Preparation of n-type polyaniline/hexagonal boron nitride composites with a large thermoelectric power factor

2021 ◽  
pp. 096739112110425
Author(s):  
Volkan Ugraskan ◽  
Ebubekir Ceran ◽  
Ozlem Yazici
Keyword(s):  
Boron Nitride ◽  
Power Factor ◽  
Hexagonal Boron Nitride ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
X Ray Diffraction ◽  
Thermoelectric Power Factor ◽  
X Ray ◽  
Seebeck Coefficients ◽  
Vis Spectroscopy

In the present study, it was aimed to investigate the thermoelectric (TE) properties of polyaniline/hexagonal boron nitride (PANI/h-BN) composites. First, h-BN was synthesized from boric acid and urea. Then, PANI-HCl was synthesized by oxidative chemical polymerization. Finally, the composites were prepared using different weight ratios of h-BN. The composites were characterized using attenuated total reflection accessory attached Fourier-transform infrared spectroscopy, UV-vis spectroscopy, X-ray diffraction, and scanning electron microscopy/energy dispersive X-ray analyzer. TE investigation of the composites showed that the addition of h-BN significantly contributes to the TE properties of PANI-HCl. The addition of h-BN increased the power factor of PANI-HCl from 0.07 μWm−1K−2 to 143.05 μWm−1K−2. Furthermore, all the composites showed negative Seebeck coefficients which are the characteristics of n-type semiconductors.

Physicochemical Characteristics of an Ultra-Thin Hydrophobic Trichlorosilanes Using SiO2 as Adhesion

2019 ◽  
Vol 796 ◽  
pp. 80-87
Author(s):  
Akinsanya Damilare Baruwa ◽  
Esther Titilayo Akinlabi ◽  
Oluseyi Philip Oladijo ◽  
Stephen Akinwale Akinlabi ◽  
Jeff Chinn
Keyword(s):  
Room Temperature ◽  
Electrochemical Impedance ◽  
Physicochemical Characteristics ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Natural Seawater ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrophobic Silane ◽  
Better Than

The aim of the research is to subject the three different silanes to chemical and electrochemical investigations in other to determine the most efficient organic compound. Three types of hydrophobic silanes [Tris (Trimethylsiloxy) silyethyl] dimethylchlorosilane (Alkyl); Tridecafloro-1,1,2,2-tetrahydrooctyltrichlorosilane (FOTS) and Henicosyl-1,1,2,2-tetrahydrododecyltricholrosilane (FDDTS) are presented and investigated. The three silanes are of different composition but are deposited at the same parameters and conditions. The chemical investigation was studied through (attenuated total reflection Fourier-transform infrared (ATR-FTIR) and x-ray diffraction (XRD), while the electrochemical study was conducted through EIS using natural seawater electrolyte at room temperature. From the investigation techniques, only electrochemical impedance results show that FDDTS performed better than both Alkyl and FOTS. The chemical analysis showed the presence of hydrophobic silane on all the coated samples, and no distinction can be drawn from associated peaks.

Effects of CaB2O4 Content on the Sintering Behavior of Hexagonal Boron Nitride

2011 ◽  
Vol 675-677 ◽  
pp. 131-134
Author(s):  
Yu Xia Cao ◽  
Ling Zhong Du ◽  
Wei Gang Zhang
Keyword(s):  
Boron Nitride ◽  
Diffraction Analysis ◽  
Apparent Density ◽  
Cross Sections ◽  
Hexagonal Boron Nitride ◽  
Sintering Behavior ◽  
Rockwell Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes

CaB2O4 was added into hexagonal boron nitride (hBN) to improve the sintering behaviors of hBN. CaB2O4 and hBN were mixed and then pressed into plates. The plates were sintered at 2000°C for 5h under a N2 ambience. The phase compositions with different CaB2O4 contents were examined with X-ray diffraction analysis. The fracture cross-sections of the hBN plates were investigated by SEM. The apparent density and Rockwell hardness were also measured. The results show that the hBN particles had a plate-like shape and the grain sizes of hBN increased with increasing CaB2O4 contents. The apparent density and Rockwell hardness decreased with increasing CaB2O4 contents. When the CaB2O4 content was 15(wt) %, the hBN has the average grain sizes of 3μm in diameter and 200nm in thickness, the apparent density of 1.06 g/cm3 and the Rockwell hardness of 3, respectively.

Enhancement of thermoelectric power factor in CrSi2 film via Si:B addition

2015 ◽  
Vol 29 (27) ◽  
pp. 1550189
Author(s):  
Q. R. Hou ◽  
B. F. Gu ◽  
Y. B. Chen
Keyword(s):  
Electrical Resistivity ◽  
Thermoelectric Power ◽  
Raman Spectra ◽  
Power Factor ◽  
Low Temperatures ◽  
X Ray Diffraction ◽  
Thermoelectric Power Factor ◽  
X Ray ◽  
Large Enhancement ◽  
Diffraction Patterns

In this paper, we report a large enhancement in the thermoelectric power factor in CrSi2 film via Si:B (1 at.% B content) addition. The Si:B-enriched CrSi2 films are prepared by co-sputtering CrSi2 and heavily B-doped Si targets. Both X-ray diffraction patterns and Raman spectra confirm the formation of the crystalline phase CrSi2. Raman spectra also indicate the crystallization of the added Si:B. With the addition of Si:B, the electrical resistivity [Formula: see text] decreases especially at low temperatures while the Seebeck coefficient [Formula: see text] increases above 533 K. As a result, the thermoelectric power factor, [Formula: see text], is greatly enhanced and can reach [Formula: see text] at 583 K, which is much larger than that of the pure CrSi2 film.

scholarly journals AB-stacked nanosheet-based hexagonal boron nitride

2021 ◽  
Vol 77 (2) ◽  
Author(s):  
Jae-Kap Lee ◽  
Jin-Gyu Kim ◽  
K. P. S. S. Hembram ◽  
Seunggun Yu ◽  
Sang-Gil Lee
Keyword(s):  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Metastable Phase ◽  
Stacking Sequence ◽  
Lateral Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Pressure High Temperature ◽  
Crystalline Growth

Hexagonal boron nitride (h-BN) has been generally interpreted as having an AA stacking sequence. Evidence is presented in this article indicating that typical commercial h-BN platelets (∼10–500 nm in thickness) exhibit stacks of parallel nanosheets (∼10 nm in thickness) predominantly in the AB sequence. The AB-stacked nanosheet occurs as a metastable phase of h-BN resulting from the preferred texture and lateral growth of armchair (110) planes. It appears as an independent nanosheet or unit for h-BN platelets. The analysis is supported by simulation of thin AB films (2–20 layers), which explains the unique X-ray diffraction pattern of h-BN. With this analysis and the role of pressure in commercial high-pressure high-temperature sintering (driving nucleation and parallelizing the in-plane crystalline growth of the nuclei), a growth mechanism is proposed for 2D h-BN (on a substrate) as `substrate-induced 2D growth', where the substrate plays the role of pressure.

scholarly journals Catalyst-Free Bottom-Up Synthesis of Few-Layer Hexagonal Boron Nitride Nanosheets

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Shena M. Stanley ◽  
Amartya Chakrabarti ◽  
Joshua J. DeMuth ◽  
Vanessa E. Tempel ◽  
Narayan S. Hosmane
Keyword(s):  
Electron Microscopy ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
X Ray Diffraction ◽  
Bottom Up ◽  
X Ray ◽  
Boron Nitride Nanosheets ◽  
Catalyst Free ◽  
Transmission Electron ◽  
Novel Catalyst

A novel catalyst-free methodology has been developed to prepare few-layer hexagonal boron nitride nanosheets using a bottom-up process. Scanning electron microscopy and transmission electron microscopy (both high and low resolution) exhibit evidence of less than ten layers of nanosheets with uniform dimension. X-ray diffraction pattern and other additional characterization techniques prove crystallinity and purity of the product.

scholarly journals Fabrication of PEDOT: PSS-PVP Nanofiber-Embedded Sb2Te3 Thermoelectric Films by Multi-Step Coating and Their Improved Thermoelectric Properties

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2835
Author(s):  
Sang-il Kim ◽  
Kang Yeol Lee ◽  
Jae-Hong Lim
Keyword(s):  
Thermoelectric Properties ◽  
Power Factor ◽  
Photoelectron Spectroscopy ◽  
Hybrid Composites ◽  
Composite Films ◽  
X Ray Diffraction ◽  
Thermoelectric Efficiency ◽  
X Ray ◽  
Seebeck Coefficients ◽  
Electrical Conductivities

Antimony telluride thin films display intrinsic thermoelectric properties at room temperature, although their Seebeck coefficients and electrical conductivities may be unsatisfactory. To address these issues, we designed composite films containing upper and lower Sb2Te3 layers encasing conductive poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS)- polyvinylpyrrolidone(PVP) nanowires. Thermoelectric Sb2Te3/PEDOT:PSS-PVP/Sb2Te3(ED) (STPPST) hybrid composite films were prepared by a multi-step coating process involving sputtering, electrospinning, and electrodeposition stages. The STPPST hybrid composites were characterized by field-emission scanning electron microscopy, X-ray diffraction, ultraviolet photoelectron spectroscopy, and infrared spectroscopy. The thermoelectric performance of the prepared STPPST hybrid composites, evaluated in terms of the power factor, electrical conductivity and Seebeck coefficient, demonstrated enhanced thermoelectric efficiency over a reference Sb2Te3 film. The performance of the composite Sb2Te3/PEDOT:PSS-PVP/Sb2Te3 film was greatly enhanced, with σ = 365 S/cm, S = 124 μV/K, and a power factor 563 μW/mK.

scholarly journals Solar photodegradation of a textile azo dye using synthesized ZnO/Bentonite

2016 ◽  
Vol 75 (5) ◽  
pp. 1211-1220 ◽  
Author(s):  
B. Boutra ◽  
M. Trari
Keyword(s):  
Azo Dye ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Impregnation Method ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order ◽  
Optical Gap ◽  
Optimal Ph

The present work is devoted to the synthesis of a new photocatalyst ZnO (7.5%)/Bentonite prepared by impregnation method and its successful application for the degradation of Solophenyl Red 3BL (SR 3BL) under solar light (∼660 W/m2). The X-ray diffraction (XRD) indicates mixed phases of the nanocomposite catalyst (ZnO/Bentonite), characterized by scanning electron microscopy, X-ray fluorescence and attenuated total reflection. The optical properties confirm the presence of the Wurtzite ZnO phase with an optical gap of 3.27 eV. The catalyst dose (0.25–1 gL−1), pH solution (2.5–11) and initial dye concentration (5–75 mg/L) are optimized. The optimal pH (∼6.7) is close to the natural environment. The photodegradation yield increases with decreasing the SR 3BL concentration. The equilibrium is reached within 160 min and the data are well fitted by the Langmuir-Hinshelwood model; the SR 3BL disappearance obeys to a first-order kinetic with an apparent rate constant of 10−2 mn−1. The best yield of SR 3BL photodegradation (92%) is achieved for a concentration of 5 mg/L and a catalyst dose of 0.75 gL−1 at free pH.

scholarly journals Synthesis and characterization of four new halloysite–TiO2 nanocomposites.

2013 ◽  
Vol 47 (1) ◽  
pp. 407
Author(s):  
D. Papoulis ◽  
S. Komarneni ◽  
D. Toli ◽  
D. Panagiotaras ◽  
S. Bakalis
Keyword(s):  
Sol Gel ◽  
Particle Morphology ◽  
Anatase Tio2 ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Published Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tio2 Particles

The synthesis as well as the characterization of small-sized TiO2 particles supported on Halloysite are presented. Hallloysite from Utah, USA as well as from Limnos, island Greece, were used to synthesize two nanocomposites for each halloysite with TiO2 to halloysite weight ratios of 80: 20 and 60:40 and compare with published data of well formed nanocomposites of intermediate proportion (70-30) that were previously studied. All nanocomposites were prepared by deposition of anatase (TiO2) on the halloysite tubes using a sol–gel method under hydrothermal treatment at 180 °C. Phase composition, particle morphology and physical properties of these samples were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Attenuated Total Reflection using Fourier Transform Infrared spectroscopy (ATR-FTIR) and N2 surface area analysis by BET. Preparation of all halloysite–TiO2 nanocomposites led to the anticipated good dispersion of anatase particles on halloysite surfaces. ATR-FTIR results revealed the formation of hydrogen bonding between anatase and the outer surfaces of halloysite tubes. All halloysite-TiO2 nanocomposites largely showed interparticle mesopores of about 5.7nm and high SSAs.

scholarly journals Pengamatan Surface Plasmon Resonance pada ZnO Nanorods dengan Menggunakan Konfigurasi Prisma/Au/ZnO

2020 ◽  
Vol 23 (1) ◽  
pp. 27
Author(s):  
Rina Dewi Mayasari ◽  
Ajeng Novita Sari ◽  
Aditya Eka Mulyono ◽  
Agus Setyo Budi ◽  
Ratno Nuryadi
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Zno Nanorods ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
X Ray Diffraction ◽  
X Ray ◽  
20 Nm ◽  
Scanning Electron

Pengamatan fenomena surface plasmon resonance (SPR) telah berhasil dilakukan pada ZnO nanorods yang ditumbuhkan di atas lapisan tipis emas. Sistem SPR menggunakan konfigurasi Kretschmann termodifikasi dimana permukaan prisma dideposisi dengan lapisan tipis emas dan ZnO nanorods (prisma/Au/ZnO). Penumbuhan ZnO nanorods menggunakan metode hidrotermal dengan dua tahapan, yaitu pelapisan ZnO seed dan penumbuhan rods. Waktu penumbuhan divariasikan selama 5 menit, 2 jam, dan 4 jam, pada suhu 95 °C yang diikuti dengan annealing pada suhu 500 °C selama 1 jam. Struktur ZnO dikarakterisasi dengan X-ray diffraction (XRD), field emission scanning electron microscope - energy dispersive X-ray spectroscopy (FESEM-EDS), serta diamati fenomena SPR melalui grafik attenuated total reflection (ATR). Hasil karakterisasi menunjukkan bahwa ZnO nanorods (2 jam dan 4 jam) memiliki struktur kristal heksagonal dengan distribusi ukuran diameter pada rentang 20 nm – 60 nm. Fenomena SPR hanya teramati pada nanopartikel ZnO (5 menit) pada sudut SPR (θSPR) 58,2°. Fenomena SPR tidak terlihat pada ZnO nanorods (2 jam dan 4 jam) dikarenakan panjang rods melebihi 100 nm.

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