Arindam Das

• Ph.D.
• Researcher at Indira Gandhi Centre for Atomic Research

Sustainable pollutants remedial is focussed by using surfactant-free ZnS nanoparticles (NPs) which are decorated with elemental-type sulfur defects (E s). Such functional ZnS NPs enable complete and rapid degradations of dye, drug (paracetamol, tetracycline), and explosive (trinitro-phenol) with UV to visible light irradiations. The evi-dences of E...

Adsorption and photocatalysis processes are considered of high significance for the remediation of toxic dye in aquatic medium. Herein, we report a remarkable performance of uncapped SnO2 quantum dots (QDs) synthesized by varying drying process. Structure property correlations of QDs were evaluated by XRD, HRTEM, Raman, PL, FTIR, TGA, BET and Zeta...

The humidity sensor working at low pressure has importance in fruit processing industries, space applications, and vacuum coatings. So, it is imperative to develop a sensor to measure very low levels of humidity in a vacuum domain. In the present work, a resistive humidity sensor made of SnO2 Quantum Dots(QDs) is demonstrated. The huge surface area...

The predominant type of defect that are created by ion/neutron irradiation, in oxide nuclear fuel materials like thoria, is oxygen vacancy. In the present study, the effect of O-vacancies on the f-occupancy of thorium is studied using experiments and density functional theory (DFT) calculations. Thoria samples are irradiated with low energy (100 ke...

The non-stick & foul release property of silicones was first reported in the early 1970s, with surface free energy of 22 – 24 dynes/cm offering a minimally adhesive surface to biological organisms. The superior antifouling performance of tri-butyl tin- self-polishing coatings TBT-SPC systems outshone all other antifouling formulations from 1970 to...

The transfer of monolayer molybdenum disulfide (1L‐MoS2) onto any target substrates is inevitable for the next generation of optoelectronic devices such as flexible electronics. However, the existing post‐transfer treatments are ineffective for the complete removal of poly(methyl methacrylate) (PMMA) polymer, which is usually used as carrier polyme...

SnO2, an n-type semiconductor used commercially as resistive sensors at high temperature suffers from drifting voltage, contact resistances and poor selectivity. On the other hand, excellent optical property arising from defects in rutile SnO2 offers opportunities that remain to be explored for optical gas sensor applications. During optical detect...

Metal oxide nanoparticles (MONs) emerged as antimicrobials due to the occurrence of multidrug-resistant (MDR) bacterial strains. Antimicrobial activity has been shown to be influenced by the route of synthesis and precursors. Hence, a plethora of literature exists on prominent MONs like Ag2O, CuO, ZnO, TiO2, MgO, Al2O3, and Au, as activity was infl...

Silver nanowires (Ag NWs) are synthesized using hydrothermal method by maintaining a constant polyvinyl pyrrolidone (PVP): silver nitrate (AgNO3) molar ratio. The effect of concentration of AgNO3 under constant PVP: AgNO3 ratio on the formation of Ag NWs is examined. The morphological, structural, and optical properties of the obtained Ag NWs are s...

Au nanorods (AuNRs) with a variety of aspect ratios (ARs) are used in surface-enhanced Raman spectroscopy (SERS), thermal therapy, and similar applications. In this study, we report a seed-mediated synthesis of AuNRs to cover different ARs in a single step with diluted HCl. This process ensures the realization of longitudinal surface plasmon resona...

https://authors.elsevier.com/c/1dKSA,3pss0X3V Increased adhesion and biofilm formation by marine microalgae as well as inhibition of settlement of invertebrate larval forms on polydimethylsiloxane (PDMS) foul release coatings is a challenge to overcome. Copper oxide nanoparticles (CuO-NP) were synthesized by a wet chemical precipitation route and...

Polydimethyl siloxane (PDMS), CuO nanocomposites (NCs) were prepared using plain CuO and cetyltrimethyl ammonium bromide (CTAB) capped (0.05 & 1.0M) CuO nanoparticles as nanofillers. Incorporation of plain CuO and CuO-1M capped NP as nanofillers into PDMS altered their surface roughness and imparted biocidal activity by release of metal ions. CTAB...

Energy-efficient and environmentally benign photocatalyst with enormous reaction sites activated by similar wide spectrum of sunlight to treat an aqueous dye pollutant is of contemporary research interest. At the onset, an energy-friendly microwave radiation process is used to ascertain the single-step growth of 4 nm cubic ZnS quantum dots (QDs) wi...

Graphene oxide (GO) with beneficial functional groups regulates the surface chemistry for catalytic applications. However, the low electrical conductivity of GO invokes further treatments that compromise the above-valued properties. We report an interfacial engineering of GO decorated with SnO2 quantum dots (QDs) for the visible-light-driven cataly...

Defect chemistry in SnO 2 is well established for resistive sensors but remains to be elusive for photoluminescence (PL) sensors. It demands a comprehensive understanding of the role of cationic and oxygen defects as well as the creation of abundant such defects to provide a selective PL signal. To accomplish it, SnO 2 quantum dots (QDs ∼ 2.4 nm) a...

Chemically stable and biocompatible gold nanorods (Au NRs) are an excellent building block for plasmonic-based applications, including surface-enhanced Raman spectroscopy(SERS). However, the quest for controlling the aspect ratio (AR) for desirable application needs an in-depth understanding of the synthesis procedure. In this article, the seed-med...

Defects and deformation potential in quantum dots (QDs) were found to control the Raman modes however the disorder activated phonon (DAP) mode could not be seen in the cubic phase ZnS. With a maiden observation of a DAP mode the crucial role of surface defects, in particular, elemental ‘S’ is reported. The DAP mode was seen with significant intensi...

Synthesis of quantum dots (QDs) uses surfactants to enable its applications viable with minimum surface defects. The environmental benign method without a surfactant is a way forward for sustainable applications. Sunlight mediated synthesis of uniform ZnS QDs without a surfactant is achieved with pristine surface defects that facilitate visible lig...

For low dimension systems, symmetry breaking and surface reconstruction are critical for observation of special vibrational properties of technical significance like surface optical (SO), anharmonic and disorder activated phonon (DAP) modes. Firstly, earlier unobserved modes like SO and DAP are disclosed for the cubic ZnS nanoparticles (NPs) of 3 t...

For low dimension systems, symmetry breaking and surface reconstruction are critical for observation of special vibrational properties of technical significance like surface optical (SO), anharmonic and disorder activated phonon (DAP) modes. Firstly, earlier unobserved modes like SO and DAP are disclosed for the cubic ZnS nanoparticles (NPs) of 3 t...

Synthesis of quantum dots (QDs) uses surfactants to enable its applications viable with minimum surface defects. The environmental benign method without a surfactant is a way forward for sustainable applications. Sunlight mediated synthesis of uniform ZnS QDs without a surfactant is achieved with pristine surface defects that facilitate visible lig...

Wide applications of graphene oxide (GO) owe to unique abilities of its surface chemistry linked to the ubiquitous influence of oxygenated functional groups, especially for the electrochemical performance with metal oxides nanoparticles (NPs). In addition to the imbibed chemical property of NP, its size and shape are crucial for applications. In th...

The effects of two prominent copper oxide nanoparticles (CuO-NP and Cu2O-NP), with the oxidation state of Cu⁺⁺ (cupric) and Cu⁺ (cuprous), on Candida albicans were evaluated. CuO-NP and Cu2O-NP were synthesized and characterized by XRD, FESEM, HR-TEM and Zeta potential. At sub-MIC (50 µg ml⁻¹), both cupric and cuprous oxide NPs prevented yeast-to-h...

Biofilm formation on antifouling coatings is a serious concern in seawater cooling systems and the maritime industry. A prolific biofilm forming strain (Staphylococcus lentus), possessing high tolerance (>1,000 µg ml⁻¹) to dissolved copper ions (Cu⁺⁺) was isolated from titanium coupons exposed in the coastal waters of Kalpakkam, east coast of India...

Radioactive waste water gets generated as low level liquid effluent in nuclear power reactors, nuclear reprocessing and waste management plants. Organic wastes like oil, solvent extracting agents (like TBP), liquid scintillation chemicals, thinner, dodecane, kerosene, lipids, toluene, xylene, cyclohexane, ethylenediamine tetra acetic acid, oxalic a...

Observation of disorderliness phonon peak in cubic ZnS quantum dots (QDs) prepared without any capping agent is reported for the first time. A disorder activated phonon (DAP) mode was seen at 153 cm-1 including the Raman allowed mode, LO at 347 cm-1 for the cubic phase. Size of ZnS was varied from 3 nm to 5 nm to shed light on the disorderliness pe...

SnO2 QDs based optical sensing is realized by exploiting its photoluminescence properties. Simple sol-gel wet chemical process is used for preparing metal oxide nanoparticle. Crystalline particles of average size of 2.3 nm, equivalent to Bohr exciton radius of SnO2, are determined from transmission electron microscopy and X-ray diffraction studies....

Understanding the role of defects is important due to its influence on electrical and optical properties of SnO2. This study reports the role of oxygen defects in SnO2 quantum dots decorated in carbon paper for an improved electron transfer process in electrochemical applications. A simple and cost-effective chemical route for preparation of a SnO2...

Trace level methane (CH4) detection is demonstrated at low temperature. Functional metal oxide of SnO2 tailored by CuO is prepared via a co‐precipitation chemical route followed by annealing in air. Raman spectroscopy confirms presence of Ag mode of CuO at 290 cm⁻¹ along with A1g mode of SnO2 at 630 cm⁻¹. Results from the X‐ray diffraction and tran...

Shuttling of lithium polysulphides and the formation of lithium dendrites are the key challenges that impede the commercialization of high-capacity lithium–sulphur batteries. Here, we report on a binder-free novel aluminium nanolayer–coated polypropylene separator prepared by radio frequency magnetron sputtering technique for shuttle-free lithium m...

Thermal annealing of Ag-Cu bi-layer thin films on silica-glass substrates either in air or in oxygen environment has led to the formation of novel composite materials (Ag nanoparticles in compound metal oxide semiconductors). Optical absorption and electron microscopy results have confirmed the presence of Ag nanoparticles in oxide semiconductor ma...

Vanadium oxides are anticipated as a high-performance energy storage electrode due to their coupled double layer and pseudo-capacitative charge storage mechanism. In the present work, we investigated the influence of different structural phases of as-grown VO2 nanoporous structure and corresponding oxidation states on the supercapacitor performance...

Poly (methyl methacrylate) (PMMA) is an extensively used implant material in biomedical devices. Biofilm formation creates issues in PMMA-based biomedical implants, while emergence of drug resistant pathogens poses an additional complication. Hence development of surfaces that resist bacterial colonisation is extremely desirable. In this context, n...

One-dimensional (1D) SnO2 sub-wavelength waveguides are a critical contribution to advanced optoelectronics. Further understanding of the surface defects and role of morphology in 1D SnO2 nanowires can help to better utilize these nanostructures more efficiently. For this purpose, three different nanowires (NWs), namely belts, cylindrical- and squa...

Quantum sized ZnS with large surfaces displays novel optical, electronic, chemical, and structural properties that may find many important technological applications. Here we have prepared QDs ZnS using microwave process which is rapid due to volumetric heating by irradiation of precursors and offers homogeneous particles of 4 nm. X-ray diffraction...

We determine down to 1 nM of oxalic acid (OA) using quantum dots (QDs) ZnS without capping ligand. Salts of OA can become health hazard warranting low concentration detection of OA. The control on size with enriched 'S' defects only allowed the application of UV-Vis spectroscopy for manipulation of defects-OA interaction to decipher quantitative OA...

Despite of useful applications of Ag, it is hazardous to health and environment and hence early detection is required. Crystal defects influencing optical property is less likely utilized for Ag detection using prevalent UV-Vis technique. Quantum dots (QDs) ZnS prepared by soft chemical route are exploited for the detection of Ag+ in aqueous soluti...

To investigate formation and dynamics of Au nanoparticles in a silica-glass, Au²⁺ ions are implanted in silica matrix at elevated temperatures up to 600 °C. Optical absorption, Raman spectroscopy and electron microscopy results confirm athermal growth of the Au nanoparticles. Growth dynamics has strong dependence on ion fluences and target temperat...

Despite of useful applications of Ag, it is hazardous to health and environment and hence early detection is required. Crystal defects influencing optical property is less likely utilized for Ag detection using prevalent UV-Vis technique. Quantum dots (QDs) ZnS prepared by soft chemical route are exploited for the detection of Ag ions in aqueous so...

Gas sensors at low operating temperature with high sensitivity are the demand for the group III nitrides owing to their high chemical and thermal stability. The CH4 sensing is realized for the Al0.07Ga0.93N nanowires (NWs) with an improved response over the GaN NWs at a low operating temperature of 50 {\deg}C, for the first time. Al0.07Ga0.93N NWs...

Gas sensors at low operating temperature with high sensitivity are demand for the group III nitrides owing to their high chemical and thermal stability. The CH4 sensing is realized for the Al0.07Ga0.93N nanowires with an improved response over the GaN NWs at a low operating temperature of 50 °C, for the first time. Al0.07Ga0.93N nanowires (NWs) wer...

Influence of non stoichiometric layer to the possible contribution towards the unusually high dielectric constant of n-type SnO2 is discussed. Oxygen deficient and oxygen rich environments during the growth of SnO2 nanoparticles synthesized from the as prepared SnO2 quantum dots (QDs) of ∼2.4 nm have enabled creation of various defects states; howe...

Silver (Ag) has large applications e.g. excellent electrical and thermal conductors, metal reflectors, anti-bacterial uses and in jewel industries. However, it is found to be hazardous and potent threat to health and environment [1]. The Environmental protection agency has set maximum contaminant level for Ag at 0.1 mg/L (0.93 μM) and therefore it...

Thermal mixing of thin films of Ag and Cu metals on a silicaglass substrate in an ambient environment has lead to the formation of a novel material(Agmetalnanoparticles in the AgCuO2 semiconductor). Dipolar and quadrupolar optical resonances observed in samples annealed at 300 °C have confirmed the presence of Agmetalnanoparticles in the semiconduc...

Vanadium pentoxide (V2O5), the most stable member of vanadium oxide family, exhibits interesting semiconductor to metal transition in the temperature range of 530-560 K. The metallic behavior originates because of the reduction of V2O5 through oxygen vacancies. In the present report, V2O5 nanorods in the orthorhombic phase with crystal orientation...

Vertical graphene nanosheets (VGN) is a potential material for high-performance supercapacitors due to its high surface area, open interconnected network and excellent electrical conductivity. Selection of proper aqueous electrolyte is crucial for its utilization as supercapacitor electrode. The present study reports supercapacitive performance of...

In this work high dielectric of SnO2 at lower frequency is correlated with presence of in plane oxygen vacancy .

Vanadium pentoxide (V2O5), the most stable member of vanadium oxide family, exhibits interesting semiconductor to metal transition in the temperature range of 530-560K. The metallic behavior originates because of the reduction of V2O5 through oxygen vacancies. In the present report, V2O5 nanorods in the orthorhombic phase with crystal orientation o...

The vertical graphene nanosheets (VGNs) have attracted considerable attention for energy storage application due to their inherent properties such as morphology, large surface area, high electrical conductivity and three dimensional (3D) open network structures. Here, we report on the growth of VGNs using electron cyclotron resonance - chemical vap...

Hydrogen free Diamond like Carbon (DLC) thin films enriched with C-C sp3 bonding were grown on Si (111) substrates at laser pulse energies varying from 100 to 400 mJ (DLC-100, DLC-200, DLC-300, DLC-400), by Pulsed Laser Ablation (PLA) utilizing an Nd:YAG laser operating at fundamental wavelength. Structural, optical and morphological evolutions as...

The physicochemical processes at the surfaces of semiconductor nanostructures involved in electrochemical and sensing devices are strongly influenced by the presence of intrinsic or extrinsic defects. To reveal the surface controlled sensing mechanism, intentional lattice oxygen defects are created on the surfaces of GaN nanowires for the elucidati...

Metal oxide nanostructures are widely used in energy applications like super capacitors and Li-on battery. Smaller size nanocrystals show better stability, low ion diffusion time, higher-ion flux and low pulverization than bigger size nanocrystals during electrochemical operation. Studying the distinct properties of smaller size nanocrystals such a...

Vertical graphene nanosheets (VGN) grown as controlled porous network are studied and demonstrated as a promising electrode material for supercapacitors. The VGN synthesized by microwave plasma enhanced chemical vapor deposition using CH4/Ar gas mixture as precursor are considered for electrochemical performance in Na2SO4, KOH, and H2SO4 to delinea...

Polydimethyl siloxane (PDMS) is an excellent implant material for biomedical applications, but often fails as it is prone to microbial colonization which forms biofilms. In the present study CuO, CTAB capped CuO, and ZnO nanoparticles were tested as nanofillers to enhance the antibiofilm property of PDMS against Staphylococcus aureus and Escherichi...

Nanofluid lubrication is a novel approach for enhancing energy efficiency of the sliding interfaces which is useful for reducing friction and wear of the machine elements. SnO2 is a wide band gap (3.62 eV) non toxic and chemically stable material. The SnO2 nanoparticles (NPs) of 25 nm size and concentration 0.03 mg mL–1 dispersed in polyolester (PO...

The physicochemical processes at the surfaces of semiconductor nanostructures involved in electrochemical and sensing devices are strongly influenced by the presence of intrinsic or extrinsic defects. For revelation of the surface controlled sensing mechanism, intentional lattice oxygen defects are created on the surfaces of GaN nanowires for the e...

Raman forbidden modes and surface defect-related Raman features in SnO2 nanostructures carry information about disorder and surface defects which strongly influence important technological applications like catalysis and sensing. Because of the weak intensities of these peaks, it is difficult to identify these features by using conventional Raman s...

We report, for the first time, the luminescence property of the hydroxyl group surface functionalized quantum dots (QDs) and nanoparticles (NPs) of SnO2 using low energy excitations of 2.54 eV (488 nm) and 2.42 eV (514.5 nm). This luminescence is in addition to generally observed luminescence from ?O? defects. The as-prepared SnO2 quantum dots (QDs...

Role of “O” defects in sensing pollutant with nanostructured SnO2 is not well understood, especially at low temperatures. SnO2 nanoparticles were grown by soft chemistry route followed by subsequent annealing treatment under specific conditions. Nanowires were grown by chemical vapor deposition technique. A systematic photoluminescence (PL) investi...

High value of magnetic moment 0.08 emu/g at room temperature for SnO2 NPs was observed. Surface functionalization with octadecyltrichlorosilane (OTS) enhanced the saturation magnetic moment of NPs to an anomalously high value of 0.187 emu/g by altering the electronic configuration on NPs surface. Surface functionalization also suppressed photolumin...

High magnetic moment was observed in SnO2 quantum dots (QDs) which were prepared by a soft chemical method. SnO2 QDs were characterized for morphological, structural and optical properties using high resolution tunneling electron microscopy and photoluminescence (PL) spectroscopy, respectively. Magnetism occurred in QDs SnO2 due to dominant oxygen...

Role of “O” defects in sensing pollutant with nanostructured SnO2 is not well understood, especially at low temperatures. SnO2 nanoparticles were grown by soft chemistry route followed by subsequent annealing treatment under specific conditions. Nanowires were grown by chemical vapor deposition technique. A systematic photoluminescence (PL) investi...

SnO2 quantum dots (QDs) were prepared in a soft chemical route and subsequently were functionalized with octadecyltrichlorosilane (OTS) to make solid thin films by Langmuir-Blodgett technique. Raman spectroscopy study provided evidence of surface bonding of OTS with QDs. UV-Visible spectroscopy study revealed a fixed transfer ratio for the growth o...

Measuring the size of the quantum dots (QDs) with accuracy is crucial considering its effect on the physical and chemical properties. Size determination of SnO2 QDs prepared by a soft chemical method using various techniques and their correlation is reported here. Direct method like high resolution transmission electron microscopy (HRTEM), and indi...

The role of quantum dots (QDs) of SnO2 in detecting low concentrations of methane (CH4) at a relatively low temperature of 150 °C with high response (S 3.5%) and response time below 1 min is reported. A simple room temperature single step chemical process was adopted for the growth of SnO2 nanoparticles of a size around 2.4 nm. These nanoparticles...

Understanding the mechanism of nanoparticle (NP) induced toxicity in microbes is of potential importance to a variety of disciplines including disease diagnostics, biomedical implants, and environmental analysis. In this context, toxicity to bacterial cells and inhibition of biofilm formation by GaN NPs and their functional derivatives have been inv...

Nanostructured yttria stabilized ZrO2 (YSZ) films are prepared by electron beam deposition and subsequently characterized by using X-ray diffraction, field emission scanning electron microscopy, and UV-Vis spectroscopy. A capacitive device with Al/YSZ/Al structure acts as a sensor for analytes like ammonia solution, acetone, and alcohols. Low power...

Modulation of surface wettability is demonstrated using SnO2 nanoparticles (NPs) upon surface functionalization. Quantum sized SnO2 NPs synthesized by soft chemical route are annealed under ambient conditions at different temperatures to increase grain size as revealed by field emission scanning electron microscopy, transmission electron microscopy...

Nano particles (NPs) of Ag are utilized as surface enhanced Raman scattering substrates to probe molecular arrangement and interactions. Pd NPs are prepared by reduction process in the presence of biologically active cetyl trimethylammonium bromide (CTAB). Ultra thin Langmuir Blodgett films of Pd-CTAB are deposited on the SiO2 and the Ag/SiO2 SERS...

Antibiofilm properties of bulk and nano-sized copper oxide (CuO) were investigated using four species of bacteria viz: Staphylococcus aureus, E. coli, Pseudomonas aeuriginosa (PAO1) and Pseudomonas putida. The effect of both commercial and synthesized nanoparticles on biofilm formation was investigated using different concentrations 0.02, 0.12, 0.2...

Toxicity of nano scaled Ga2O3 and functionalized (carboxyl -COOH; amine -NH) nanoparticles was examined against a gram positive (Staphylococcus aureus) and gram negative (Escherichia coli) bacteria. NP concentrations in the range of 0.25 to 25 µg/mL were tested. Strain specificity in antimicrobial activity was observed. Ga2O3 treatments resulted in...

Sensitive, reproducible multi-parameter sensor properties are demonstrated by using an amorphous organic semiconductor as an active layer of the field effect transistor. Anodized aluminium as a nano gate insulator allowed low power OFET fabrication. Utility of such device over the chemiresistor is described. A highly sensitive NO2 sensor that shows...

The High k thin films of ZrO2 were deposited by electron beam evaporation for creating high capacitance devices. Capacitance as high as 0.2 μF/cm2 is obtained for the 80 nm thick ZrO2 films that forms thickness equivalent of SiO2∼16 nm (teq). Grazing incidence XRD confirmed crystalline tetragonal phase. Morphology of ZrO2 films investigated using a...

CuO nanoparticles have been synthesized by the hydrothermal route using two different organometallic and inorganic precursors of copper acetylacetonate [Cu(C5H7)2:Cu(AA)2] and hydrated copper nitrate [Cu(NO3)2.3H2O], respectively. Detailed structural and vibrational studies have been carried out using x-ray diffraction, transmission electron micros...

Electronic noses (e-noses) are increasingly being used as vapour sensors in a range of application areas. E-noses made up of arrays of organic field-effect transistors (OFETs) are particularly valuable due the range and diversity of the information which they provide concerning analyte binding. This study demonstrates that arrays of OFETs, when com...

Results from studies of spin dependent transport in the hole transporting organic semiconductor regioregular poly 3-hexylthiophene (RR-P3HT) are reported. The organic spin valves were grown on glass, with the structure Fe ₅₀ Co ₅₀/ R R - P 3 H T / Ni ₈₁ Fe ₁₉ . RR-P3HT was cast from five different solvent...