R. J. Simes
Keyword(s):  
Energy Gaps

scholarly journals Optical and electronic properties of some semiconductors from energy gaps

2016 ◽  
Vol 53 ◽  
pp. 123-133 ◽  
Author(s):  
Sunil K. Tripathy ◽  
Anup Pattanaik
Keyword(s):  
Electronic Properties ◽  
Energy Gaps ◽  
Optical And Electronic Properties

Effect of indium replacement by gallium on the energy gaps of InAs/GaAs thin‐layer structures

1991 ◽  
Vol 69 (11) ◽  
pp. 7697-7702 ◽  
Author(s):  
Michio Sato ◽  
Yoshiji Horikoshi
Keyword(s):  
Thin Layer ◽  
Energy Gaps ◽  
Layer Structures

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.

Dithienylbenzobis(thiadiazole) based organic semiconductors with low LUMO levels and narrow energy gaps

2010 ◽  
Vol 46 (19) ◽  
pp. 3265 ◽  
Author(s):  
Takahiro Kono ◽  
Daisuke Kumaki ◽  
Jun-ichi Nishida ◽  
Shizuo Tokito ◽  
Yoshiro Yamashita
Keyword(s):  
Organic Semiconductors ◽  
Energy Gaps

scholarly journals Refractive indices of semiconductors from energy gaps

2015 ◽  
Vol 46 ◽  
pp. 240-246 ◽  
Author(s):  
S.K. Tripathy
Keyword(s):  
Refractive Indices ◽  
Energy Gaps
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