IR@CGCRI - Central Glass and Ceramic Research Institute (CSIR)
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Low power paper electronics based wearable radiation detector using hybrid halide perovskite (MAPbBr(3)): A real time monitoring of gamma ray
No full textIn this report we demonstrate that a paper based flexible gamma ray detector can be made using hybrid halide perovskite methyl ammonium lead bromide (CH3NH3PbBr3 or MAPB). The wearable paper based detector is solution processed and works at room temperature. It detects gamma ray by a direct method by change of its resistance on exposure to gamma ray and uses IDE (interdigitated electrodes) for boosting current response. This detector grown on a substrate like a paper with large active area, shows a maximum calibrated sensitivity of 5.26 mu C Gy(-1) cm(-2) and a reasonable mobility-life time product ( mu tau) similar to 5 cm(2) V-1. The detector can be operated in a wide range of gamma photon energy between 100 KeV to 1100 KeV and can detect radiation down to 0.01 mu Ci activity, which is noise limited. The paper detector shows a good shelf life of more than 6 months and a fast response time of a few seconds. The detector has a high degree of sustenance under exposure to high dose of Gamma radiation and was tested for a cumulative dose of minimum 1.6 KGy. The detector has low power consumption with can operate down to 1 V direct current (DC) bias and with a detector current of similar to 1nA. The sensitivity increases with bias and shows saturation beyond 40 V bias. Such a low power flexible gamma detector is expected to have application potential in areas like health care and point of use quick radiation detection
Microfibers of fish waste-derived collagen and ion-doped bioactive glass in stimulating the healing sequences in full-thickness cutaneous burn injury
No full textBurns are extremely debilitating, requiring prompt and prolonged therapeutic protocol for ensuring healing and survivability. For efficient burn coverage and controlling the inflammation, and infection as well as triggering the overall wound healing cascade there is an incessant demand to generate a dressing material as an adjunct burn therapy. We fabricated five different types of microfibrous mats having bioactive properties using pristine fish collagen and in combination with bioactive glass/ion-doped bioactive glass. All the mats were cytocompatible with human dermal fibroblasts supporting cellular adherence, proliferation, and viability. The mats also ensured enhanced wound healing in full-thickness cutaneous burns in the rabbit model. The fish collagen/ion-doped microfibrous mats in particular showed a better response in terms of neovascularization, re-epithelialization, and ECM component deposition such as collagen and elastin. The wounds treated with Fcol/CuCoBG mat demonstrated a significantly (p < 0.01) greater regeneration of blood vessels compared to all the other groups. Such features indicate the intrinsic bioactive roles of fish collagen and ion-doped bioactive glass towards favorable regeneration and closure of burn wounds thereby establishing its potency in burn care
Nature-Driven Biocompatible Epidermal Electronic Skin for Real-Time Wireless Monitoring of Human Physiological Signals
No full textWearable bioelectronic patches are creating a transformative effect in the health care industry for human physiological signal monitoring. However, the use of such patches is restricted due to the unavailability of a proper power source. Ideal biodevices should be thin, soft, robust, energy-efficient, and biocompatible. Here, we report development of a flexible, lightweight, and biocompatible electronic skin-cum-portable power source for wearable bioelectronics by using a processed chicken feather fiber. The device is fabricated with a novel, breathable composite of biowaste chicken feather and organic poly(vinylidene fluoride) (PVDF) polymer, where the chicken feather fiber constitutes the ``microbones'' of the PVDF, enhancing its piezoelectric phase content, biocompatibility, and crystallinity. Thanks to its outstanding pressure sensitivity, the fabricated electronic skin is used for the monitoring of different human physiological signals such as body motion, finger and joint bending, throat activities, and pulse rate with excellent sensitivity. A wireless system is developed to remotely receive the different physiological signals as captured by the electronic skin. We also explore the capabilities of the device as a power source for other small electronics. The piezoelectric energy harvesting device can harvest a maximum output voltage of similar to 28 V and an area power density of 1.4 mu W center dot cm-2 from the human finger imparting. The improved energy harvesting property of the device is related to the induced higher fraction of the electroactive phase in the composite. The easy process ability, natural biocompatibility, superior piezoelectric performance, high pressure sensitivity, and alignment toward wireless transmission of the captured data make the device a promising candidate for wearable bioelectronic patches and power sources
Enhanced thermoelectric performance of mechanically hard nano-crystalline-sputtered SnSe thin film compared to the bulk of SnSe
No full textThermoelectric thin-film architecture has the advantage over bulk by reducing further the thermal conductivity and increasing the figure of merit. The present work demonstrates the structural requirement to enhance the figure of merit and hardness of a SnSe thin film over bulk. The SnSe thin films were deposited over the glass substrate at different substrate temperatures (Ts) using the magnetron-sputtering technique. The bulk and the deposited films of SnSe were characterized by XRD, SEM, EDS, Raman spectroscopy, HRTEM, Nano-indentation, and thermoelectric properties (Seebeck coefficient, electrical, and thermal conductivities) measurement techniques. The structural, compositional, thermoelectrical, and mechanical analyses of films were used to establish the structure-property relationship for SnSe. The microstructure of the SnSe films was significantly affected by Ts. The well-evolved single-phase polycrystalline structure of the SnSe films was observed at high Ts (>= 400 degrees C). The planar orientations overlapping induced dislocations were observed at high Ts. The maximum ZT (0.83), power factor (similar to 2.43 mu Wcm(-1) K-2), and hardness (7.1 GPa) values were obtained for the SnSe film deposited at Ts = 500 degrees C. The structural modifications of SnSe thin film at high temperatures implemented by nano-crystallization, preferred orientation (111), grain boundaries, and competitive growth-induced dislocations were responsible for enhancing the figure of merit and hardness compared to bulk SnSe
Phase coexistence and resistance relaxation kinetics in NdNiO3 films below the metal-insulator transition temperature
Full text linkCoexistence of electronically distinct phases below metal-insulator (MI) transition temperature (T-MI) in correlated oxides undergoing temperature-driven MI transition has been observed in a number of systems. One of the consequences of the coexisting phases is that the metastable high-temperature metallic phase transforms into the stable insulating phase with a finite relaxation time as the temperature is lowered below T-MI. We report an extensive investigation of the phase transformation (referred to as relaxation) using resistivity as a tool where the ramp-dependent hysteresis and isothermal annealing-induced resistance relaxation were studied in films of NdNiO3 grown on three different crystalline substrates (LaAlO3, SrTiO3, and BaTiO3/SrTiO3) down to 10 K, well below the metal-insulator transition temperature. The resistance relaxation experiments were complemented with Raman spectroscopy and high-resolution x-ray diffraction done down to 5 K and reciprocal space mapping (RSM). Isothermal annealing experiment done to temperatures 0 at this temperature. The resistance relaxation data were linked to x-ray diffraction and Raman spectroscopy data done to temperatures well below T-MI, in order to have a structural basis for the coexisting phases and their likely participation in the relaxation process. The experiments (both hysteresis and isothermal annealing) were analyzed by Monte Carlo simulation based on a minimal set of parameters, namely, a temperature T* and an energy scale of transformation E*, which themselves had a temperature dependence. The parameters used in the simulation and other experimentally observed quantities like the width and height of hysteresis were found to be correlated with certain structural parameters, in particular, the residual in-plane strain and the crystallite grain size that determine the size range in these films
Zn3Sb4O6F6 and KI-Doped Zn3Sb4O6F6: A Metal Oxyfluoride System for Photocatalytic Activity, Knoevenagel Condensation, and Bacterial Disinfection
No full textZn3Sb4O6F6 crystallites were synthesized by a pH-regulated hydrothermal synthetic approach, while doping on Zn3Sb4O6F6 by KI was performed by the ``incipient wetness impregnation technique.'' The effect of KI in Zn3Sb4O6F6 is found with the changes in morphology in the doped compound, i.e., needle -shaped particles with respect to the irregular cuboid and granular shaped in the pure compound. Closer inspection of the powder diffraction pattern of doped compounds also reveals the shifting of Braggs' peaks toward a lower angle and the difference in cell parameters compared to the pure compound. Both metal oxyfluoride comprising lone pair elements and their doped compounds have been successfully applied as photocatalysts for methylene blue dye degradation. Knoevenagel condensation reactions were performed using Zn3Sb4O6F6 as the catalyst and confirmed 99% yield even at 60 degrees C temperature under solvent-free conditions. Both pure and KI-doped compounds were tested against several standard bacterial strains, i.e., Enterobacter sp., Escherichia coli, Staphylococcus sp., Salmonella sp., Bacillus sp., Proteous sp., Pseudomonas sp., and Klebsiella sp. by the ``disk diffusion method'' and their antimicrobial activities were confirmed
Facile and Green Synthesis of Novel Fluorescent Carbon Quantum Dots and Their Silver Heterostructure: An In Vitro Anticancer Activity and Imaging on Colorectal Carcinoma
No full textCarbon dots (CQDs) have been widely investigated as prime candidates for developing a tumor theranostic platform due to their tunable fluorescence emission and excitation, high water solubility, good photostability, and biocompatibility. Among the CQDs, natural CQDs are an emerging class of nanomaterials in the carbon family. Herein, highly fluorescent carbon quantum dots (CQDs) were synthesized from orange juice using a one-step hydrothermal method and characterized by different techniques. After that, CQD/Ag heterostructures were synthesized by the reduction of silver salt, in particular silver nitrate (AgNO3) solution using sodium borohydride (NaBH4) in different ratios. The photostability and characterization of CQD/Ag heterostructures were investigated. At last, a comparative cellular toxicity measure-ment was done to select the superior CQD/Ag heterostructure in the human colorectal carcinoma (HCT 116) cell line along with the imaging property. The detailed cell death signaling was also observed in the HCT 116 cell line via the ROS-dependent mitochondrial-mediated pathway, where Akt (RAC-alpha serine/threonine-protein kinase) played a important role
Advanced Sustainable Trilayer Cellulosic ``Paper Separator'' Functionalized with Nano-BaTiO3 for Applications in Li-Ion Batteries and Supercapacitors
No full textIn the quest of developing a sustainable, low-cost andimprovedseparator membrane for application in energy storage devices likelithium-ion batteries (LIBs) and supercapacitors (SCs), here we fabricateda trilayer cellulose-based paper separator engineered with nano-BaTiO3 powder. A scalable fabrication process of the paper separatorwas designed step-by-step by sizing with poly-(vinylidene fluoride)(PVDF), thereafter impregnating nano-BaTiO3 in the interlayerusing water-soluble styrene butadiene rubber (SBR) as the binder andfinally laminating the ceramic layer with a low-concentration SBRsolution. The fabricated separators showed excellent electrolyte wettability(216-270%), quicker electrolyte saturation, increased mechanicalstrength (43.96-50.15 MPa), and zero-dimensional shrinkageup to 200 degrees C. The electrochemical cell comprising graphite|paperseparator|LiFePO4 showed comparable electrochemical performancesin terms of capacity retention at different current densities (0.05-0.8mA/cm(2)) and long-term cycleability (300 cycles) with coulombicefficiency >96%. The in-cell chemical stability as tested for 8weeksrevealed a nominal change in bulk resistivity with no significantmorphological changes. The vertical burning test as performed on apaper separator showed excellent flame-retardant property, a requiredsafety feature for separator materials. To examine the multidevicecompatibility, the paper separator was tested in supercapacitors,delivering a comparable performance to that of a commercial separator.The developed paper separator was also found to be compatible withmost of the commercial cathode materials such as LiFePO4, LiMn2O4, and NCM111
Pump power induced instability and hysteresis in an all-normal dispersion linear mode-locked fiber laser
No full textIn this manuscript, experimental studies on the instability and hysteresis in an all-normal dispersion (ANDi) fiber laser have been presented. The laser was mode-locked by using a semiconductor saturable absorber mirror and a chirped fiber Bragg grating in linear cavity configuration and under the stable conditions it delivered stationary dissipative soliton pulses with characteristic rectangular-shaped steep-edged spectrum. With increasing the pump power, the laser transits to a non-stationary state with a near trapezoidal-shaped spectrum with significant temporal instabilities. The hysteresis associated with the state transition and variations in spectral characteristics has been studied including dispersive Fourier transform based analysis. Pump power induced state transition in an ANDi linear cavity with a physical saturable absorber without the influence of any physical polarization controller or apparent limitation due to spectral filtering is the key observation presented in this paper
Synthesis and Characterizations of Bioactive Glass Nanoparticle-Incorporated Triblock Copolymeric Injectable Hydrogel for Bone Tissue Engineering
No full textRecently, injectable hydrogels have attracted much interest in tissue engineering (TE) applications because of their controlled flowability, adaptability, and easy handling properties. This work emphasizes the synthesis and characterizations of bioactive glass (BAG) nanoparticle-reinforced poly(ethylene glycol) (PEG)- and poly(N-vinylcarbazole) (pNVC)-based minimally invasive composite injectable hydrogel suitable for bone regeneration. First, the copolymer was synthesized from a combination of PEG and pNVC through reversible addition–fragmentation chain-transfer (RAFT) polymerization and nanocomposite hydrogel constructs were subsequently prepared by conjugating BAG particles at varying loading concentrations. Gel permeation chromatography (GPC) analysis confirmed the controlled nature of the polymer. Various physicochemical characterization results confirmed the successful synthesis of copolymer and nanocomposite hydrogels that showed good gelling and injectability properties. Our optimal nanocomposite hydrogel formulation showed excellent swelling properties in comparison to the copolymeric hydrogel due to the presence of hydrophilic BAG particles. The bone cell proliferation rate was found to be evidently higher in the nanocomposite hydrogel than in the copolymeric hydrogel. Moreover, the enhanced level of ALP activity and apatite mineralization for the nanocomposite in comparison to that for the copolymeric hydrogel indicates accelerated in vitro osteogenesis. Overall, our study findings indicate BAG particle-conjugated nanocomposite hydrogels can be used as promising grafting materials in orthopedic reconstructive surgeries complementary to conventional bone graft substitutes in cancellous bone defects due to their 3D porous framework, minimal invasiveness, and ability to form any desired shape to match irregular bone defects