scholarly journals Thin Coatings of Cerium Oxide Nanoparticles with Anti-Reflective Properties

2019 ◽  
Vol 9 (18) ◽  
pp. 3886 ◽  
Author(s):  
Laura J. Romasanta ◽  
Lauriane D’Alençon ◽  
Sara Kirchner ◽  
Christophe Pradère ◽  
Jacques Leng

Cerium oxide, in addition to its catalytic properties, is also known for its optical properties such as ultraviolet (UV) radiation filtering and a relatively high refractive index ( n > 2 ), which makes it an excellent candidate for multifunctional coatings. Here, we focus on the optical properties of thin deposits (≲2 μ m) of densely packed C e O 2 nanoparticles, which we assemble using two evaporation-based techniques: convective self-assembly (CSA, a type of very slow blade-coating) to fabricate large-scale coatings of controllable thickness—from tens of nanometres to a few micrometers—and microfluidic pervaporation which permits us to add some micro-structure to the coatings. Spectroscopic ellipsometry yields the refractive index of the resulting nano-porous coatings, which behave as lossy dielectrics in the UV-visible regime and loss-less dielectrics in the visible to infra-red (IR) regime; in this regime, the fairly high refractive index (≈1.8) permits us to evidence thickness-tunable anti-reflection on highly refractive substrates, such as silicon, and concomitant enhanced transmissions which we checked in the mid-IR region.

2019 ◽  
Author(s):  
Mohammad Atif Faiz Afzal ◽  
Mojtaba Haghighatlari ◽  
Sai Prasad Ganesh ◽  
Chong Cheng ◽  
Johannes Hachmann

<div>We present a high-throughput computational study to identify novel polyimides (PIs) with exceptional refractive index (RI) values for use as optic or optoelectronic materials. Our study utilizes an RI prediction protocol based on a combination of first-principles and data modeling developed in previous work, which we employ on a large-scale PI candidate library generated with the ChemLG code. We deploy the virtual screening software ChemHTPS to automate the assessment of this extensive pool of PI structures in order to determine the performance potential of each candidate. This rapid and efficient approach yields a number of highly promising leads compounds. Using the data mining and machine learning program package ChemML, we analyze the top candidates with respect to prevalent structural features and feature combinations that distinguish them from less promising ones. In particular, we explore the utility of various strategies that introduce highly polarizable moieties into the PI backbone to increase its RI yield. The derived insights provide a foundation for rational and targeted design that goes beyond traditional trial-and-error searches.</div>


Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1648
Author(s):  
Muaffaq M. Nofal ◽  
Shujahadeen B. Aziz ◽  
Jihad M. Hadi ◽  
Wrya O. Karim ◽  
Elham M. A. Dannoun ◽  
...  

In this work, a green approach was implemented to prepare polymer composites using polyvinyl alcohol polymer and the extract of black tea leaves (polyphenols) in a complex form with Co2+ ions. A range of techniques was used to characterize the Co2+ complex and polymer composite, such as Ultraviolet–visible (UV-Visible) spectroscopy, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The optical parameters of absorption edge, refractive index (n), dielectric properties including real and imaginary parts (εr, and εi) were also investigated. The FRIR and XRD spectra were used to examine the compatibility between the PVA polymer and Co2+-polyphenol complex. The extent of interaction was evidenced from the shifts and change in the intensity of the peaks. The relatively wide amorphous phase in PVA polymer increased upon insertion of the Co2+-polyphenol complex. The amorphous character of the Co2+ complex was emphasized with the appearance of a hump in the XRD pattern. From UV-Visible spectroscopy, the optical properties, such as absorption edge, refractive index (n), (εr), (εi), and bandgap energy (Eg) of parent PVA and composite films were specified. The Eg of PVA was lowered from 5.8 to 1.82 eV upon addition of 45 mL of Co2+-polyphenol complex. The N/m* was calculated from the optical dielectric function. Ultimately, various types of electronic transitions within the polymer composites were specified using Tauc’s method. The direct bandgap (DBG) treatment of polymer composites with a developed amorphous phase is fundamental for commercialization in optoelectronic devices.


JETP Letters ◽  
2000 ◽  
Vol 72 (9) ◽  
pp. 445-448 ◽  
Author(s):  
A. N. Oraevskii ◽  
I. E. Protsenko

2015 ◽  
Vol 754-755 ◽  
pp. 881-885
Author(s):  
Rafiza Ramli ◽  
Ng Chee Mang ◽  
Zulkifli Ahmad ◽  
Mariatti Jaafar ◽  
Mohd Remy Rozainy Mohd Arif Zainol

A series of high refractive index of α,ω-vinyl silyl terminated polydimethylsiloxane-co-polydiphenylsiloxane was synthesized by the equilibration ring opening – anionic polymerization of cyclic organo-siloxane oligomers in the present of 1,3-divinyltetramethyldisiloxane as terminating agent. Structural modifications were characterized by use of FTIR, H-NMR, and solution viscosity. UV-visible spectroscopy was analyzed which reveal a good transmittance in the region 400 – 750 nm radiation for all polysiloxanes.The presence of diphenylsiloxane unit results in a linear increase of the refractive index of the resin. These features favor good application as encapsulant for high brightness LED (HBLED) packaging.


2017 ◽  
Vol 101 (4) ◽  
pp. 1500-1507 ◽  
Author(s):  
Zhaozhao Mao ◽  
Chaoyue Wang ◽  
Xiaojie Zheng ◽  
Jianding Yu ◽  
Liangming Xiong

2008 ◽  
Vol 3 ◽  
pp. 103-114 ◽  
Author(s):  
Guadalupe Valverde-Aguilar ◽  
Jorge A. García-Macedo ◽  
Víctor Rentería-Tapia

Metallic silver particles in the nanometer size range were obtained in SiO2 matrix by the reduction of AgNO3 with the non-ionic diblock copolymer (Brij 58). Hexagonal mesostructured sol-gel films were synthesized by dip-coating method using the surfactant Brij58 to produce channels into the film, which house the silver nanoparticles. Optical properties of the metallic nanoparticles were studied by UV-Vis spectroscopy, TEM and HRTEM images. The experimental absorption spectrum of the metallic silver nanoparticles exhibits an absorption band located at 438 nm and a shoulder at longer wavelength. The TEM images show randomly distributed silver nanoparticles (Type I) along with some oriented as long line (Type II). Both distributions exhibit a silver oxide shell around of them. The second shell covering the silver core - silver oxide shell system is related to the surfactant. The optical absorption spectrum was modelled using the Gans theory. The fit shows two main contributions related to metallic silver nanoparticles with different axial ratios, and surrounding of a dielectric medium with high refractive index. Presence of the high refractive index silver oxide shell was confirmed by X-ray diffraction technique. The contributions of silver core and silver oxide shell play important roles in the optical properties of the films.


2019 ◽  
Vol 11 (11) ◽  
pp. 1148-1154
Author(s):  
Hamza A. Mezerh ◽  
Kadhim J. Kadhim ◽  
Hamad Rahman Jappor

Density functional theory (DFT) have been used to examine the electronic and optical, properties of two-dimensional (2D) indium selenide (InSe) nanosheet. Our calculations indicate that the energy band gap of InSe is indirect and equal to 1.53 eV. It can be seen that for the pristine case, the majority and minority density of state (DOS) are fully symmetric. The optical properties are considered up to 36 eV. Our results established that the absorption starts in the visible region, while the peaks in the ultraviolet region. The refractive index value is 1.84 at zero photon energy limit and increase to 2.31. The high refractive index allows this nanosheet to be utilized as an internal layer coating between the substrate and the ultraviolet absorbing layer. Additionally, we observed that the gained optical properties of InSe nanosheet are in the ultraviolet range and the results are significant. It is expected that from these calculations to provide useful information for further experimental investigations of InSe nanosheet.


2014 ◽  
Vol 979 ◽  
pp. 135-138 ◽  
Author(s):  
Yotsakit Ruangtaweep ◽  
Jakrapong Kaewkhao

In this work, the physical and optical properties of soda-lime-borate glasses doped with V2O5 concentration of 0.0 to 2.5 in mol% have been investigated. The glass samples were prepared by the normal melt-quench technique. The results show that the density and refractive index decreased with additional 0.5 mol% content of V2O5. Then both results increased with increasing V2O5 content from 1.0-2.5 mol%. The optical absorption spectra of glass samples were measured by UV-visible spectrophotometer in the wavelength range 300-1100 nm and color coordinate in CIEL*a*b* system. The absorption peaks locate around 605 and 960 nm for all V2O5 concentration that are associated to V4+ ions and produce the brown color.


Author(s):  
Chang-Sik Choi ◽  
Ji-Sun Lee ◽  
Mi-Jai Lee ◽  
Young-Jin Lee ◽  
Dae-Woo Jeon ◽  
...  

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Shiyu Yin ◽  
Hao Wang ◽  
Aifeng Li ◽  
Haoyu Huang ◽  
Jing Zhang ◽  
...  

The tellurite 60TeO2-20PbO-(20-x)ZnO-xBaF2 (x = 1, 3, 5, 6, 7, 9, and 11) series glass samples were prepared. The samples’ SEM, XRD, DSC, density, refractive index, and absorption spectra were tested. A self-made optical platform was used to measure and calibrate the refractive index. The relationship between glass composition and crystallinity was discussed. The effects of density, molar refractive index, and metal standard value on the refractive index of glass samples were studied. The results showed that TPZBF glass has a high refractive index, and the refractive index increases with the increase in BaF2 content.


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