Increase In Band Gap Energy Research Articles

Pressure-induced band-gap energy increase in a metal iodate

A wide band gap is one of the essential requirements for metal iodates to be used as nonlinear optical materials. Usually, the band gap of these materials decreases under the application of pressure. Herein, we introduce a case in which the band-gap energy of a hydrated metal iodate, namely $\mathrm{Ca}{({\mathrm{IO}}_{3})}_{2}\ifmmode\cdot\else\textperiodcentered\fi{}{\mathrm{H}}_{2}\mathrm{O}$, has been successfully increased, from 4.52 to 4.92 eV, by applying external pressure without showing signs of saturation upon increasing pressure. The pressure-induced nonlinear band-gap opening correlates with the pressure-induced shortening of the I-O bond distances, as obtained from x-ray diffraction measurements. In addition, two pressure-induced isostructural phase transitions are observed in the pressure regions of 6.6--8.0 and 13.0--15.5 GPa. These two isostructural phase transitions cause a nonlinear pressure-induced evolution of the band-gap energy and crystal lattice parameters, as well as the occurrence of several extra peaks and peak splitting in Raman spectra.

Fabrication and infusion of potent silver doped nano ZnO aimed to advance germicidal efficacy of health and hygiene products

This article explores a strategic approach to fabricate nano scale silver (100-2000 ppm) doped zinc oxide (ZnOS) in a unique Surfactant-Polyol-Assembly (SPA) that acts as a caging agent, restricting the growth of particles. This highly suitable approach for health and hygiene products is among the few works of literature exploring the fabrication and infusion of nano ZnOS to elevate the germicidal efficacy of liquid cleansing products significantly. XRD reveals a hexagonal wurtzite structure having an average crystallite size of 15.14 nm, total crystallinity of 97.62% and a high specific surface area of 70.68 m 2 /g. Surface morphological analysis using SEM exhibits monodisperse spherical particles. UV-Vis spectra indicate Burstein-Moss-effect with blue-shift of UV absorbance edge, increase in bandgap energy from 3.55 to 3.64 eV with higher doping. Significant germicidal efficacy of nano ZnOS and infused products having p values < 0.05 compared to AR grade ZnO are established against Gram-positive and Gram-negative pathogens using zone-of-inhibition (ZOI) and European standard EN 1276. Infused products with 0.2% of ZnOS exhibit ZOI up to 13.25 mm with a log reduction of 2.13 while nano ZnOS 2000 ppm shows ZOI up to 11.75 mm with a log reduction of 5.41 which corresponds to >99.999% germ kill. • This study aimed at the fabrication of potent nano scale silver doped zinc oxide (ZnOS) in Surfactant-Polyol-Assembly (SPA) restricting the growth of particles size. • The present study established the advanced germicidal efficacy of fabricated nano ZnOS having >99.999% germ kill. • Fabricated nano ZnOS is infused into liquid cleansing products and established its significant germicidal efficacy for health and hygiene applications.

Towards effective dye degradation and antimicrobial behavior of chitosan and C3N4-doped CdS nanoparticles

In this study, co-precipitation has been employed to develop carbon nitride (C 3 N 4 ) and chitosan (CS)-doped CdS nanoparticles (NPs) to investigate the doping effect of CS and C 3 N 4 on CdS to degrade MB dye and assess their antibacterial activity. Comparatively, the maximum dye degradation achieved by the previously reported binary blend of CdS-C 3 N 4 was 85%, whereas the maximum degradation achieved by the currently prepared ternary nano-catalyst was 99.75%. Furthermore, CdS NPs were doped with a fixed amount of CS at various concentrations (2 and 4 wt. %) of C 3 N 4 . Numerous techniques have been utilized to characterize doped NPs. The hexagonal phase of CdS was confirmed by XRD results, and doping caused a decrease in crystallite size, as calculated by the Debye Scherrer formula. Functional group existence was determined by FTIR; CdS was confirmed at 662 and 758 cm −1 , and doped CdS exhibited bond stretching and absorption at 1061, 1388, 1627, and 3434 cm -1 . The UV-Vis absorption spectra with blueshift after doping resulted in increased bandgap energy, which could be attributed to a reduction in crystallite size. PL spectra were utilized to observe the charge carrier transfer and trap sites of doped NPs. The presence of CdS formation and doping was observed using EDS. The morphology of the product was examined using HRTEM, which revealed spherical NPs agglomeration. C 3 N 4 -doped NPs demonstrated significant methylene blue (MB) dye degradation, while doped CdS samples exhibited considerable antimicrobial activity against Staphylococcus aureus and Escherichia coli bacteria.

Theoretical Studies of the Optical Properties of ZnS , ZnO and CdS Nanopartical Using the Brus Equation

In the present work, Brus equation has been used to study the size effect of the quantum dot on the optical properties of some semiconductor compounds ( CdS, ZnS and ZnO). It is found that the absorption wavelength and bandgap energy are dependent on the size of the QD. As the size of the QD decreases, the bandgap energy increases and the absorption wavelength decreases. There is good agreement of the theoretical results of the bandgap energy and absorption wavelength obtained in this study using Brus equation with the published experimental results for the semiconductor compounds mentioned above.

Studies on photocatalytic performance and supercapacitor applications of undoped and Cu-doped ZnO nanoparticles

The structural, morphology and optical properties were characterised using XRD, FTIR, SEM, TEM, and UV-DRS for the undoped and Cu-doped ZnO NPs with varying Cu doping molar concentrations from 0 wt% to 6 wt% through the co-precipitation method. The presence of a ZnO hexagonal wurtzite structure for all samples was confirmed by the structural study of the Cu-doped ZnO NPs, indicating the incorporation of Cu2+ ions into the ZnO lattice by substitution and average crystallite sizes of 25–22 nm. The surface morphology analysis of undoped and Cu-doped ZnO NPs indicated the growth of spherical nanocrystallites with fine particles. Optical studies of Cu-doped ZnO nanostructured particles revealed that increasing the Cu doping agent from 0 wt% to 6 wt% resulted in a blue shift of the absorption band with increasing band gap energy from 3.27 eV to 3.44 eV. The degradation efficiency of MB is 89.2% for Cu-doped ZnO photocatalyst, which performs much better than undoped ZnO under natural sunlight irradiation. The electrochemical analysis determined the specific capacitance of 10 to 100 mV/s scan rate for all the samples. Amongst the various concentrations, 6 wt% Cu-doped ZnO had the most excellent specific capacitance of 539.87 F/g at 10 mV/s. Compared with undoped ZnO NPs, Cu-doped into the ZnO matrix enhanced photocatalytic activities and electrochemical performance for wastewater treatment and supercapacitor applications.

Synthesis of Al and In dual-doped CuO nanostructures via SILAR method: Structural, optical and electrical properties

In this article, we investigated the doping characteristics of Al-doped CuO (ACO), and Al/In co-doped CuO (AICO) thin films, which were synthesized on glass substrates, via the solution-based successive ionic layer adsorption and reaction (SILAR) technique. The surface morphological, chemical composition, structural, optical, and electrical properties of the nanocrystalline films were characterized by Field Emission Scanning Electron Microscopy (FE-SEM), Energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier-transform Infrared Spectroscopy (FTIR), Ultraviolet–visible (UV–vis.) spectrophotometry, and Transmission Line Method (TLM), respectively. Surface morphology studies exhibited that a decrease in the films' thickness caused an increment in the optical transmittance. XRD patterns displayed that the obtained samples were polycrystalline and crystallized in a bare CuO monoclinic structure. FTIR studies of the CuO samples displayed that Al and In co-doping influenced the forms and the violence of the absorption bands. The optical bandgap energy of bare CuO was determined to increase from 1.45 to 1.78 eV as a result of the co-doping. The substitution of In displayed in the irregularity of the morphology, owing to its wide ionic radius, which caused an increase in band gap energy and a decrease in resistance. The co-doping of Al and In is hence anticipated to ensure an extensive range of physical and optical properties of nanostructured metal oxide samples for a variety of technological applications.

Magnetic Domain Characterization and Physical Properties of Gd-Doped and (Gd, Al) Co-Doped ZnO Thin Films.

Undoped ZnO, Gd-doped ZnO with various doping concentration (1, 3, 5, and 7 at%), and 3 at% (Gd, Al) co-doped ZnO films were prepared on a glass substrate using the co-reactive sputtering method. The influence of the doping and co-doping process on the films was characterized using X-ray diffraction, FESEM, EDX, MFM, VSM, UV-VIS spectroscopy, and the Hall Effect measurement at room temperature. XRD study confirmed that the Gd and Al ions are incorporated into a ZnO lattice. EDX analysis confirmed the existence of Zn, O, Al, and Gd elements in the prepared Gd-doped ZnO and (Gd, Al) co-doped ZnO films, which suggests the successful doping procedure. All the deposited films obtained maximum optical transmittance above 80%, showing a high transparency of the films in the visible region. The optical band gap was found red-shifted from 3.11 to 3.21 eV with the increase in Gd doping concentration. The increase in band gap energy from 3.14 eV to 3.16 eV was obtained for 3 at% Gd and 3 at% (Gd, Al) co-doped ZnO films. The MFM measurement proved the existence of room-temperature ferromagnetism and spin polarization in Gd and (Gd, Al) co-doped ZnO films. By co-doping with Al, the result obtained from MFM shows the enhancement of magnetic properties, as it exhibited a smaller domain size with a shorter magnetic correlation length L, a larger phase shift Φrms, and the highest value of δfrms compared to the sample with 3 at% Gd incorporated into ZnO. The carrier concentration and electrical conductivity increased with the increase in Gd concentration, whereas the electrical resistivity and hall mobility showed a reverse trend. The similar trend of results obtained for 3 at% (Gd, Al) co-doped ZnO as compared to 3 at% Gd-doped ZnO also indicates greater electrical properties after a shallow donor such as aluminum was incorporated into Gd-doped ZnO thin films. In conclusion, for future applications, one should consider the possible influence of other types of shallow donor incorporation in an attempt to enhance the properties of new types of diluted magnetic semiconductors (DMSs).

Mn-doped NiWO4 quantum dots with superior electrochemical and conductivity performance for energy storage application

Monoclinic amorphous Ni1-xMnxWO4 (x = 0.00, 0.02) compounds have been successfully synthesized by hydrothermal technique for achieving better capacitive and conductive performances. Different characterization techniques like X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible (UV–Vis) and photoluminescence (PL) spectroscopy have been employed to investigate their structural, microstructural, and optical properties. Mn-ion incorporation in the NiWO4 lattice reduces the particle size of the sample to ∼4.5 nm, compared to the pure undoped NiWO4 sample (∼18 nm), confirmed from the transmission electron microscopy image and Brunauer–Emmett–Teller analyses (BET). Tauc plot of Ni0.98Mn0.02WO4 sample exhibits a significant increase in bandgap energy, compared to pure undoped NiWO4 sample due to the quantum confinement effect. The electrochemical performance of electrodes made with these materials has been revealed by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) properties and electrochemical impedance spectroscopy (EIS). Moreover, the addition of 2 % Mn in NiWO4 causes an increase in specific surface area (117.390 m2/g) due to the reduced particle size of the material, resulting in excellent specific capacitance of 463 F g−1 at 0.5 A g−1 current density. The detailed charge storage mechanism for the improvement of conductivity and electrochemical performance of the Mn-doped NiWO4 has been revealed in different studies. An asymmetric supercapacitor device (ASC) has been fabricated using Mn-doped NiWO4 electrode material as positive electrode. The device shows superior cyclic stability upto 5000 cycles, can retain 88.4 % of its initial value.

Modification of a Z-scheme ZnO-CuO nanocomposite by Ag loading as a highly efficient visible light photocatalyst

This paper has conducted a comparative study between ZnO-CuO and ZnO-CuO-Ag nanocomposites from a characterization and photodegradation mechanism point of view. The photocatalysts with different CuO contents and Ag loadings were synthesized through a quick and convenient co-precipitation method. The microstructural analysis showed the ZnO nanorods and CuO quasi-spherical formation with uniform distribution and proper contact, while Ag induced morphological changes to aggregation of spherical nanoparticles. X-ray photoelectron spectroscopy (XPS) proved the presence of metallic Ag (Ag0) in the Ag-loaded samples. 5 mol.% Ag loading in the ZnO-7.5 mol.%CuO nanocomposite increased band gap energy from 2.85 to 2.94 eV. Significant PL (photoluminescence) intensity reduction was observed by compositing 7.5 mol.% CuO, whereas Ag loading did not cause notable change. Among various prepared nanocomposites, the ZnO-7.5 mol.%CuO with 5 mol.% Ag loading was found to be the most influential with almost complete photodegradation efficiency toward methylene blue (MB) after 90 min under visible light irradiation. Both ZnO-CuO and ZnO-CuO-Ag nanocomposites exhibited a Z-scheme mechanism for charge transfer proposed based on the radical scavenging experiments. Superoxide radicals were the main active species participating in photocatalytic reactions. The loaded Ag acted as an electron mediator and improved the charge separation efficiency in the ZnO-CuO-Ag nanocomposite. The recycling of the nanocomposite was evaluated and the results showed a reusable photocatalyst with high stability for environmental wastewater purification.

Mechanisms of nonlinear optical absorption in (GeO2)1-x–(PbF2)x (0.1 ≤ x ≤ 0.3) modified germanate glasses

The structural, optical, and nonlinear absorption properties of (GeO2)1-x–(PbF2)x (0.1 ≤ x ≤ 0.3) glasses synthesized by conventional melting and quenching technique were investigated. Bandgap energies and Urbach energies were calculated by evaluating the linear absorption spectra. The increase in the PbF2 content resulted in 0.51 eV increase in bandgap energy and 0.28 eV decrease in Urbach energy. Z-scan experiment were performed to investigate nonlinear absorption properties, and a theoretical model including the contribution of one photon absorption, two photon absorption, excited state absorption, and saturable absorption to nonlinear absorption was considered in the evaluation of the experimental data. Although the highest effective nonlinear absorption coefficient was found with the highest PbF2 content due to the smallest bandgap energy, the highest downtrend in effective nonlinear absorption coefficients was also found for highest PbF2 content due to the smallest Urbach energy.

Dye degradation, antibacterial activity and molecular docking analysis of cellulose/polyvinylpyrrolidone-doped cadmium sulphide quantum dots

In present study, control sized cadmium sulphide (CdS) quantum dots (QDs) and cellulose nanocrystals grafted polyvinylpyrrolidone (CNC-g-PVP) doped CdS QDs were synthesized via co-precipitation. The suggested pathway is fruitful in throwing out organic pollutants like methylene blue (MB) from industrial water and bactericidal applications. A series of characterization techniques were used to determine the structural, optical and morphological qualities of prepared samples. The X-ray diffraction (XRD) pattern verified hexagonal structure with no significant change occurring in the spectrum upon doping (2, 4, and 6 %). The UV–vis spectrophotometer describes blueshift in absorption pattern, resulting in an increase in band gap energy (Eg) upon doping. Catalytic activity (CA) against MB in basic and neutral medium demonstrated remarkable results compared with the acidic medium. Furthermore, bactericidal potential of doped sample (6 %) exhibited the significantly higher inhibition zones of 5.25 mm and 4.05 mm against Staphylococcus aureus (S. aureus) or Gram-positive (G+ve) and Escherichia coli (E. coli) or Gram-negative (G-ve), respectively. In silico predictions for these doped QDs were performed against selected enzyme targets (i.e. DNA gyrase and FabI) to unveil the mystery governing these bactericidal activities.

Analysis on thermal conductivity of green processed alumina nanofluid for thermal industries

The dual mechanism played by curry leaf extract on synthesis of alumina nanoparticles contributes a significant enhancement in thermal conductivity of alumina nanofluid with appreciably small volume fraction from 0.01%–0.05%. The most probable particle size of alumina nanoparticle dispersed in water of 3.12 nm observed from particle size analyser along with a strong absorption peak at λ max around 238 nm confirms the alumina nanoparticles in the fluid. The increase of energy band gap from 4.8 to 5.12 eV indicates the decrease in size of the nanoparticle solely attributed to contribution of curry leaf extraction method of preparation of nanoparticles. The spherical shaped alumina nanoparticle has got high thermal conductivity with enhancement from 1.8% to 21.44% which is attributed to the significant contribution of H-atom as energy storage unit in water. With increase of sonication time, thermal conductivity varies appreciably from 0.531 W mK−1 to 0.736 W mK−1 with volume fraction of nanofluid. Therefore, the novel combinations of characterised properties of Al2O3 nanofluid have proved to be the best thermally stable heat transfer fluid compared to conventional cooling fluids.

Enhanced Photocatalytic Activity of Zn-Al Layered Double Hydroxides for Methyl Violet and Peat Water Photooxidation.

Zn-Al Layered Double Hydroxides (Zn-Al LDHs) and its calcined form were successfully prepared and utilized for the removal of methyl violet (MV) and treatment of peat water by photocatalytic oxidation. The research was aimed to evaluate the effect of calcination to Zn-Al LDHs for the effect on the physicochemical character and the capability as a photocatalyst. The characterization of the samples was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmet–Teller specific surface area (BET), and X-ray photoelectron spectroscopy (XPS). The results showed that the increased BET specific surface area along with the enhanced porous structure was achieved by the calcination procedure, which is associated with the enhanced interlayer space of d003 identified by XRD analysis. Thermal conversion showed an influence to the increased band gap energy from 3.10 eV in the uncalcined Zn-Al LDHs into 3.16 eV for the calcined material. These character changes contributed to the enhanced photocatalytic activity of the Zn-AL LDHs by calcination, which was proposed and verified by experiments. It was observed that photocatalytic activity of the material for MV gave about a 45.57% removal of MV and a 68% removal for the natural organic material of the peat water.

Effect of Zr content on the wetting of BaTi1−xZrxO3 perovskite ceramics by Ag-based liquids

The study of the contact characteristics between functional ceramics and potential electrode metals is of primary importance when developing new devices. BaTiO3 is the most used dielectric ceramic and its functional properties are tailored by the introduction of substituents. In this work, we verify the effect of the zirconium substituents in BaTi1−xZrxO3 (x = 0, 0.1, 0.2, 0.4) ferroelectric perovskites on the wettability by liquid Ag and Ag-3 at% Cu alloy at 1000 °C in air, and the obtained metal/ceramic interfaces are characterised.With x going from 0 to 0.4, the contact angles increase from 83° to 104° and from 46° to 72° for pure Ag and Ag-3 at% Cu respectively. This trend is in agreement with the increased band-gap energy of the perovskites ascribed to the increase of Zr content. The better wetting of Ag-3 at% Cu compared to pure Ag is due to the formation of interfacial CuO; no further interfacial phenomena nor mutual interdiffusion are detected.

Nanomaterials For Hydrogen Generation: A Review

Hydrogen is proving its potential as most appealing and eco friendly energy fuels. Theorganic reforming based nano-sized composites and nanocatalyst for photocatalytic water splitting applications are attracting growing interest in the prospect of hydrogen generation from solar energy with minimal environmental impact. Because of the higher surface area and sizedependent features, such as increased absorption coefficient,reduced carrier-scattering rate and increased band-gap energy, the nano- semiconductors have potential advantages in PEC applications when compared to bulk materials. Despite recent research in producing materials having high specific photoactivity, the conversion efficiencies from solar-to-hydrogen are still far from achieving the basic requirements for actual solar applications, according to a literature review. The paper begins by providing an overview of the conventional hydrogen generation techniques. This paper also examines current advances and challenges in water splitting methods based on Photo Electro Chemistry based nanomaterials and various ways for improving hydrogen evolution.

Tailoring the electronic, optical and mechanical properties of KMgH3 and RbCaH3 perovskite hydrides without and with Samarium

Perovskite hydrides such as KMgH3 and RbCaH3 have been proven to be an attractive candidate for good application prospects in optoelectronic devices and conversion energy. Doping these perovskites with rare earth has turned into a progressively essential way to improve luminescence and photo-conversion of devices. In this work, the ab-initio calculations have been carried out to explore the structural, electronic, optical, and mechanical properties of both KMgH3 and RbCaH3 without and with Sm based on generalized gradient approximation functional within the framework of DFT including the spin−orbit coupling. It is found that doping the perovskites with Sm depicts substantially modification in electronic behavior leading increased bandgap energy as well as the carrier effective masses with increasing Sm concentrations for the case of KMgH3, while it has been reduced for RbCaH3. In addition, the optical investigation reveals a blue-shift phenomenon from absorption coefficient spectra, which is owing to the Sm doping into KMgH3; combined with a minimum absorption in visible spectrum for pure KMgH3 perovskite. Besides, we denote a maximum absorption in the UV region of the doped RbCaH3. Furthermore, the mechanical analysis exhibits that these perovskites are hard and stiffer, especially KMgH3 hydride systems. These outcomes may conduct and give a reliable reference for experimenters to design novel perovskite hydrides toward improving optoelectronic performances.

Tuning the structural, morphological and optical properties of Sr-doped BFO thin films

ABSTRACT The effect of strontium (Sr) doping on structural, morphological and optical properties of bismuth ferrite (BFO) thin films containing various doping concentrations of Bi(1−a)Sr a FeO3 (a = 0.00, 0.01, 0.03, 0.05, 0.10) was synthesized using a spray pyrolysis technique. Based on the experimental results, EDAX confirmed the existence of bismuth, ferrous and strontium particles in the developed thin films. The XRD results confirmed a decrease in the size of the crystals after Sr substitution at Bi site. The FESEM results confirmed the reduction of particle size with dopant addition. The BFO films exhibited a cone-type grain growth with an increase in surface roughness with Sr dopant. The results obtained from UV–Vis spectrophotometer show an increase in energy bandgap for various concentrations of the dopant. The results obtained from the characterization revealed that Sr-doped BFO is a very good candidate for gas sensor applications.

Using femtosecond laser pulses to investigate the nonlinear optical properties of silver nanoparticles colloids in distilled water synthesized by laser ablation

The nonlinear optical properties of silver nanoparticles (AgNPs) colloids in distilled water, when irradiated with 100 fs laser pulses, were investigated experimentally using the Z-scan technique. At a constant wavelength of 760 nm and different excitation powers, the nonlinear absorption coefficient and nonlinear refractive index were measured. The AgNPs colloids are synthesized by laser ablation of silver bulk in distilled water using a 532 nm Nd: YAG laser with different ablation energies fluence of 9, 15.5, and 26 ⨯104 (J/cm2) over a 30min ablation time. The nanoparticle size, shape, and absorption spectra of nanoparticle colloids were determined using transmission electron microscopy and an ultraviolet–visible spectrophotometer. Spherical AgNPs are formed with an average diameter ranging from 7.5 to 12 nm. As the laser ablation energy fluence increases, the average size of the AgNPs decreases while the bandgap energy increases. As the excitation laser power and AgNPs size increase, the nonlinear absorption coefficient and nonlinear refractive index decrease. The optical limiting performance of AgNPs improves with increasing laser ablation energy fluence, with the best performance at 26⨯104 (J/cm2).

Efficient photocatalytic degradation of industrial contaminants by Piper longum mediated ZnO nanoparticles

Piper longum extract as a reducing agent in green synthesis method is used to synthesize ZnO nanoparticles (ZnO-NPs). The impact of the reductant on the structural, optical and surface morphological properties of ZnO-NPs can be analyzed. Piper longum extract has delicately tuned the band gap of ZnO-NPs. Increase in energy band gap indicates an increase in the number of capping molecules in the prepared ZnO nanoparticles. The carbohydrates and proteins not only play a fundamental role in ZnO capping, which is important for its stability, determination and biocompatibility. Thus obtained nanosized ZnO particles are confirmed by the surface morphological studies. Because of various surface interface properties might have different physical-chemical, desorption–adsorption abilities in the direction towards microbes, create different antibacterial performances. S.aureus has maximum inhibition zone of 23 mm and Escherichia coli has minimum inhibition zone of 7 mm. To assess the photocatalytic activity of the prepared ZnO-NPs under UV light irradiation, methyl orange, malachite green and methylene blue dyes were utilized as model contaminants. The degradation efficiency of MG, MB and MO dyes solution is found that 96%, 69% and 48% of degradation efficiency respectively under ultraviolet light irradiation. The properties of synthetic nanopowders suggest that they have important potential for a variety of biochemical and environmental applications.

Hydrolysis Temperature dependent Structural, Optical Band Gap and the associated Urbach Tail Energy of Cellulose Nanocrystals Fabricated from Water Hyacinth

This study has thus systematically investigated the fingerprints of hydrolysis temperature on the optical and structural properties of the resultant CNCs. From the study, it was observed that increase in hydrolysis temperature decreases the grain size from ~21.7 nm to ~19.3 nm. However, crystallinity increased from 57.9% to 60.3% as calculated using Scherrer equation. By performing UV-Vis spectroscopy, the value of the peak wavelength for maximum absorption, Xc increased from ~247.52 nm for 50oC to ~247.76 for 90oC. The value of FWHM equally increased from ~12.17 nm for 50oC to ~13.48 nm for 90oC. Additionally, increasing hydrolysis temperature from 50oC to 90oC decreased the bandgap energy, Eg from ~ 5.31 eV to ~5.14 eV. However, the Urbach energy increased from ~116 meV to ~217 meV respectively. From a plot of Eg verses Eu, the optical band gap energy of the CNCs when there is no disorder in their microstructure was found to be ~5.43 eV. The CNCs have zero optical band gap energy when hydrolysis is done at ~1297.6oC. Further, we have shown that the Urbach energy is absent when hydrolysis is done at 14.23oC. This is the energy when the localized defect states in an optical band gap region are completely screened. The hydrolysis temperature dependent increase in the electronic disorder in the crystal (Urbarch energy) with increase in associated band gap energy has thus been estimated to account for the optical disorder in the CNCs. &nbsp;