Control of optical properties of silica glass synthesized by VAD method for photonic components

Santos, Juliana S.; Ono, Eduardo Akifumi; Fujiwara, Eric; Manfrim, Tarcio P.; Suzuki, Carlos K.

doi:10.1016/j.optmat.2011.03.007

Cited by 16 publications

(14 citation statements)

References 8 publications

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“…During fused silica glass synthesis, different deposition surface shapes are formed when the inlet gas and burner‐substrate distance are changed, since these process parameters have great influences on the particle distributions (size and number density) and chemical reactions at the surface, and these will finally result in different distributions of SiO 2 deposition rate and deposition surface shapes. For instance, experimental results have shown that the convex deposition surface shapes are formed when the unimodal particle distributions are obtained at the suitable operating conditions and if the particle distribution becomes uniform, the deposit shape becomes flat as well . To investigate the influences of deposit shapes, three kinds of typical deposition surface shapes are modeled in this paper, as shown in Figure .…”

Section: Computational Detailsmentioning

confidence: 99%

“…For instance, experimental results have shown that the convex deposition surface shapes are formed when the unimodal particle distributions are obtained at the suitable operating conditions and HUANG if the particle distribution becomes uniform, the deposit shape becomes flat as well. 6 To investigate the influences of deposit shapes, three kinds of typical deposition surface shapes are modeled in this paper, as shown in Figure 2. Additionally, SiCl 4 injection is crucial for SiO 2 deposition distribution and deposition surface shape formation.…”

Section: Problem Descriptionsmentioning

confidence: 99%

“…In the past, the experimental studies had found that the axial fluctuations of refractive index in silica glass could be greatly reduced by adjusting the substrate location to keep the deposition surface shape unchanged . Similarly, Santos et al reported that the stress birefringence of silica glass is smaller than 2 nm/cm when a suitable deposition surface shape is used. The temperature gradient in synthetic glass during the annealing is crucial to affect the refractive index uniformity of glass.…”

Section: Introductionmentioning

confidence: 99%

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Formation and optimization of deposition surface shape during fused silica glass synthesis by chemical vapor deposition

Huang

2019

Int J of Appl Glass Sci

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This paper investigates the effects of deposition surface shape on temperature distribution of fused silica glass by SiCl4 chemical vapor deposition and performs the optimization of deposition surface shape to obtain the glass with a small temperature gradient. The computational model is first developed to describe the complicated physical and chemical phenomenon in the system. Numerical simulations are then performed to evaluate the effects of SiCl4 injection position on flame characteristics and SiO2 deposition rate. It is found that the SiO2 deposition rates with the unimodal, uniform, and bimodal distributions are obtained when SiCl4 is injected from the central, secondary layer and fourth layer nozzles, respectively. The deposition surface shape is mainly determined by the gas temperature gradient and particle number density near the deposition surface. Thereafter, the temperature distributions in synthetic silica glass are presented for the cases with convex, flat, and concave deposition surface shapes. Large temperature gradients exist at the side of glass if the convex and concave surfaces are formed, although a high temperature uniformity is obtained in the center of glass for the convex deposition surface. The optimal surface shape that has a very small temperature gradient in glass is obtained by the optimization of deposition surface depth.

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Section: Computational Detailsmentioning

confidence: 99%

Section: Problem Descriptionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Formation and optimization of deposition surface shape during fused silica glass synthesis by chemical vapor deposition

Huang

2019

Int J of Appl Glass Sci

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“…Soot particles were synthesized by the Vapor Axial Deposition (VAD) method, which has been widely studied for the production of optical fiber preforms 18 . The silica particles produced by this methodology are completely amorphous and present spherical morphology…”

Section: Nanoparticles Preparationmentioning

confidence: 99%

“…The particles morphologies can be precisely controlled by adjusting the gases flow rates, such as H 2 , O 2 , N 2 , and SiCl 4 flow rates, and by controlling the burner-target distance D, the burnertarget inclination angle θ, and the target vertical translation speed v 18,19 , as shown in Figure 1.…”

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confidence: 99%

Kinetic and Thermodynamic Study in Pozzolanic Chemical Systems as an Alternative for Chapelle Test

et al. 2018

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Important properties in cementitious materials, such as concrete, are related to the presence of additives that influence the rigidity and the physical and chemical resistances. For the evaluation of the additive effectiveness, known as pozzolanic activity, a simple procedure, the Chapelle test, is commonly used, and it essentially consists in a reaction between the additive with calcium oxide in aqueous medium. However, such procedure presents limitations in terms of processing time and lack of information regarding the reactions kinetics. In this sense, a simple method based on the kinetic and thermodynamic principles of chemical reactions is proposed, which can be performed using conventional electronic pH sensors. The study provides an alternative methodology with many advantages over the traditional procedure, such as energy and time-savings, more robustness and more confidence. In this paper, three types of silica nanoparticles that can be used as low-cost additives were characterized in relation to their morphology and crystallinity by XRD and SEM, the particles average diameters were obtained and the particles were used for studying the chemical process that takes place during the Chapelle test. Results and the semi-empirical analysis provided strong evidence that the process is an acid-base 1:1 reaction and it was verified that the mean reaction times varied from 64 to 195 min. It is a remarkable result, since the proposed analysis can be performed with simple, fast and low-cost instrumentation and needs only a worksheet software, whereas the Chapelle test takes 16 hours and provides no dynamic information. Besides the limitation that the methodology is not able to quantify and to elucidate the effects of the specific surface area of the particles, which needs a complete BET study, the research provides a significant contribution for the understanding of the pozzolanic process, of great importance in both concrete and ceramic research.

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Fabrication of fluorescent PMMA-carbon nanodots optical films and their feasibility in improving solar cells efficiency using low-cost sustainable materials

Soares,

Cacioppo,

Amato

et al. 2023

Braz. J. Chem. Eng.

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Nitrogen-doped carbon nanodots synthesized from L-arginine and ethylenediamine (NCNDs); citric acidderived carbon nanodots with carboxylic surface groups (α-CDs); and Silica-Cdots hybrids produced through coupling α-CDs to SiO 2 nanoparticles were used for the fabrication of uorescent PMMA-CDs optical lms. PMMA naturally emits luminescence when irradiated by 300-320 nm and the nanoparticles occlusion allows the conversion of a broader UV bandwidth to the visible: emissions around 450 nm are observed for excitations from 330-360 nm. Since this photoluminescence could increase the e ciency of solar energy concentrators and generators, photovoltaic cells were coated with lms obtained with the blue-emitting NCNDs for a proof-of-concept of increasing the cells' e ciencies with such materials. At our preliminary experiments, even using a setup with low contact of the optical polymer lm on silicon surface, a promising increase from 4.24% to 4.72% cell e ciency was observed, showing the feasibility and potential for application of these environmentally friendly materials.

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Control of optical properties of silica glass synthesized by VAD method for photonic components

Cited by 16 publications

References 8 publications

Formation and optimization of deposition surface shape during fused silica glass synthesis by chemical vapor deposition

Formation and optimization of deposition surface shape during fused silica glass synthesis by chemical vapor deposition

Kinetic and Thermodynamic Study in Pozzolanic Chemical Systems as an Alternative for Chapelle Test

Fabrication of fluorescent PMMA-carbon nanodots optical films and their feasibility in improving solar cells efficiency using low-cost sustainable materials

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