Disorder and compositional dependences in Urbach-Martienssen tails in amorphous (GeTe)x(Sb2Te3)1−x alloys

Shportko, K.

doi:10.1038/s41598-019-42634-8

Cited by 26 publications

(14 citation statements)

References 46 publications

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“…In general, the absorption coefficient (α) often displays an exponential tail below the optical bands. These so-called Urbach tails is defined using the following equation 56 , 57 : with the refers to spectral dependence of absorbance coefficient, is the constant, is known as that represents the photonic energy (eV) and is the Urbach energy quantifying the total energetic disorder of the system. Depending on the metals, for metals typically ranges between 1 and 10 eV at room temperature 58 .…”

Section: Methodsmentioning

confidence: 99%

The physical and optical investigations of the tannic acid functionalised Cu-based oxide nanostructures

Lah

Murthy

Zubir

2022

Sci Rep

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The need for a mild, low-cost, green environment that is able to produce exotic properties of output nanostructures is appealing nowadays. Employing these requirements, the copper (Cu)—based oxide nanostructures have been successfully synthesised via one-pot reaction using biocompatible natural polyphenol, tannic acid (TA) as both the reducing agent and stabiliser at 60, 70 and 80 °C. The structural and optical studies disclosed the effect of TA on the surface morphology, phase purity, elemental composition, optical microstrain and optical intrinsic energy of this mixed Cu2O and CuO nanostructures. The optically based method describes the comparative details of the multi-band gap in the presence of more than one element with overlapping spectra from the first-derivative absorbance curve $$\frac{\Delta E}{\Delta A}$$ Δ E Δ A and the exponential absorbance of Urbach tail energy $${E}_{U}$$ E U towards the conventional Tauc bandgap. The $$\frac{\Delta E}{\Delta A}$$ Δ E Δ A demonstrates that the pronounced effect of TA that Cu2O and CuO nanostructures creates much sensitive first-derivative bandgap output compared to the Tauc bandgap. The results also show that the $${E}_{U}$$ E U reduced as the temperature reaches 70 °C and then experienced sudden increase at 80 °C. The change in the pattern is parallel to the trend observed in the Williamson–Hall microstrain and is evident from the variations of the mean crystallite size $${D}_{m}$$ D m which is also a cause response to the change in temperature or pH. Therefore, the current work has elucidated that the structural and optical correlations on the as-synthesised Cu2O and CuO nanostructures in the presence of TA were the combined reaction of pH change and the ligand complexation reactions. The acquired results suggest a more comprehensive range of studies to further understand the extent relationship between the physical and optical properties of TA functionalised Cu-based oxide nanostructures.

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Section: Methodsmentioning

confidence: 99%

The physical and optical investigations of the tannic acid functionalised Cu-based oxide nanostructures

Lah

Murthy

Zubir

2022

Sci Rep

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“…When photon energy hʋ < E g , the absorption of photons is associated to the existence of localized tail states in the forbidden gap that related to the amorphous nature of material. The width of this tail is known as the Urbach tail that indicates the defect levels in the forbidden band gap and calculated using the following formula [74].…”

Section: Amentioning

confidence: 99%

Synthesis, optical and dielectric properties of polyacryloyloxy imino fluorophenyl acetamide and polyacryloyloxy imino fluorophenyl acetamide-co-polystyrene sulfonate

2022

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Our scope is synthesis a new poly fluorobenzamide oxime ester and study its structural, optical, and dielectric properties. Consequently, ((E)-2-((acryloyloxy)imino)-N-(4-fluorophenyl) acetamide) (AIFPA) was as-synthesized via a condensation reaction of (E)-N-(4-fluorophenyl)-2-(hydroxyimino) acetamide with acrylic acid to polymerize it via free radical polymerization (PAIFPA). over and above, the synthesized PAIFPA was inserted in more polymerization action with polystyrene sulfonate through the grafting process (PAIFPA-co-PSS). The chemical structures and morphology of AIFPA, PAIFPA, and PAIFPA-co-PSS were characterized by 1H NMR, FTIR, and XRD. The crystallinity index of PAIFPA, and PAIFPA-co-PSS was studied, affording that PAIFPA-co-PSS has the highest crystallinity. Moreover, The optical bandgap that obtained from absorbance analysis was encountered to be in the range of 2.6 eV to 3.5 eV. Ultimately, the dielectric properties of PAIFPA, and PAIFPA-co-PSS showed that electric conductivity values ranged from 6.12 × 10–8 to 7.11 × 10–7 S.cm−1, and 5.48 × 10–10 to 7.75 × 10–8 S.cm−1, respectively. It has a great deal of interest of PAIFPA-co-PSS which has wide band gap energy as short-wavelength light absorbers to be used in tandem polymer solar cells.

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“…Addition of fillers (NiO NPs) causes defects in polymer blend matrix. These defects increase the density of localized states, Urbach energy is calculated using the following relation 36 :…”

Section: Optical Propertiesmentioning

confidence: 99%

Structural characterization of PVDF/PVA polymer blend film doped with different concentration of NiO NPs for photocatalytic degradation of malachite green dye under visible light

Ismail

Nasr

2021

J of Applied Polymer Sci

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Structural, optical and photodegradation performance of PVDF/PVA polymer blend doped with different concentration of NiO NPs were studied using casting technique method. The effect of adding NiO NPs on PVDF/PVA are investigated using X-ray Diffraction (XRD), High Resolution Transmission Electron Microscope (HRTEM), Fourier Transform Infrared-Attenuated Total Reflection (FTIR-ATR), Ultraviolet-Visible Spectroscopy (UV-Vis), and High Resolution Scanning Electron Microscope (HRSEM). XRD results showed that the addition of NiO NPs increase the crystallinity of PVDF/PVA. The appearance and shifting of bands in FTIR-ATR indicate the structural change in the PVDF/PVA with adding NiO NPs combined with decrease in the band gap of nanocomposite films compared to pure blend in UV-Vis confirmed the incorporation of NiO NPs in PVDF/PVA. HRTEM shows

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Disorder and compositional dependences in Urbach-Martienssen tails in amorphous (GeTe)x(Sb2Te3)1−x alloys

Cited by 26 publications

References 46 publications

The physical and optical investigations of the tannic acid functionalised Cu-based oxide nanostructures

The physical and optical investigations of the tannic acid functionalised Cu-based oxide nanostructures

Synthesis, optical and dielectric properties of polyacryloyloxy imino fluorophenyl acetamide and polyacryloyloxy imino fluorophenyl acetamide-co-polystyrene sulfonate

Structural characterization of PVDF/PVA polymer blend film doped with different concentration of NiO NPs for photocatalytic degradation of malachite green dye under visible light

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