Inorganic Acid Doped Polyaniline Based Carbon Monoxide (Co) Sensor

Simple in situ chemical oxidation method was employed to prepare different molar of HCl doped DL−PLA/PANI composites using AnHCl as precursor. Surface morphology, ATR−FTIR, UV–Visible, and band gap were studied. PANI nanowires with different diameter and smooth surface were observed for composites. The lowest direct band gap was found to be 1.68 eV for 2 (M) HCl doped DL−PLA/PANI. DC conductivity at room temperature was measured and followed the ohmic behaviour. The calculated highest DC conductivity at room temperature was found to be 0.1628 × 10−2 (S/cm) for 2 (M) HCl doped DL−PLA/PANI. Temperature variation (70−300 K) DC conductivity without magnetic field of as prepared composites was analysed using linear four probe techniques and showed semiconducting nature. The conductivity in the range of temperature (70−300 K) follows 3D VRH hopping mechanism. In kivelson model, the exponents are increased with increasing dopant concentration and was obeyed the power law. MR of the prepared DL−PLA/PANI composite films is strongly dependent on temperature, magnetic field, and concentration of HCl dopant. Negative MR is discussed in terms of a wave function−shrinkage effect on hopping conduction. In addition, we were discussed the response of carbon monoxide (CO) gas with polyaniline-based sensor materials.

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DL-Polylactide (DL-PLA) Based Polyaniline Composite for Hydrogen Gas Sensors

10.34256/ioriip2125 ◽

2021 ◽

pp. 149-171

Author(s):

Muktikanta Panigrahi ◽

◽

Basudam Adhikari ◽

Keyword(s):

Magnetic Field ◽

Band Gap ◽

Conduction Mechanism ◽

Chemical Oxidation ◽

Hydrogen Gas ◽

Visible Absorption ◽

In Situ Chemical Oxidation ◽

Hydrogen Gas Sensors ◽

Direct Band ◽

Chemical Groups

Different inorganic acids like HCl, HNO3, H2SO4 and H3PO4-doped based DL-PLA/PANI-ES composites were synthesized by in-situ chemical oxidation polymerization technique using liquid aniline as precursors. The doped composite have observed fibril-like morphology with different average sized diameter (178 nm for HCl doped composite, 162 nm (H2SO4 doped composite), 153 nm (H3PO4 doped composite) and 163 nm (HNO3 doped composite), respectively. Analysis of presence of functional groups and other chemical groups of as prepared composites was done by FTIR experiment in ATR mode. The optical (direct) band gap was estimated from UV-Visible absorption spectra. The estimated band gap values are to be 160 eV, 1.37 eV, 1.46 eV, and 1.69 eV for HCl, HNO3, H2SO4 and H3PO4-doped DL-PLA/PANI-ES composite, respectively. The electrical conduction mechanism of HCl-, H2SO4- and H3PO4-doped DL-PLA/PANI-ES composites were taken to study the conduction mechanism in detail in the low temperature regime (77-300 K) with and without applied of the magnetic field. Different models such as variable range hopping (VRH) and Arrhenius model were taken to explain the conduction mechanism of as prepared composites. In the Mott type VRH model, the density of states at the Fermi level, which is constant in the temperature range of 77-300 K were estimated. In the absence of magnetic field, DC conductivity of HCl-, H2SO4- and HNO3-, H3PO4- doped DL-PLA/PANI-ES composite was measured. Also, magnetoresistance (MR) was measured at room temperature for as prepared doped DL-PLA/PANI-ES composites and showed negative MR. In addition, we were discussed the response of hydrogen (H2) gas with polyaniline-based sensor materials.

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OPTICAL ABSORPTION BEHAVIOR OF Co (II) ION DOPED PVA ASSISTED CdSe NANOPARTICLES

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194513010349 ◽

2013 ◽

Vol 22 ◽

pp. 346-350

Author(s):

K. RAVINDRANADH ◽

R. V. S. S. N. RAVIKUMAR ◽

M. C. RAO

Keyword(s):

Band Gap ◽

Room Temperature ◽

Urbach Energy ◽

Wavelength Region ◽

Wide Band ◽

Cdse Nanoparticles ◽

Poly Vinyl Alcohol ◽

Wide Band Gap ◽

Direct Band ◽

Bulk Band

CdSe is an important II-VI, n-type direct band gap semiconductor with wide band gap (bulk band gap of 2.6 eV) and an attractive host for the development of doped nanoparticles. Poly vinyl alcohol (PVA) is used as a capping agent to stabilize the CdSe nanoparticles. The optical properties of Co (II) ion doped PVA capped CdSe nanoparticles grown at room temperature are studied in the wavelength region of 200-1400 nm. The spectrum of Co (II) ion doped PVA capped CdSe nanoparticles exhibit five bands at 1185, 620, 602, 548 and 465 nm (8437, 16125, 16607, 18243 and 21499 cm-1). The bands observed at 1185, 548 and 465 nm are correspond to the three spin allowed transitions 4T1g (F) → 4T2g (F), 4T1g (F) → 4A2g (F) and 4T1g (F) → 4T1g (P) respectively. The other bands observed at 602 nm and 620 nm are assigned to spin forbidden transitions 4T1g (F) → 2T2g (G), 4T1g (F) → 2T1g (G) . The small value of the Urbach energy indicates greater stability of the prepared sample.

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Direct band gap light emission and detection at room temperature in bulk germanium diodes with HfGe/Ge/TiN structure

Thin Solid Films ◽

10.1016/j.tsf.2015.09.074 ◽

2016 ◽

Vol 602 ◽

pp. 43-47 ◽

Cited By ~ 3

Author(s):

Dong Wang ◽

Takayuki Maekura ◽

Keisuke Yamamoto ◽

Hiroshi Nakashima

Keyword(s):

Band Gap ◽

Room Temperature ◽

Light Emission ◽

Direct Band Gap ◽

Direct Band

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Room-temperature direct band-gap electroluminescence from germanium (111)-fin light-emitting diodes

Japanese Journal of Applied Physics ◽

10.7567/jjap.56.032102 ◽

2017 ◽

Vol 56 (3) ◽

pp. 032102 ◽

Cited By ~ 1

Author(s):

Kazuki Tani ◽

Shin-ichi Saito ◽

Katsuya Oda ◽

Makoto Miura ◽

Yuki Wakayama ◽

...

Keyword(s):

Band Gap ◽

Room Temperature ◽

Light Emitting Diodes ◽

Light Emitting ◽

Direct Band Gap ◽

Direct Band

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Indium Sulfide and Ternary In-S-O Nanowires for Optoelectronic Applications

Microscopy and Microanalysis ◽

10.1017/s1431927612013268 ◽

2012 ◽

Vol 18 (S5) ◽

pp. 121-122 ◽

Cited By ~ 1

Author(s):

J. Bartolomé ◽

D. Maestre ◽

A. Cremades ◽

J. Piqueras

Keyword(s):

Solar Cell ◽

Band Gap ◽

Material Properties ◽

Room Temperature ◽

High Efficiency ◽

Processing Parameters ◽

Indium Sulfide ◽

Direct Band Gap ◽

Direct Band ◽

Optoelectronic Applications

Indium sulfide (In2S3) is a promising semiconductor material for window layers in solar cell devices and other optoelectronic applications as it presents a direct band gap around 2.0 eV at room temperature, and large photosensitivity and photoconductivity. The presence of several polymorphic structures depending on the processing parameters is also of interest to tailor the required material properties for different applications. It is currently being investigated for high efficiency solar cell based on CuInS2-In2S3 heterostructures, replacing CdS layers. Few studies have been reported on nanostructured In2S3 grown by several methods.

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Room temperature direct band gap emission characteristics of surfactant mediated grown compressively strained Ge films

Nanotechnology ◽

10.1088/0957-4484/27/43/435204 ◽

2016 ◽

Vol 27 (43) ◽

pp. 435204 ◽

Cited By ~ 3

Author(s):

Ajit K Katiyar ◽

Andreas Grimm ◽

R Bar ◽

Jan Schmidt ◽

Tobias Wietler ◽

...

Keyword(s):

Band Gap ◽

Room Temperature ◽

Emission Characteristics ◽

Direct Band Gap ◽

Direct Band

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Poly Methyl Methacrylate (Pmma) Based Polyaniline Composite for Ammonia (Nh3) Gas Sensors

10.34256/ioriip2126 ◽

2021 ◽

pp. 172-190

Author(s):

Muktikanta Panigrahi ◽

◽

Basudam Adhikari ◽

Keyword(s):

Band Gap ◽

Band Gap Energy ◽

Dc Conductivity ◽

Polymerization Process ◽

Visible Absorption ◽

Inorganic Acids ◽

Pani Composite ◽

Direct Band ◽

Uv Visible

Inorganic acids (HCl, H2SO4, and H3PO4) doped-PMMA/PANI composites are prepared by in-situ technique via oxidation-polymerization process. Different techniques such as XRD, FTIR, UV-Visible, four-probe method are used to characterize the composite. Presence of different chemical group of the doped composites is analysed by ATR-FTIR spectroscopic analysis. Charge carrier behaviour of the doped composite is analyzed by UV-Visible spectroscopy. Band gap (Eg) of the doped composites is determined from UV-Visible absorption analysis using Tauc expression. The estimated direct band gap energy (Eg) is found to be 1.93 eV (for HCl doped PMMA/PANI composite), 1.19 eV (for H2SO4 doped PMMA/PANI composite), and 1.71 eV (for H3PO4 doped PMMA/PANI composite), respectively. DC-conductivity is measured with and without magnetic field. Temperature dependent DC conductivity is also measured. In addition, we were discussed the response of ammonia (NH3) gas with polyaniline-based sensor materials.

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Direct band gap electroluminescence from bulk germanium at room temperature using an asymmetric fin type metal/germanium/metal structure

Applied Physics Letters ◽

10.1063/1.4913261 ◽

2015 ◽

Vol 106 (7) ◽

pp. 071102 ◽

Cited By ~ 11

Author(s):

Dong Wang ◽

Takayuki Maekura ◽

Sho Kamezawa ◽

Keisuke Yamamoto ◽

Hiroshi Nakashima

Keyword(s):

Band Gap ◽

Room Temperature ◽

Metal Structure ◽

Direct Band Gap ◽

Direct Band

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Synergistic effect by Na doping and S substitution for high thermoelectric performance of p-type MnTe

Journal of Materials Chemistry C ◽

10.1039/c7tc01480e ◽

2017 ◽

Vol 5 (21) ◽

pp. 5076-5082 ◽

Cited By ~ 21

Author(s):

Yangyang Ren ◽

Junyou Yang ◽

Qinghui Jiang ◽

Dan Zhang ◽

Zhiwei Zhou ◽

...

Keyword(s):

Electrical Conductivity ◽

Synergistic Effect ◽

Band Gap ◽

Room Temperature ◽

Hole Concentration ◽

Direct Band Gap ◽

Na Doping ◽

Type Semiconductor ◽

Direct Band ◽

P Type

Pristine MnTe is a p-type semiconductor with a relatively low hole concentration of 1018 cm−3, low electrical conductivity, and thus poor TE performance at room temperature owing to the broad direct band gap of 1.27 eV.

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