A novel approach to band gap engineering of Nano-Ca(OH)2: Nanocomposites with Ag2O

Harish,; Kumar, Pushpendra; Kumar, Vipin; Mishra, Rajneesh Kumar; Gwag, Jin Seog; Singh, Manoj K.; Singhal, Rahul; Bhattacharya, Manjima

doi:10.1016/j.ceramint.2022.07.136

Cited by 7 publications

(8 citation statements)

References 75 publications

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“…The relationship between the band gap energy ( E g ) and the crystallite size ( a ) of a nanoparticle is given by equation (6) as [ 32–34 ] :

E_{g} goodbreak= E_{b} goodbreak+ normalΔ E goodbreak= E_{b} goodbreak+ ([], ({}, h^{2} ((), 1 / {m_{normale}}^{*}) goodbreak+ ((), 1 / {m_{normalp}}^{*})) / 8 a^{2})

In equation (6), the quantity E b denotes the energy band gap for the corresponding bulk material, m e * and m p * are the effective masses of an electron and a hole, respectively, h is the Planck's constant, and a is the radius of the nanoparticle. The value of the second term in equation (6) increases as the magnitude of a decreases.…”

Section: Resultsmentioning

confidence: 99%

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Optical band gap enhancements of chemically synthesized α‐Ni(OH)₂ nanoparticles by a novel technique: Precipitator molarity variation

et al. 2022

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Nickel hydroxide nanoparticles (NHNPs) are extremely important semiconducting materials for applications in energy storage and energy harvesting devices. This study uses a novel variation in molarity of the sodium hydroxide (NaOH) precipitator solution to enhance the direct optical band gap in the NHNPs chemically synthesized by using nickel nitrate hexahydrate (Ni(NO 3 ) 2 Á6H 2 O) as the precursor. The simple, energy benign chemical precipitation route involved the usage of 1 M (Ni (NO 3 ) 2 Á6H 2 O) solutions as the precursor and 0.4 M, 0.6 M, and 0.8 M NaOH solutions as the precipitator solutions. The simple variation in precipitator molarity induces an increase in pH from about 6.9 to 7.5 of the reactant solution. As the molarity of the precursor solution does not change, the change in pH of the reactant solution is equivalent to the change in the pH of the precipitator solution. The NHNPs characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), dynamic light scattering (DLS), Fourier-transform infrared (FTIR) and ultraviolet-visible (UV-vis) techniques confirm a reduction of the nanocrystallite size from about 6.8 to 4.5 nm with a concomitant enhancement in the direct optical band gap energy from about 2.64 to 2.74 eV. The possible mechanisms that could be operative behind obtaining microstructurally tuned (MT)-NHNPs and band gap engineering (BGE) of the MT-NHNPs are discussed from both theoretical and physical process perspectives. Further, the implications of these novel results for possible future applications are briefly touched upon. The reported results might be useful to assess the material as an active electrode to improve the performance of batteries.

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“…The relationship between the band gap energy ( E g ) and the crystallite size ( a ) of a nanoparticle is given by equation (6) as [ 32–34 ] :

E_{g} goodbreak= E_{b} goodbreak+ normalΔ E goodbreak= E_{b} goodbreak+ ([], ({}, h^{2} ((), 1 / {m_{normale}}^{*}) goodbreak+ ((), 1 / {m_{normalp}}^{*})) / 8 a^{2})

Section: Resultsmentioning

confidence: 99%

“…The relationship between the band gap energy (E g ) and the crystallite size (a) of a nanoparticle is given by equation ( 6) as [32][33][34] :…”

Section: Mechanisms Of Band Gap Enhancementsmentioning

confidence: 99%

Optical band gap enhancements of chemically synthesized α‐Ni(OH)₂ nanoparticles by a novel technique: Precipitator molarity variation

et al. 2022

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“…[38][39][40] As such, the Ca(OH) 2 nanoparticles are expected to exhibit photo response and hence possible optoelectronic applications. [40]…”

Section: Ftir Analysis and Optical Behaviourmentioning

confidence: 99%

“…[35] From the UV-Vis spectrum (Figure 2c) and Tauc plot (Figure 2d), the optical band gap energy value of the Ca(OH) 2 nanoparticles is calculated to be 4.35 eV, as expected for a wide band gap semiconductor. [38][39][40] As such, the Ca(OH) 2 nanoparticles are expected to exhibit photo response and hence possible optoelectronic applications. [40]…”

Section: Ftir Analysis and Optical Behaviourmentioning

confidence: 99%

Synthesis, Characterization, and Antibacterial Activity of Calcium Hydroxide Nanoparticles Against Gram‐Positive and Gram‐Negative Bacteria

Harish

Kumari²,

Parihar

et al. 2022

ChemistrySelect

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Calcium hydroxide nanoparticles (Ca(OH)2 NPs) are of great interest in the development of new products due to their antibacterial properties. Chemical precipitation process was used for synthesizing Ca(OH)2 NPs. The synthesized Ca(OH)2 NPs were characterized by using X‐ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Fourier Transmission Infrared Spectroscopy (FTIR), UV‐Visible spectroscopy, DLS (Dynamic Light Scattering) techniques. Ca(OH)2 NPs were assessed for antibacterial activity against gram‐positive bacteria (Bacillus subtilis, Staphylococcus aureus) and gram‐negative bacteria (Escherichia coli, Pseudomonas aeruginosa). The results showed reasonable bactericidal activity and flash out that the antibacterial activity of Ca(OH)2 had an important inhibitory activity against B. subtilis and P. aeruginosa which are gram‐positive and gram‐negative bacteria respectively. Reactive oxygen species (ROS) generation of Ca(OH)2 NPs were also studied and shows significant results against both gram negative and gram positive bacteria. From the analysis of the results, it was observed that Ca(OH)2 shows the best antibacterial activity against gram‐positive bacteria B. subtilis. Further, the possible mechanisms of antibacterial behaviour of Ca(OH)2 against each bacteria were suggested. These outcomes indicate that Ca(OH)2 could be utilized as a functional antibacterial material.

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“…The relationship between the band gap energy (E g ) and the crystallite size 'a' of a nanoparticle is given by the following Equation 4 [31,32] :…”

Section: Mechanism Of Band Gap Reductionmentioning

confidence: 99%

Microstructural tuning and band gap engineering of calcium hydroxides: a novel approach by pH variation

et al. 2022

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Here we report a simple, inexpensive, energy benign, yet novel pH‐driven chemical precipitation technique to achieve microstructural and band gap engineering of calcium hydroxide nanoparticles (CHNPs). The chemical precipitation route involved the use of 0.4–1.6 M Ca(NO3)2.4H2O solutions as the precursor and 1 M NaOH solution as the precipitator. The simple variation in precursor molarity induces a pH change from about 12.4 to 11.3 in the reactant solution. The CHNPs characterized by X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and ultraviolet–visible (UV–Vis) spectroscopy techniques confirm a jump of nanocrystallite size from ~50–70 nm with a concomitant reduction of direct optical band gap energy from ~5.38–5.26 eV. The possible mechanisms that could be operative behind obtaining microstructurally tuned (MT)‐CHNPS and band gap engineering (BGE) are discussed from both theoretical and physical process perspectives. Furthermore, the implications of these novel results for possible futuristic applications are briefly hinted upon.

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A novel approach to band gap engineering of Nano-Ca(OH)2: Nanocomposites with Ag2O

Cited by 7 publications

References 75 publications

Optical band gap enhancements of chemically synthesized α‐Ni(OH)₂ nanoparticles by a novel technique: Precipitator molarity variation

Optical band gap enhancements of chemically synthesized α‐Ni(OH)₂ nanoparticles by a novel technique: Precipitator molarity variation

Synthesis, Characterization, and Antibacterial Activity of Calcium Hydroxide Nanoparticles Against Gram‐Positive and Gram‐Negative Bacteria

Microstructural tuning and band gap engineering of calcium hydroxides: a novel approach by pH variation

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A novel approach to band gap engineering of Nano-Ca(OH)2: Nanocomposites with Ag2O

Cited by 7 publications

References 75 publications

Optical band gap enhancements of chemically synthesized α‐Ni(OH)2 nanoparticles by a novel technique: Precipitator molarity variation

Optical band gap enhancements of chemically synthesized α‐Ni(OH)2 nanoparticles by a novel technique: Precipitator molarity variation

Synthesis, Characterization, and Antibacterial Activity of Calcium Hydroxide Nanoparticles Against Gram‐Positive and Gram‐Negative Bacteria

Microstructural tuning and band gap engineering of calcium hydroxides: a novel approach by pH variation

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Optical band gap enhancements of chemically synthesized α‐Ni(OH)₂ nanoparticles by a novel technique: Precipitator molarity variation

Optical band gap enhancements of chemically synthesized α‐Ni(OH)₂ nanoparticles by a novel technique: Precipitator molarity variation