Rajesh Kumar

• Ph.D. (Physics)
• Indian Institute of Technology Indore

In the present study, we investigated biochemical, hematological, lipidomic, and metabolomic alterations associated with different SAR-CoV-2 variants of concern (VOCs), such as WT, α, β, γ, and δ, as well as their impact on COVID-19 severity. Across the first and second waves in India, a machine learning approach was used in 3134 COVID-19 patients,...

Designing materials in an appropriate (nano-) architecture could prove to be an effective strategy to improve several electrochemical properties to yield high-energy storage devices for their practical applications. Here, a...

A non-linear temperature dependent Fano resonance in V2O5 micro-crystallites is discovered which also is found being dictated by the laser flux. A Gaussian temperature dependent Fano parameter is observed and...

Understanding electron-phonon (Fano) interactions, by employing techniques like Raman spectroscopy, in materials proves important in designing them for appropriate optoelectronic applications and extracting optimized performance. Orthorhombic vanadium pentoxide (V2O5) micro crystallites’ B1g/B3g mode around 702 cm⁻¹ has been investigated to establi...

A facile in situ method of the liquid/liquid (L/L) polymerization strategy for synthesizing silver‐doped hollandite manganese oxide (Ag‐HMO) on polypyrrole (PPy) support is reported for the first time. The highly innovative synthetic method involves producing α‐MnO2 attached to PPy oligomers under low‐temperature conditions. Subsequently, Ag⁺ ions...

Pursuing the development of eco‐friendly, cost‐effective and flexible materials that offer high‐color contrast and low power consumption is a promising approach for advancing the next‐generation optoelectronic devices. Herein, we report the synthesis of a heteroleptic copper(I) complex [Xantphos‐Cu‐cmdf]PF6 (C1), in high yield, using Xantphos and c...

The rapid technological advancement in portable devices forces rising demand for novel materials and fabrication paradigms for developing electronic devices into a wearable gadget with no exception to supercapacitors, widely...

Liquid-to-solid-like phase transition (LSPT) of disordered proteins via metastable liquid-like droplets is a well-documented phenomenon in biology and linked to many pathological conditions including neurodegenerative diseases. However, very less is known about the early microscopic events and transient intermediates involved in the irreversible pr...

An all‐organic multifunctional solid‐state electrochromic supercapacitor has been designed by utilizing 2D‐MXene and a combination of viologen and polythiophene. The 2D MXene is synthesized using selective etching method and properly characterized; afterward, it is doped in ethyl viologen (EV) and a solid‐state electrochromic supercapacitor device...

Respiratory humidity sensors are essential for monitoring breath conditions in a variety of applications such as respiratory disease diagnosis, sleep apnea screening, and personalized medicine. With the increasing prevalence of respiratory diseases, such as asthma, chronic obstructive pulmonary disease (COPD), and sleep apnea, they have become esse...

Hydrogen as a clean fuel is increasingly sought after for its potential to replace non-renewable energy sources, with the hydrogen evolution reaction (HER) presenting a sustainable method for its production. This study focuses on enhancing HER efficiency through the fabrication of a Z-scheme based tungsten di sulfide/titanium di oxide (WS2/TiO2) he...

Novel resistive copper PCB-based sensors have been developed for room temperature NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> gas detection at a concentration as low as 10 parts per million (ppm), employing a binary hybrid composition of Molybdenum Disulfide (MoS <sub xmlns:mml="http://w...

Narrow color spectrum is a major limitation of the conventional electrochromic devices (ECDs) having a single electrochromic polymer (ECP) layer. Here, we report the design and fabrication of dual ECD capable of displaying a broader color spectrum at different voltages. The ECD color depends on the energy band gap of the ECP layer. Thus, it is poss...

Spectroscopic techniques, especially Raman spectroscopy, cover a large subset in the teaching and research domain of physical chemistry. Raman spectroscopy, and other Raman based techniques, establishes itself as a powerful analytical tool with diverse applications across scientific, industrial, and natural science (including biology and pharmacy)...

Electrochemically deposited thin films yield high uniformity, a property which is quite vital to in the context of electrochromic (EC) coatings and devices. Tungsten oxide and polyaniline are two such materials that show superior EC properties individually. However, when combined into a solid‐state device structure, they yield a device where the ef...

Habitual consumption of areca/betel nut in Southeast Asia has been associated with oral submucous fibrosis (OSMF) and its malignant transformation to oral squamous cell carcinoma. The current study aimed to assess the molecular alterations in fibroblast cell lines after treatment with areca nut. Areca nut extract (ANE) was prepared and characterize...

Inclusion of charge storage properties to electrochromic devices has gained much interest and has evolved into a promising emerging energy related field due to multifunctional smart device application. Here, an organic-inorganic solid state asymmetric electrochromic supercapacitor device (ESCD) containing nano-CoTiO3 mixed poly-3-hexylthiophene (P3...

The systematic structure modification of metal oxides is becoming more attractive, and effective strategies for structural tunning are highly desirable for improving their practical color‐modulating energy storage performances. Here, the ability of a stoichiometrically tuned oxide‐hydroxide complex of porous vanadium oxide, namely [V2O2+ξ(OH)3‐ξ]ξ...

Helicobacter pylori and Epstein-Barr Virus (EBV) are Group 1 carcinogens that can enhance gastric cancer progression. Bioactive substances extracted from plants can be effective therapeutic agents in cancer treatment. For example, Withania somnifera extract-WSE reduces the Gankyrin oncoprotein, which is upregulated in the presence of H. pylori and...

We propose facile synthesis of POM-GMP supramolecular hydrogel exhibiting chromism in response to multiple stimuli-light, electricity, temperature, stress, iodide, pH and biologically relevant thiols such as cysteine and glutathione.

Using hybrids and photon illumination together is an important step toward making high-performance gas sensors. Hybrid materials have their own properties that can improve the way gas sensors work, and photon illumination can make the sensor more sensitive. There is currently a lack of understanding regarding the impact of photoassisted gas sensing...

Background EBV infection has long been postulated to trigger multiple sclerosis (MS) and anti-EBV antibodies showed a consistent presence in MS patients. Previous reports from our group have shown that the EBV infects different brain cells. Entry of the virus in neuronal cells is assisted by several host factors including membrane cholesterol. By u...

Two‐dimensional (2D) tungsten disulphide (WS2) based heterostructures with modified interfaces have huge potential for photocatalytic applications. Integrating WS2 with one‐dimensional (1D) titanium dioxide (TiO2) and 2D molybdenum disulphide (MoS2) structures to form heterostructures, enhances its photocatalytic activity. The enrichment in photoca...

Exploring materials and device paradigms for multifunctional electrochemical applications such as supercapacitors and sensing makes materials more suitable for real-life applications. In this study, microcrystalline MoO3 powder has been synthesized using a simple sol–gel method, and its suitability for energy storage devices and HF sensing performa...

Protein aggregation and inactivation upon surface immobilization are major limiting factors for analytical applications in biotechnology-related fields. Protein immobilization on solid surfaces often requires multi-step surface passivation, which is time-consuming and inefficient. Herein, we have discovered that biomolecular condensates of biologic...

A method to tune the electrochemical energy storage properties of molybdenum disulfide (MoS2) nanoflowers has been explored. The MoS2 nanoflowers were synthesized by solution based hydrothermal route using ammonium heptamolybdate tetrahydrate (AHM) and thiourea (TU) at 220 ℃. X-ray diffraction and Raman spectroscopy indicated the formation of 2H-ph...

In the quest to create effective sensors that operate at room temperature, consume less power and maintain their stability over time for detecting toxic gases in the environment, molybdenum disulfide (MoS2) and MoS2-based hybrids have emerged as potent materials. In this context, the current work describes the fabrication of Au-MoS2 hybrid gas sens...

Herbal electronics” is a very new term tossed for the area where optical and electrical properties of herbal materials are being studied for possible application in electronics. The optical properties of extract solutions obtained from two raw materials namely turmeric, and henna has been studied here using absorption and luminescence spectroscopie...

Electrochromism, a well‐defined phenomenon of bias‐induced reversible color switching, has led to real applications in several smart devices including smart windows and self‐powered batteries and solar panels. For these applications, the electrochromic (EC) materials need to be integrated as solid‐state devices. Deciphering ways to recreate a conve...

Lead based hybrid organic-inorganic halide perovskite (LHP) possess extraordinary optical, electronic and structural properties. A simple perovskite formed by the cation (MA⁺) with anion (I⁻ and Br⁻) enhance efficacy of catalytic reaction towards organic pollutant or more specifically dye degradation. This study focuses on a comparative photo-elect...

Among transition metal dichalcogenides, molybdenum disulfide (MoS2) is considered as the most cost-effective electrode material for energy storage applications such as supercapacitors and supercapatteries. The layered morphology, intrinsic high surface area and edge sites favour the enhanced energy storage performance of MoS2 nanostructures. Low-co...

Alternate methods for deposition of electrochromic metal oxide thin films need to be explored to obtain an optimized one while designing solid state hybrid or all-inorganic electrochromic device. To continue this quest, electrochromic performance from a hybrid electrochromic device obtaining using plasma assisted atomic layer deposition (ALD) grown...

An organic–inorganic hybrid electrochromic device was fabricated by combining the films of hydrothermally synthesized tungsten oxide (WO 3 ) with electrodeposited polypyrrole. Before making a device, these deposited thin films were characterized using scanning electron microscopy, infrared spectroscopy, and Raman spectroscopy techniques. Thereafter...

A new methodology to enhance electrochromic performance and making it multifunctional ready has been demonstrated where an all-organic solid state electrochromic device has been made to display dual band color...

Fabricating energy storage devices in different paradigms makes them more relevant from application point of view. Flexible supercapacitors with great specific capacitance retention with maximum possible bending angles and high...

This article presents the photo-catalytic dye-degradation from pure and doped multi-component Ge17Sb8Se75-xErx(x = 0, 0.2, 0.4, 0.6, 0.8, 1) chalcogenides system has been established in visible light (orange ∼590 nm) for the first time. Band-gap shifting, suitable band position and higher absorption of visible range radiation have been accounted fo...

Search for a versatile flexible all‐organic liquid electrolyte‐less solid–state electrochromic device continues. In this quest, a polyaniline‐Viologen‐(PANI‐EV)‐based electrochromic device has been reported and designed based on the complementary redox behavior and easy processibility. Electrochromic electrodes are first individually characterized...

For the first time, simple and robust melt quench synthesis based pure and doped quaternary Ge17Sb8Se75-xErx(Er; x = 0, 0.6, 1) chalcogenides have been demonstrated under green light (560 nm) illumination photo-catalytic dye degradation. Inspired by the excellent optoelectronic and thermal properties of studied composition, further, rare earth elem...

The complete analysis of structural transformation and defects in a disordered structure like graphene oxide (GO) is very important as it will be supportive in fine-tuning of its intrinsic properties and further expanding their potential application in diverse fields. Herein, the first order Raman scattering has been employed to study the structura...

Simpler methods for fabricating electrodes for charge storage applications are required because electrode materials have appreciable significance to enhance the electrochemical performance of charge/energy storage devices. Fractal porous silicon (pSi) substrate, prepared using a simple metal-assisted chemical etching (MACE) technique, has been stud...

2D/1D-MoS2/TiO2 heterostructures have proven to be vigorous for photocatalytic applications. The enhancement in photocatalytic activity of heterostructures may get influenced by the accumulation of strain at the interface that affects the interfacial interaction. Keeping that in view, present paper reports the strain accumulated interfacial modific...

Methods to improve the performance of solid state electrochromic devices (ECDs) need to be explored and the dynamic doping process must be optimized to achieve ideal device performance. Molybdenum disulphide (MoS 2 ) doped ECD has been fabricated by using two conducting polymeric films, i.e. polythiophene (P3HT) and ethyl viologen (EV), to investig...

The brain microvascular endothelial cells (ECs) play an important role in protecting the brain from hazardous pathogens. However, some viral pathogens can smartly modulate the endothelial pathways to gain entry inside the brain. Further, these viruses can cause endothelial dysfunction which could develop serious neurological ailments. Epstein-Barr...

An inclusive approach for analysing size dependent field emission properties of silicon nanowires has been presented in the current study. The proposed framework complements the traditionally used method of analysis (using Fowler-Nordheim framework) which takes care of the tunnelling current corresponding to low as well as high electric fields. The...

Inorganic oxide electrochromic electrodes can be made more robust by adopting suitable deposition techniques. Electrochemically deposited Tungsten Oxide (WO3) film through chronoamperometry has been studied here for application as electrochromic auxiliary electrode. Thoroughly characterized film using electron microscopy, X-ray diffraction and Rama...

A nonlinear Fano interaction has been reported here which is manifest in terms of a parabolic temperature-dependent phonon decay process observable in terms of a Raman spectral parameter. Temperature-dependent Raman spectroscopic studies have been carried out on heavily and moderately doped crystalline silicon to investigate the behavior of anharmo...

Excitation wavelength-dependent Raman spectroscopy has been carried out to study electron-phonon interaction (Fano resonance) in multi-layered bulk 2H-MoS2 nano-flakes. The electron-phonon coupling is proposed to be caused due to interaction between energy of an excitonic quasi-electronic continuum and the discrete one phonon, first-order Raman mod...

Исследован процесс формирования тонких пленок системы Ni–Mn–O методом молекулярного наслаи- вания при эквивалентном напуске металлоорганических реагентов. В качестве исходных реагентов использовались бис(циклопентадиенил)никеля (NiCp2) и трис(2,2,6,6-тетраметил-3,5-гептандионато)- марганца(III) [Mn(thd)3], для формирования кислородсодержащих структ...

Raman microspectroscopy is a vibrational spectroscopy technique used for investigating molecular fingerprints of a wide range of liquid or solid samples. The technique can be efficiently utilized to understand the virus-mediated cellular changes and could provide valuable insights into specific biomolecular alterations. The Epstein Barr virus (EBV)...

A hybrid (Reduced Graphene Oxide) RGO+nano-WO3 flexible electrode on carbon cloth substrate has been designed for application as flexible supercapacitor electrode. The electrode has been designed by electrochemically reducing the graphene oxide onto a hydrothermally deposited nano-WO3 on flexible carbon cloth electrode for this purpose. The electro...

With the growing demand for monolayer MoS2 in diverse optoelectronic applications, it is more important than ever to understand carrier behavior under varied excitation conditions and at different excitonic levels. In this article, we show that band structure, excitation wavelength, and excitation density all have a significant impact on the carrie...

Used cigarette filters, a waste material and a major source of land pollution, were used as raw material to study the nature of condensed tobacco smoke (tar) using microscopy, optical, IR, photoluminescence, and Raman spectroscopy, as well as X-ray diffraction and electron and fluorescence microscopy. The tar present in the cigarette filter bud was...

Due to the growing interest in monolayer Molybdenum Disulfide (MoS2) in several optoelectronic applications like lasers, detectors, sensors, it is important to understand the ultrafast behavior of the excited carriers in this material. In this article, a comprehensive study of the charge carrier dynamics of a monolayer MoS2 flake has been studied u...

A dual purpose solid state electrochromic diode has been fabricated using polythiophene (P3HT) and ethyl Viologen (EV), predoped with multiwalled carbon nanotubes (MWCNTs) and MoS2. The device has been designed by considering two important aspects, first, the complementary redox activity of P3HT and EV and second, the electron holding properties of...

The Fermi energy is known to be dependent on doping and temperature, but finding its value and corresponding thermal Fermi shift experimentally is not only difficult but is virtually impossible if one attempts their simultaneous determination. We report that temperature dependent Raman spectromicroscopy solves the purpose easily and proves to be a...

It is always interesting to understand how the interplay between two perturbations, affects any physical process and gets manifested in a semiconductor. Temperature- and wavelength-dependent Raman Spectromicroscopy was performed on heavily-doped Si to reveal an unusual anti-anharmonic effect. Additionally, the energy dispersive behaviour of Fano co...

Temperature-dependent Raman spectromicroscopy of rutile TiO2 nanorods has been studied here to understand the effect of thermal perturbations on different Raman-active phonon modes. The TiO2 nanorods, characterized using electron microscopy, X-ray diffraction and Raman spectroscopy, were prepared using a hydrothermal method. Raman spectra, recorded...

The effect of the oxidizer present in the etching solution on the surface morphology and microstructure obtained after porosifying a p-type silicon wafer using metal-assisted chemical etching was studied. The morphologies of Si wafers porosified using two different solutions, HF/H2O2 and HF/KMnO4, were compared to establish how either of the oxidiz...

Raman spectroscopy is a proven versatile tool for characterization of materials spanning almost all areas of science because of its ability to non‐invasively extract information about materials. This technique is able to detect any perturbation in a system that can affect the phonons. A detailed discussion on various factors that affect the Raman l...

A solid state electrochromic device has been fabricated using molybdenum disulfide (MoS2) doped Ethyl viologen (EV) and polythiophene (P3HT) layers. The MoS2 nano flower has been synthesized by one-step hydrothermal method and characterized by electron spectroscopy, X-ray diffraction and Raman spectroscopy. The prepared solid state electrochromic d...