Room-Temperature Coherent Optical Phonon in 2D Electronic Spectra of CH3NH3PbI3 Perovskite as a Possible Cooling Bottleneck

2017 ◽  
Vol 8 (14) ◽  
pp. 3211-3215 ◽  
Author(s):  
Daniele M. Monahan ◽  
Liang Guo ◽  
Jia Lin ◽  
Letian Dou ◽  
Peidong Yang ◽  
...  
Keyword(s):  
Optical Phonon ◽  
Electronic Spectra ◽  
Room Temperature

Polar Optical Phonon Instability and Intervalley Transfer in Gallium Nitride

1998 ◽  
Vol 512 ◽  
Author(s):  
B. E. Foutz ◽  
S. K. O'leary ◽  
M. S. Shur ◽  
L. F. Eastman ◽  
B. L. Gelmont ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
Analytical Model ◽  
Optical Phonon ◽  
Room Temperature ◽  
Phonon Scattering ◽  
Polar Optical Phonon ◽  
Scattering Mechanism ◽  
Loss Mechanism ◽  
One Dimensional ◽  
Optical Phonon Scattering

ABSTRACTWe develop a simple, one-dimensional, analytical model, which describes electron transport in gallium nitride. We focus on the polar optical phonon scattering mechanism, as this is the dominant energy loss mechanism at room temperature. Equating the power gained from the field with that lost through scattering, we demonstrate that beyond a critical electric field, 114 kV/cm at T = 300 K, the power gained from the field exceeds that lost due to polar optical phonon scattering. This polar optical phonon instability leads to a dramatic increase in the electron energy, this being responsible for the onset of intervalley transitions. The predictions of our analytical model are compared with those of Monte Carlo simulations, and are found to be in satisfactory agreement.

Copper(II) Dihydroxybenzoates; Synthesis and Properties

1993 ◽  
Vol 58 (6) ◽  
pp. 1363-1370 ◽  
Author(s):  
Jozef Sokolík ◽  
Brigita Lučanská ◽  
Gustáv Plesch ◽  
Ingrid Tumová ◽  
Aladár Valent ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Electronic Spectra ◽  
Room Temperature ◽  
Magnetic Moments ◽  
Tetragonal Distortion ◽  
High Toxicity ◽  
Antipyretic Activity ◽  
Pharmacological Screening ◽  
Cooperative Ordering

Compounds of composition Cu(2,5-DHB)2 . 4 H2O (DHB, dihydroxybenoate anion) and Cu(2,Y-DHB)2 . 8 H2O (Y = 4 or 6) were prepared as potential antiinflamatory gents with a view of pharmacological screening. The room-temperature magnetic moments allow to classify all compounds into the group of magnetically diluted copper(II) complexes. According the EPR and electronic spectra, the degree of tetragonal distortion increases passing from Cu(2,6-DHB)2 . 8 H2O (III) through Cu(2,4-DHB)2 . 8 H2O (I) to Cu(2,5-DHB)2 . 4 H2O (II. The complexes differ also in the cooperative ordering in their structures. All tested compounds exhibit higher antiinflamatory activities (on dextran edema) than free carboxylic acids. However, their effects were accompanied with relatively high toxicity. Remarkable results were also achieved on evaluating the antipyretic activity.

Plasmon induced enhancement of surface optical phonon modes and magnon properties of NiO nanoparticles: Raman spectral probe

2020 ◽  
Vol 22 (39) ◽  
pp. 22815-22822 ◽  
Author(s):  
Anoop Sunny ◽  
Karthikeyan Balasubramanian
Keyword(s):  
Raman Spectroscopy ◽  
Optical Phonon ◽  
Room Temperature ◽  
Nio Nanoparticles ◽  
Phonon Modes ◽  
Surface Optical ◽  
Raman Spectral

In the present work, the influence of Ag-induced plasmons on the surface optical (SO) phonon modes of NiO nanoparticles was extensively studied using room temperature Raman spectroscopy.

Electronic spectra of dibenzo[a,d]cycloheptatrienylidene at 77°K and room temperature

Tetrahedron ◽  
1970 ◽  
Vol 26 (1) ◽  
pp. 251-254 ◽  
Author(s):  
Y. Yamamoto ◽  
I. Moritani ◽  
Y. Maeda ◽  
S. Murahashi
Keyword(s):  
Electronic Spectra ◽  
Room Temperature

Carrier Doping of Silicon Nanowires Synthesized by Laser Ablation

2006 ◽  
Vol 963 ◽  
Author(s):  
Naoki Fukata ◽  
Naoya Okada ◽  
Satoshi Matsushita ◽  
Takao Tsurui ◽  
Shun Ito ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Silicon Nanowires ◽  
Optical Phonon ◽  
Room Temperature ◽  
Vibrational Modes ◽  
Scattering Measurements ◽  
Doped Silicon ◽  
Phonon Peak ◽  
Local Vibrational Modes ◽  
Carrier Doping

ABSTRACTBoron (B) doped silicon nanowires (SiNWs) were synthesized by laser ablation. Local vibrational modes of B in SiNWs were observed by micro-Raman scattering measurements at room temperature. Broadening due to a coupling between the discrete optical phonon and a continuum of interband hole excitations was also observed in the Si optical phonon peak. This is called Fano broadening. These results prove that B atoms were doped in substitutional sites of crystalline Si core of SiNWs during laser ablation.

Dielectric and optical phonon anomalies near antiferromagnetic ordering in LaCrO3: A possible near room temperature magnetodielectric system

2013 ◽  
Vol 103 (15) ◽  
pp. 152906 ◽  
Author(s):  
Brajesh Tiwari ◽  
A. Dixit ◽  
R. Naik ◽  
G. Lawes ◽  
M. S. Ramachandra Rao
Keyword(s):  
Optical Phonon ◽  
Room Temperature ◽  
Antiferromagnetic Ordering

Cooperative Spin Transitions in Iron(II) Derivatives of 1,2,4-Triazole

1994 ◽  
Vol 47 (2) ◽  
pp. 263 ◽  
Author(s):  
KH Sugiyarto ◽  
HA Goodwin
Keyword(s):  
Hysteresis Loop ◽  
Temperature Dependence ◽  
Transition Region ◽  
Electronic Spectra ◽  
Room Temperature ◽  
Coordination Core ◽  
Continuous Transition ◽  
Quintet State ◽  
Derivatives Of ◽  
Perchlorate Salt

Complexes of stoichiometry Fe( trzH )2( trz )X, where trzH is 1,2,4-triazole and X = BF4, ClO4, PF6, have been prepared. All three salts display temperature-induced singlet (1A1) ↔ quintet (5T2) transitions which are generally discontinuous and associated with a broad hysteresis loop. The salts are strongly thermochromic, being white above and pink-lilac below the transition region. Several samples of each salt were obtained and the detailed behaviour varied somewhat from one sample to another. For the fluoroborate and perchlorate salts the transition is centred above room temperature while for the hexafluorophosphate salt it occurs below room temperature. The perchlorate salt was also isolated in a form which showed a continuous transition but the nature of its electronic properties changed as the sample aged. In one form of the hexafluorophosphate salt the hysteresis loop spans room temperature and it has been possible to characterize both the singlet and the quintet state species at that temperature. For all three salts the transition has been characterized by measurement of the temperature dependence of the magnetism and Mossbauer and electronic spectra. These measurements establish that the complexes all contain an FeN6 coordination core and this must be achieved through bridging of the triazole units.

DIFFUSENESS IN ELECTRONIC SPECTRA THE VAPOR SPECTRUM OF ANTHRACENE

1965 ◽  
Vol 43 (12) ◽  
pp. 3253-3257 ◽  
Author(s):  
J. P. Byrne ◽  
I. G. Ross
Keyword(s):  
Electronic Spectra ◽  
Room Temperature ◽  
Sequence Structure ◽  
Short Region ◽  
Sharp Structure ◽  
Singlet Transition

Approximate calculations of the number of rovibronic transitions per unit wavenumber are given for benzene, naphthalene, anthracene, and tetracene. Primarily because of the density of sequence structure all transitions in tetracene vapor should be irresolvably crowded, and hence apparently diffuse, at practical temperatures. Anthracene, whose spectrum has hitherto been described as wholly diffuse, is predicted to be capable of showing resolvable structure at room temperature. At 60 °C and 40 m path a short region of fine sharp structure has been observed. The origin of the first singlet transition is located at 27 688.3 cm−1 (27 757.6 cm−1 in anthracene-d10).

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

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