Symmetric “Double Spiro” Wide Energy Gap Hosts for Blue Phosphorescent OLED Devices

AbstractInvestigation of a family of bulk cubic compounds with general formula AgPbmMS2+m (M = Sb, Bi) is reported. These PbS-based cubic structured quaternary systems combine a set of desirable features for efficient ZT thermoelectric materials for solar thermal power generation. AgPbmMS2+m (M = Sb, Bi) possess an average NaCl structure (Fm-3m symmetry), high melting point (991 - 1095 °C for M = Sb; 865 - 1091 °C for M = Bi), relatively wide energy gap (0.7 > Eg (eV) > 0.39 for both Sb and Bi). The systematic variation of lattice parameters, energy gap and melting point is reported. Preliminary charge transport properties are reported along with variable temperature thermal conductivity data of selected members.

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Characterization and Aging Test Methodology for Power Electronic Devices at High Temperature

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.324.411 ◽

2011 ◽

Vol 324 ◽

pp. 411-414 ◽

Cited By ~ 1

Author(s):

Ali Ibrahim ◽

Zoubir Khatir ◽

Laurent Dupont

Keyword(s):

High Temperature ◽

Energy Gap ◽

Switching Frequency ◽

Power Electronic ◽

Active Components ◽

Ambient Temperatures ◽

Test Methodology ◽

Aging Test ◽

Wide Energy ◽

Strategic Issue

Power electronic modules are key elements in the chain of power conversion. The application areas include aerospace, aviation, railway, electrical distribution, automotive, home automation, oil industry ... But the use of power electronics in high temperature environments is a major strategic issue in the coming years especially in transport. However, the active components based on silicon are limited in their applications and not suitable for those require both high voltages and high ambient temperatures. The materials with wide energy gap like SiC, GaN and diamond, have the advantage of being able to exceed these limits [1,2]. These materials seem adequate to extremely harsh temperature environments and allow the reduction of cooling systems, but also the increasing of switching frequency.

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The Structural Stabilities and Electronic Properties of Orthorhombic and Rhombohedral LaCrO3 — A First-Principles Study

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.622-623.734 ◽

2012 ◽

Vol 622-623 ◽

pp. 734-738

Author(s):

Qing Gong Song ◽

Ling Ling Song ◽

Hui Zhao ◽

Tong Wei ◽

Jian Hai Kang

Keyword(s):

Electronic Properties ◽

Density Functional ◽

Energy Gap ◽

Ceramic Materials ◽

Binding Energies ◽

Nano Materials ◽

Functional Theory ◽

Self Consistent Field ◽

Wide Energy ◽

Equilibrium Structures

The equilibrium structures of orthorhombic LaCrO3(O-LaCrO3) and rhombohedral LaCrO3(R-LaCrO3) crystals were investigated by using the plane-wave self consistent field (PWSCF) method based on density functional theory (DFT). The optimized lattice parameters for both phases are in accordance with experimental results reported in literature, confirming the reliability of LSDA+U scheme used in the calculations. We have quantificationally investigated the binding energies and electronic properties of these two types of LaCrO3crystals. The negative total energy and binding energies indicate the ground state property and the good structrual stability of O-LaCrO3crystal, which is important for the preparation of nano materials, the synthesis of ceramic materials made of doped O-LaCrO3crytals, as well as their applications in high technology fields, and predict the metastable property of R-LaCrO3crystal. Furthermore, the band structures show that O-LaCrO3is a direct semiconductor with wide energy gap, while R-LaCrO3is an indirect semiconductor with narrow energy gap. The interaction between Cr and O atoms in O-LaCrO3crystal possesses the character of covalent bonding.

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