scholarly journals Impact of Dopants on the Electrical and Optical Properties of Hydroxyapatite

Biomaterials ◽  
2020 ◽  
Author(s):  
Kumaravelu Thanigai Arul ◽  
Jayapalan Ramana Ramya ◽  
Subbaraya Narayana Kalkura
Keyword(s):  
Dielectric Constant ◽  
Optical Properties ◽  
Energy Levels ◽  
Transmission Band ◽  
Electrical Current ◽  
Band Gaps ◽  
Polarization Phenomenon ◽  
Surface Charges ◽  
Future Outlook ◽  
Insight Into

This chapter deals with the effect of alternating electrical current on hydroxyapatite [HAp, Ca10(PO4)6(OH)2] and doped HAp along with their optical response and the processes involved. The dielectric constant, permittivity and ac conductivity were analyzed to have an insight into the surface charge polarization phenomenon. Further, the magnitude and the polarity of the surface charges, microstructure, and phases also play significant role in the cell proliferation and growth on the implants. Besides, the mechanism behind the electrical properties and the healing of bone fracture are discussed. The influence of various dopants on the optical properties of HAp viz., absorbance, transmission, band gaps and defects energy levels are analyzed along with the photoluminescence and excitation independent emission. In the future outlook, the analysis of effect of doping is summarized and its impact on the next generation biomaterials are elucidated.

scholarly journals Effect of High Density Polyethylene (HDPE) on Structural and Optical Properties of (PP/PMMA) Blends

2015 ◽  
Vol 60 ◽  
pp. 94-106
Author(s):  
Majeed Ali Habeeb ◽  
Ahmed Hamza Abbas
Keyword(s):  
Dielectric Constant ◽  
Optical Properties ◽  
High Density Polyethylene ◽  
Refraction Index ◽  
High Density ◽  
Band Gaps ◽  
Ir Spectrometry ◽  
Ft Ir ◽  
Pmma Blends ◽  
Dielectric Constant Increase

In the present work, Polypropylene (PP) was blended with poly methyl methacrylate (PMMA) to form (PP/PMMA) polymer blends. High Density Polyethylene (HDPE) was mixed into these blends at different weight fractions (2,4,6,8) % wt to form (PP/PMMA/HDPE) blends were prepared using an one screw extruder. results obtained from Scanning Electron Microscopy (SEM) revealed that there was a reduction in surface roughness any decrease in clusters, drilling and bends, as for Fourier Transform Infrared (FT-IR) spectrometry showed no change in the wave numbers of the functional groups. The optical properties of samples are investigated by measuring optical absorption spectra in the wavelength range from 260 to 1100 nm. this results show that Eg of the blends increases with increasing high density polyethylene contents, the indirect optical band gaps for (PP/PMMA) and (PP/PMMA/HDPE) blends were estimated to be about 2.83,2.9,2.95,3and 3.1 eV for indirect allowed transitions, whereas the indirect forbidden band gaps were determined as 2,2.1,2.15,2.2 and 2.3 eV with increase high density Polyethylene contents, respectively. The absorbance, absorption coefficient, extinction coefficient and the imaginary dielectric constant of (PP/PMMA/HDPE) decreases with increasing of HDPE percentages except the transmittance, refraction index and real part of the dielectric constant increase with increasing of high density polyethylene.

Optical properties of HgS and HgS : Co2+ crystals

1991 ◽  
Vol 6 (12) ◽  
pp. 2677-2679 ◽  
Author(s):  
Sung-Hyu Choe ◽  
Ki-Su Yu ◽  
Jae-Eun Kim ◽  
Hae Yong Park ◽  
Wha-Tek Kim
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Room Temperature ◽  
Energy Levels ◽  
Band Gaps ◽  
Electronic Transitions ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Optical Absorption Spectra ◽  
Coupling Parameters

Melt-grown crystals of HgS and HgS : Co2+ were used to measure their optical absorption spectra. The optical energy band gaps of these crystals were 2.030 eV and 1.870 eV at room temperature, respectively. The impurity optical absorption peaks of Co2+ were observed at 4030, 5988, 12285, 12672, and 12905 cm−1. These peaks can be attributed to the electronic transitions between the split energy levels of Co2+ ion located at the Td symmetry site, where the crystal field, Racah, and spin-orbit coupling parameters were given by Dq = 403, B = 427, and Λ = −155 cm−1, respectively.

scholarly journals Chemical Vapor Deposition Synthesis and Optical Properties of Nb2O5 Thin Films with Hybrid Functional Theoretical Insight into the Band Structure and Band Gaps

2017 ◽  
Vol 9 (21) ◽  
pp. 18031-18038 ◽  
Author(s):  
Sanjayan Sathasivam ◽  
Benjamin A. D. Williamson ◽  
Shaeel A. Althabaiti ◽  
Abdullah Y. Obaid ◽  
Sulaiman N. Basahel ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Chemical Vapor Deposition ◽  
Band Structure ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Band Gaps ◽  
Hybrid Functional ◽  
Theoretical Insight ◽  
Insight Into

Electronic and optical properties of mixed Sn–Pb organohalide perovskites: a first principles investigation

2015 ◽  
Vol 3 (17) ◽  
pp. 9208-9215 ◽  
Author(s):  
Edoardo Mosconi ◽  
Paolo Umari ◽  
Filippo De Angelis
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Energy Levels ◽  
Hole Transport ◽  
Band Gaps ◽  
Electron Hole ◽  
Electronic And Optical Properties

We investigate MASnxPb(1−x)I3 perovskites by first-principles simulations, finding monotonic variation of energy levels and band-gaps, and demonstrating balanced electron/hole transport.

ELECTRONIC AND OPTICAL PROPERTIES OF PERFECT MgO AND MgO WITH F CENTER UNDER HIGH PRESSURE

2013 ◽  
Vol 24 (08) ◽  
pp. 1350052 ◽  
Author(s):  
J. ZHANG ◽  
Z. ZENG
Keyword(s):  
High Pressure ◽  
Optical Properties ◽  
Electronic Structure ◽  
Oxygen Vacancy ◽  
Applied Pressure ◽  
Band Gaps ◽  
First Principle ◽  
Practical Applications ◽  
F Center ◽  
Insight Into

A first-principle method is used to investigate the electronic structure and optical properties of MgO and MgO containing an oxygen vacancy. In the presence of the oxygen vacancy, a new electronic state appears in the band gap, which leads to additional peaks in the optical spectra. Furthermore, under applied pressure, the band gaps become larger, and the curves of optical properties including the dielectric function ε(ω) and absorption coefficient α(ω) shift towards higher energy. The knowledge of MgO and MgO with F center under high pressure may provide insight into their practical applications.

Dynamics of Ion Locking in Doubly Polymerized Ionic Liquids

2020 ◽  
Author(s):  
Swati Arora ◽  
Julisa Rozon ◽  
Jennifer Laaser
Keyword(s):  
Dielectric Constant ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Ion Pairs ◽  
Polymer Chains ◽  
Ion Motion ◽  
Charged Species ◽  
Broadband Dielectric Spectroscopy ◽  
Covalently Linked ◽  
Insight Into

<div>In this work, we investigate the dynamics of ion motion in “doubly-polymerized” ionic liquids (DPILs) in which both charged species of an ionic liquid are covalently linked to the same polymer chains. Broadband dielectric spectroscopy is used to characterize these materials over a broad frequency and temperature range, and their behavior is compared to that of conventional “singly-polymerized” ionic liquids (SPILs) in which only one of the charged species is attached to the polymer chains. Polymerization of the DPIL decreases the bulk ionic conductivity by four orders of magnitude relative to both SPILs. The timescales for local ionic rearrangement are similarly found to be approximately four orders of magnitude slower in the DPILs than in the SPILs, and the DPILs also have a lower static dielectric constant. These results suggest that copolymerization of the ionic monomers affects ion motion on both the bulk and the local scales, with ion pairs serving to form strong physical crosslinks between the polymer chains. This study provides quantitative insight into the energetics and timescales of ion motion that drive the phenomenon of “ion locking” currently under investigation for new classes of organic electronics.</div>

Molecular Design and Application of a Photovoltaic Polymer with Improved Optical Properties and Molecular Energy Levels

2015 ◽  
Vol 48 (11) ◽  
pp. 3493-3499 ◽  
Author(s):  
Huifeng Yao ◽  
Hao Zhang ◽  
Long Ye ◽  
Wenchao Zhao ◽  
Shaoqing Zhang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Molecular Design ◽  
Energy Levels ◽  
Design And Application
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