Saurabh Dalela
@uok.ac.in
Professor, Department of Physics
University of Kota
RESEARCH INTERESTS
Materials Sciences, Superconductivity, Dilute Magnetic Semiconductors, Structural, Optical, Magnetic and Electronic Structure Properties: X ray Absorption Spectroscopy and X ray Photoelectron Spectroscopy.
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Swati Soni, K. Kabra, Jyoti Sahu, Divya Prakash Dubey, B. Dalela, P.A. Alvi, Shalendra Kumar, M. Gupta, and S. Dalela
Elsevier BV
N.S. Leel, M. Kiran, P.A. Alvi, B. Dalela, Shalendra Kumar, and S. Dalela
Elsevier BV
S.B. Dangi, N.S. Leel, A.M. Quraishi, S.Z. Hashmi, Shalendra Kumar, Saurabh Dalela, Jasgurpreet Singh, B.L. Choudhary, M. Ayaz Ahmad, and P.A. Alvi
Elsevier BV
Jyoti Arya, Narendra S. Leel, Aakansha, Abdul Mosawir Quraishi, Sonia Zeba Hashmi, Shalendra Kumar, Banwari Lal Choudhary, Saurabh Dalela, Zafrul Hasan, Jasgurpreet Singh,et al.
Wiley
Motivated from the extraordinary properties of CeO2 nanomaterial, this article is directed toward the synthesis of recyclable polyvinyl alcohol–CeO2 polymer nanocomposite with variable wt% of CeO2 and investigating their improvements in structural, electrical, optical, and surface properties. The crystalline size and micro‐strain are measured using X‐ray diffraction (XRD) data. Ultraviolet–visible–near‐infrared spectrophotometer is used to study the optical characteristics. Absorbance with redshift is found to enhance; while optical bandgap is reduced from 2.51 to 2.36 eV on increasing wt% of CeO2 nanofiller. The mechanism of reduction in bandgap is supported by the XRD analysis. Refractive index is found to vary from 2.54 to 2.59 and the range of Urbach energy varies from 1.19 to 0.42 eV on increasing the amount of nanofillers. Surface morphology, dielectric constant, and electrical conductivity are also found to improve with increasing wt% of nanofiller. The dielectric constant is improved from 60 to 120 at 1.5 Hz. The rise in conductivity with increasing wt% of CeO2 and rising frequency is due to the enhancement of mobility of the charge carriers and ionic hopping mechanism in conduction process. Characterization outcomes suggest that the prepared composites can be claimed as useful in fabricating the flexible optoelectronic devices.
Vimala Dhayal, Narendra Singh Leel, Prince Mufti Ziaul Hasan, Reem Darwesh, Abdul Mosawir Quraishi, Sonia Zeba Hashmi, Shalendra Kumar, Saurabh Dalela, Jasgurpreet Singh, and Parvez Ahmad Alvi
Wiley
The study herein is directed toward the tuning of various properties of recyclable and biocompatible polymer: chitosan (CS) via incorporating the variable wt% of r‐GO in the polymer. The CS/r‐GO polymer nanocomposites (PNCs) are prepared in the form of free‐standing film by solution mixing and casting technique. To search the potential applications, the prepared PNCs are characterized in terms of structural, photoluminescence (PL), surface morphology, optical, and Raman spectra. The crystalline size and microstrain both are enhanced with rise in wt% of r‐GO nanofiller. Raman spectra confirm that as the wt% of r‐GO increases, there is a minor shift toward a smaller wavenumber in the locations of the D, G, and 2D bands, while the intensity ratios ) increase. Field‐emission scanning electron microscopy results are capable of offering details regarding the surface quality for the interface purposes. The characteristic peaks and their broadening in PL spectra, chromaticity coordinates, dominant wavelength, and correlated color temperature are altered with variation of r‐GO wt.%. The optical bandgap, refractive index, and Urbach energy are found to tune with varying the nanofiller wt.%. These results suggest that CS/r‐GO PNC may be the potential candidate for possible application in fabricating the tunable optoelectronic devices.
Garima Srivastava, Shalendra Kumar, S. Z. Hashmi, Ravina, A. M. Quraishi, Saurabh Dalela, Faheem Ahmed, Kavita Kumari, B. H. Koo, and P. A. Alvi
Springer Science and Business Media LLC
P.M.Z. Hasan, Shivratan Saini, A.A. Melaibari, N.S. Leel, Aakansha, Reem Darwesh, A.M. Quraishi, Jasgurpreet Singh, A.E. Kuznetsov, S.Z. Hashmi,et al.
Elsevier BV
H.R. Khakhal, Sudhish Kumar, D. Patidar, Shalendra Kumar, V.S. Vats, B. Dalela, P.A. Alvi, N.S. Leel, and S. Dalela
Elsevier BV
N.S. Leel, M. Kiran, M.K. Kumawat, P.A. Alvi, V.S. Vats, D. Patidar, B. Dalela, Shalendra Kumar, and S. Dalela
Elsevier BV
H. R. Khakhal, Sudhish Kumar, S. N. Dolia, V. S. Vats, B. Dalela, P. A. Alvi, Shalendra Kumar, and S. Dalela
World Scientific Pub Co Pte Ltd
Ce[Formula: see text]Pr[Formula: see text]O2 ([Formula: see text], 0.02, 0.04, 0.06, and 0.08) nano-materials synthesized using co-precipitation method have been investigated mainly for electronic structure properties in this manuscript. Findings and supporting studies are presented to understand the role of valence states of host and dopant cations information of F[Formula: see text] centers through X-ray photoelectron spectroscopy (XPS). Sustained cubic fluorite system confirmed by X-ray diffraction (XRD) analysis and red-shifting of energy gap by UV–Vis spectroscopy in all the samples are our findings. Samples further implored by XPS indicate incidence of cerium and Pr cations in both the oxidation states of 4[Formula: see text] and 3[Formula: see text], respectively. Finally, it has been observed that optical, electronic structure and magnetic properties of CeO2 nanomaterials can be modified by Pr-doping, promising better yield samples with good amount of ferromagnetism for potential uses in the technological applications like spintronics, optoelectronics, and photocatalytic.
Shyam Sunder Sharma, Khushboo Sharma, Jyoti Sahu, Jaymin Ray, Saral Kumar Gupta, and Saurabh Dalela
Springer Science and Business Media LLC
Shalendra Kumar, Faheem Ahmed, Nagih M. Shaalan, Nishat Arshi, Saurabh Dalela, and Keun Hwa Chae
MDPI AG
ZnO is a potential candidate for providing an economic and environmentally friendly substitute for energy storage materials. Therefore, in this work, Fe-doped ZnO nanostructures prepared using the microwave irradiation procedure were investigated for structural, morphological, magnetic, electronic structural, specific surface area and electrochemical properties to be used as electrodes for supercapacitors. The X-ray diffraction, high-resolution transmission electron microscopy images, and selective-area electron diffraction pattern indicated that the nanocrystalline structures of Fe-doped ZnO were found to possess a hexagonal wurtzite structure. The effect of Fe doping in the ZnO matrix was observed on the lattice parameters, which were found to increase with the dopant concentration. Rods and a nanosheet-like morphology were observed via FESEM images. The ferromagnetic nature of samples is associated with the presence of bound magnetic polarons. The enhancement of saturation magnetization was observed due to Fe doping up to 3% in correspondence with the increase in the number of bound magnetic polarons with an Fe content of up to 3%. This behavior is observed as a result of the change in the oxidation state from +2 to +3, which was a consequence of Fe doping ranging from 3% to 5%. The electrode performance of Fe-doped ZnO nanostructures was studied using electrochemical measurements. The cyclic voltammetry (CV) results inferred that the specific capacitance increased with Fe doping and displayed a high specific capacitance of 286 F·g−1 at 10 mV/s for 3% Fe-doped ZnO nanostructures and decreased beyond that. Furthermore, the stability of the Zn0.97Fe0.03O electrode, which was examined by performing 2000 cycles, showed excellent cyclic stability (85.0% of value retained up to 2000 cycles) with the highest specific capacitance of 276.4 F·g−1, signifying its appropriateness as an electrode for energy storage applications.
Nagih M. Shaalan, Shalendra Kumar, Faheem Ahmed, Nishat Arshi, Saurabh Dalela, and Keun Hwa Chae
MDPI AG
Herein, we have reported a novel strategy for improving the electrochemical performance of laser-induced graphene (LIG) supercapacitors (SCs). The LIG was prepared using a CO2 laser system. The polyimide polymer was the source material for the fabrication of the LIG. The doping process was performed in situ using the CO2 laser, which works as a rapid thermal treatment to combine graphene and NiO particles. NiO was used to improve the capacitance of graphene by combining an electric double-layer capacitor (EDLC) with the pseudo-capacitance effect. The high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, and Raman spectroscopy showed that the structure of the LIG is multilayered and waved. The HRTEM image proves the distribution of NiO fine particles with sizes of 5–10 nm into the graphene layers. The electrochemical performance of the as-prepared LIG was tested. The effect of the combination of the two materials (oxide and carbon) was investigated at different concentrations. The LIG showed a specific capacitance of 69 Fg−1, which increased up to 174 Fg−1 for the NiO-doped LIG. The stability investigations showed that the electrodes were very stable for more than 1000 cycles. This current study establishes an innovative method to improve the electrochemical properties of LIG.
Faheem Ahmed, Shalendra Kumar, Nagih M. Shaalan, Nishat Arshi, Saurabh Dalela, and Keun Hwa Chae
MDPI AG
To meet the growing demand for efficient and sustainable power sources, it is crucial to develop high-performance energy storage systems. Additionally, they should be cost-effective and able to operate without any detrimental environmental side effects. In this study, rice husk-activated carbon (RHAC), which is known for its abundance, low cost, and excellent electrochemical performance, was combined with MnFe2O4 nanostructures to improve the overall capacitance of asymmetric supercapacitors (ASCs) and their energy density. A series of activation and carbonization steps are involved in the fabrication process for RHAC from rice husk. Furthermore, the BET surface area for RHAC was determined to be 980 m2 g−1 and superior porosities (average pore diameter of 7.2 nm) provide abundant active sites for charge storage. Additionally, MnFe2O4 nanostructures were effective pseudocapacitive electrode materials due to their combined Faradic and non-Faradic capacitances. In order to assess the electrochemical performance of ASCs extensively, several characterization techniques were employed, including galvanostatic charge –discharge, cyclic voltammetry, and electrochemical impedance spectroscopy. Comparatively, the ASC demonstrated a maximum specific capacitance of ~420 F/g at a current density of 0.5 A/g. The as-fabricated ASC possesses remarkable electrochemical characteristics, including high specific capacitance, superior rate capability, and long-term cycle stability. The developed asymmetric configuration retained 98% of its capacitance even after 12,000 cycles performed at a current density of 6A/g, demonstrating its stability and reliability for supercapacitors. The present study demonstrates the potential of synergistic combinations of RHAC and MnFe2O4 nanostructures in improving supercapacitor performance, as well as providing a sustainable method of using agricultural waste for energy storage.
Shalendra Kumar, Faheem Ahmed, Nagih M. Shaalan, Nishat Arshi, Saurabh Dalela, and Keun Hwa Chae
MDPI AG
Magnetic nanoparticles of NiFe2O4 were successfully prepared by utilizing the sol–gel techniques. The prepared samples were investigated through various techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), dielectric spectroscopy, DC magnetization and electrochemical measurements. XRD data analysed using Rietveld refinement procedure inferred that NiFe2O4 nanoparticles displayed a single-phase nature with face-centred cubic crystallinity with space group Fd-3m. Average crystallite size estimated using the XRD patterns was observed to be ~10 nm. The ring pattern observed in the selected area electron diffraction pattern (SAED) also confirmed the single-phase formation in NiFe2O4 nanoparticles. TEM micrographs confirmed the uniformly distributed nanoparticles with spherical shape and an average particle size of 9.7 nm. Raman spectroscopy showed characteristic bands corresponding to NiFe2O4 with a shift of the A1g mode, which may be due to possible development of oxygen vacancies. Dielectric constant, measured at different temperatures, increased with temperature and decreased with increase in frequency at all temperatures. The Havrilliak–Negami model used to study the dielectric spectroscopy indicated that a NiFe2O4 nanoparticles display non-Debye type relaxation. Jonscher’s power law was utilized for the calculation of the exponent and DC conductivity. The exponent values clearly demonstrated the non-ohmic behaviour of NiFe2O4 nanoparticles. The dielectric constant of the nanoparticles was found to be >300, showing a normal dispersive behaviour. AC conductivity showed an increase with the rise in temperature with the highest value of 3.4 × 10−9 S/cm at 323 K. The M-H curves revealed the ferromagnetic behaviour of a NiFe2O4 nanoparticle. The ZFC and FC studies suggested a blocking temperature of ~64 K. The saturation of magnetization determined using the law of approach to saturation was ~61.4 emu/g at 10 K, corresponding to the magnetic anisotropy ~2.9 × 104 erg/cm3. Electrochemical studies showed that a specific capacitance of ~600 F g−1 was observed from the cyclic voltammetry and galvanostatic charge–discharge, which suggested its utilization as a potential electrode for supercapacitor applications.
Anju Kumari, Kavita Kumari, Rezq Naji Aljawfi, P. A. Alvi, Saurabh Dalela, Mohamad M. Ahmad, Amit Kumar Chawla, Rajesh Kumar, Ankush Vij, and Shalendra Kumar
Springer Science and Business Media LLC
Ravina, Shalendra Kumar, S. Z. Hashmi, Garima Srivastava, Jasgurpreet Singh, A. M. Quraishi, Saurabh Dalela, Faheem Ahmed, and P. A. Alvi
Springer Science and Business Media LLC
Shalendra Kumar, Faheem Ahmed, Nagih M. Shaalan, Nishat Arshi, Saurabh Dalela, and Keun H. Chae
MDPI AG
CeXO2 (X: Fe, Mn) nanoparticles, synthesized using the coprecipitation route, were investigated for their structural, morphological, magnetic, and electrochemical properties using X-ray diffraction (XRD), field emission transmission electron microscopy (FE-TEM), dc magnetization, and cyclic voltammetry methods. The single-phase formation of CeO2 nanoparticles with FCC fluorite structure was confirmed by the Rietveld refinement, indicating the successful incorporation of Fe and Mn in the CeO2 matrix with the reduced dimensions and band gap values. The Raman analysis supported the lowest band gap of Fe-doped CeO2 on account of oxygen non-stoichiometry. The samples exhibited weak room temperature ferromagnetism, which was found to be enhanced in the Fe doped CeO2. The NEXAFS analysis supported the results by revealing the oxidation state of Fe to be Fe2+/Fe3+ in Fe-doped CeO2 nanoparticles. Further, the room temperature electrochemical performance of CeXO2 (X: Fe, Mn) nanoparticles was measured with a scan rate of 10 mV s−1 using 1 M KCL electrolyte, which showed that the Ce0.95Fe0.05O2 electrode revealed excellent performance with a specific capacitance of 945 Fּ·g−1 for the application in energy storage devices.
J. Sahu, Shalendra Kumar, Faheem Ahmed, P.A. Alvi, B. Dalela, D.M. Phase, M. Gupta, and S. Dalela
Elsevier BV
N.L. Heda, Kishor Kumar, Vinit Sharma, Ushma Ahuja, S. Dalela, and B.L. Ahuja
Elsevier BV
Shalendra Kumar, Kavita Kumari, Akshay Kumar, B.H. Koo, Rajesh Kumar, P.A. Alvi, and Saurabh Dalela
Elsevier
Kavita Kumari, Akshay Kumar, Rajesh Kumar, B.H. Koo, Saurabh Dalela, P.A. Alvi, Mohd. Hashim, and Shalendra Kumar
Elsevier
Garima Srivastava, Saurabh Dalela, Shalendra Kumar, B.L. Choudhary, and P.A. Alvi
Elsevier BV
Ravina, Saurabh Dalela, Shalendra Kumar, B.L. Choudhary, and P.A. Alvi
Elsevier BV
Richa Dolia, A. M. Quraishi, Sandhya Kattayat, Smitha Josey, Saurabh Dalela, Mohammed Ezzeldien, and P. A. Alvi
Springer Science and Business Media LLC