Experimental and computational DFT, drift-diffusion studies of cobalt-based hybrid perovskite crystals as absorbers in perovskite solar cells.

The optimised designs of dimethyl ammonium cobalt formate-based perovskite crystals [(CH3)2NH2]Co(HCOO)3 were experimentally synthesized and computationally utilized as absorbers for perovskite solar cells (PSCs). Crystals were grown using solvothermal synthesis. Additive materials (Fe, Ni) are responsible for the growth and suppression of crystals in the micrometre range. Temperature and pressure were altered to obtain optimum growth conditions. Grown crystals were characterized by spectroscopy (XRD, FT-IR, UV-Vis) and optical microscopy. Combined density functional theory (DFT) and drift-diffusion modelling frameworks were simulated. These simulators were used to examine various perovskite absorbers for solar-cell configurations. Field calculations were used to examine the structural stability, band structure, and electronic contribution of the constituent elements in [(CH3)2NH2]Co1-nMn(HCOO)3 (M = Fe, Ni and n = 0, 0.1) as absorber material. Conventional TiO2 and spiro-OMeTAD were used as the electron-transport layer and hole-transport layer, respectively, and Pt was used as a back contact. Comprehensive analysis of the effects of several parameters (layer thickness, series and shunt resistances, temperature, generation-recombination rates, current-voltage density, quantum efficiency) was carried out using simulation. Our proposed strategy may pave the way for further design of new absorber materials for PSCs.

Exploring antimicrobial and biocompatible applications of eco-friendly fluorescent carbon dots derived from fast-food packaging waste transformation.

In the face of escalating environmental concerns, particularly the pervasive issue of non-biodegradable fast-food packaging waste, this study introduces a ground-breaking solution that not only addresses waste management but also advances biomedical technology. Utilizing the underexploited resource of Fucoidan, a sulfated polysaccharide from brown algae, we have innovatively transformed fast-food packaging waste into eco-friendly fluorescent carbon dots (FPCDs). These FPCDs were meticulously characterized through advanced techniques like FT-IR, TEM, and XRD, shedding light on their unique structure, morphology, and composition. A significant discovery of this study is the potent antimicrobial properties of these FPCDs, which demonstrate remarkable effectiveness against specific bacterial and fungal strains. This opens new avenues in the realm of biomedical applications, including imaging, drug delivery, and biosensing. Furthermore, extensive toxicity assessments, including the Brine shrimp lethality assay and Adult Artemia toxicity tests, underscore the safety of these nanoparticles, bolstering their applicability in sensitive medical scenarios. Our research presents a compelling dual approach, ingeniously tackling environmental sustainability issues by repurposing waste while simultaneously creating valuable materials for biomedical use. This dual benefit underscores the transformative potential of our approach, setting a precedent in both waste management and medical innovation.

Natural Solid-State Hydrogel Electrolytes Based on 3D Pure Cotton/Graphene for Supercapacitor Application.

A conductive cotton hydrogel with graphene and ions can come into contact with electrodes in solid electrolytes at the molecular level, leading to a more efficient electrochemical process in supercapacitors. The inherently soft nature of cotton mixed with hydrogel provides superior flexibility of the electrolyte, which benefits the devices in gaining high flexibility. Herein, we report on the current progress in solid-state hydrogel electrolytes based on 3D pure cotton/graphene and present an overview of the future direction of research. The ionic conductivity of a complex hydrogel significantly increased by up to 13.9 × 10-3 S/cm at 25 °C, due to the presence of graphene, which increases ionic conductivity by providing a smooth pathway for the transport of charge carriers and the polymer. Furthermore, the highest specific capacitance of 327 F/g at 3 mV/s was achieved with cyclic voltammetry measurement and a galvanostatic charge-discharge measurement showed a peak value of 385.4 F/g at 100 mA/g current density. Furthermore, an electrochemical analysis demonstrated that a composite cotton/graphene-based hydrogel electrolyte is electrically stable and could be used for the design of next-generation supercapacitors.

Highly Conductive and Reusable Cellulose Hydrogels for Supercapacitor Applications.

We report Na-Alginate-based hydrogels with high ionic conductivity and water content fabrication using poly (3,4-ethylene dioxythiophene) (PEDOT): poly (4-styrene sulfonic acid) (PSS) and a hydrogel matrix based on dimethyl sulfoxide (DMSO). DMSO was incorporated within the PEDOT:PSS hydrogel. A hydrogel with higher conductivity was created through the in-situ synthesis of intra-Na-Alginate, which was then improved upon by H2SO4 treatment. Field emission scanning electron microscopy (FESEM) was used to examine the surface morphology of the pure and synthetic hydrogel. Structural analysis was performed using Fourier-transform infrared spectroscopy (FTIR). Thermogravimetric analysis (TGA), which examines thermal properties, was also used. A specific capacitance of 312 F/g at 80 mV/s (energy density of 40.58 W/kg at a power density of 402.20 W/kg) at 100 DC mA/g was achieved by the symmetric Na-Alginate/PEDOT:PSS based flexible supercapacitor. The electrolyte achieved a higher ionic conductivity of 9.82 × 10-2 and 7.6 × 10-2 Scm-1 of Na-Alginate and a composite of Na-Alginate/PEDOT:PSS at 25 °C. Furthermore, the supercapacitor Na-Alginate/PEDOT:PSS//AC had excellent electrochemical stability by showing a capacity retention of 92.5% after 3000 continuous charge-discharge cycles at 10 mA current density. The Na- Alginate/PEDOT:PSS hydrogel displayed excellent flexibility and self-healing after re-contacting the two cut hydrogel samples of electrolyte for 90 min because of the dynamic cross-linking network efficiently dissipated energy. The illumination of a light-emitting diode (LED) verified the hydrogel's capacity for self-healing.

Biodegradable composites from poly(butylene adipate-co-terephthalate) with carbon nanoparticles: Preparation, characterization and performances.

The development of composites for food packaging that have good mechanical and antimicrobial characteristics is still a major challenge. In applications like food packaging, the usage of poly (butylene adipate-co-terephthalate) (PBAT), which has an adversative effect on the environment and reduces petroleum resources, has grown widespread. The present work reveals PBAT composites reinforced with CNPs at a few percentages up to 5.0 wt %. The PBAT/CNPs composites were produced using the solvent casting method. The results of TGA studies, CNPs significantly enhanced the thermal stability of composites using PBAT. The mechanical strength of the PBAT composites was improved by increasing CNPs concentration. Tensile strength increased from 7.38 to 10.22 MPa, respectively. The oxygen transmission rate (OTR) decreased with increasing the CNPs concentrations. The barrier properties (H2O and O2) of PBAT were improved by the presence of CNPs. WVTR was calculated to be 108.6 ± 1.8 g/m2/day for PBAT. WVTR reduced when CNPs concentration in PBAT increased. The PCN-5.0 film sample had the lowest WVTR value, 34.1 ± 3.1 g/m2/day. For PCN-3.0, WVTR dropped by 45.39%, indicating and even with a 3.0 wt% loading of CNPs in PBAT, the rise is noticeable. Contact angle measurements indicate that PBAT/CNPs composites becomes hydrophobic after reinforcing. Gram-positive (S. aureus) and Gram-negative (E. coli) food-borne pathogenic microorganisms showed enhanced antimicrobial activity against the developed PBAT composites. The carrot pieces preserved their freshness for an extended period of 12 days while packaged in the PBAT/CNPs composite film, indicating that the film is an effective and excellent packaging for food materials.

Electro-sensing layer constructed of a WO3/CuO nanocomposite, for the electrochemical determination of 2-phenylphenol fungicide.

The abstract highlights the development of an electroanalytical sensor for the detection of 2-phenylphenol (2-PPL) as a contaminant. The novelty of the experiment lies in the utilization of a 1-D nanostructured WO3/CuO nanocomposite integrated with a carbon paste electrode (CPE). The hydrothermal method was used to synthesize the WO3 NPs, which were then characterized using Scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS) techniques. Tungsten oxides (WO3) have been the subject of extensive study because of their many desirable characteristics, including their ease of preparation, tunable stoichiometry, crystal structure, particle morphology, 2.6 eV bandgap, excellent photocatalytic oxidation capacity, non-toxic nature, and widespread availability. The narrow band gap in CuO makes it an ideal sensing material. Copper oxide has applications in many different industries because it is a semiconductor metal with a narrow band gap in the spectrum of 1.2-1.9 eV and unique optical, electrical, and magnetic properties. Techniques like cyclic voltammetry (CV), and square wave voltammetry (SWV) were used. Real sample analysis was carried out in real-world samples like different types of soil, vegetables, and water. The electroanalytical sensor showed outstanding catalytic behavior by enhancing the peak current of the 2-phenylphenol with the potential shift to the less positive side compared to the unmodified carbon paste electrode in the presence of pH 7.0 phosphate buffer solution (PB). Throughout the experimental study, double distilled was used. Various electro-kinetic parameters like pH, accumulation time study, scan rate, concentration variation, standard heterogeneous rate constant, and participation of electrons, accumulation time, and transfer coefficient have been studied at WO3/CuO/CPE. The limit of detection was quantified together with the limit of quantification. Possible electrochemical oxidation mechanism of the toxic molecule was depicted. Overall, this research contributes to the field of electroanalytical sensing and offers potential applications in environmental monitoring.

Toward the Real-Time and Rapid Quantification of Bacterial Cells Utilizing a Quartz Tuning Fork Sensor.

The quantitative evaluation of bacterial populations is required in many studies, particularly in the field of microbiology. The current techniques can be time-consuming and require a large volume of samples and trained laboratory personnel. In this regard, on-site, easy-to-use, and direct detection techniques are desirable. In this study, a quartz tuning fork (QTF) was investigated for the real-time detection of E. coli in different media, as well as the ability to determine the bacterial state and correlate the QTF parameters to the bacterial concentration. QTFs that are commercially available can also be used as sensitive sensors of viscosity and density by determining the QTFs' damping and resonance frequency. As a result, the influence of viscous biofilm adhered to its surface should be detectable. First, the response of a QTF to different media without E. coli was investigated, and Luria-Bertani broth (LB) growth medium caused the largest change in frequency. Then, the QTF was tested against different concentrations of E. coli (i.e., 102-105 colony-forming units per milliliter (CFU/mL)). As the E. coli concentration increased, the frequency decreased from 32.836 to 32.242 kHz. Similarly, the quality factor decreased with the increasing E. coli concentration. With a coefficient (R) of 0.955, a linear correlation between the QTF parameters and bacterial concentration was established with a 26 CFU/mL detection limit. Furthermore, a considerable change in frequency was observed against live and dead cells in different media. These observations demonstrate the ability of QTFs to distinguish between different bacterial states. QTFs allow real-time, rapid, low-cost, and non-destructive microbial enumeration testing that requires only a small volume of liquid sample.

Reduced graphene oxide supported MXene based metal oxide ternary composite electrodes for non-enzymatic glucose sensor applications.

Diagnosis and monitoring of glucose level in human blood has become a prime necessity to avoid health risk and to cater this, a sensor's performance with wide linearity range and high sensitivity is required. This work reports the use of ternary composite viz. MG-Cu2O (rGO supported MXene sheet with Cu2O) for non-enzymatic sensing of glucose. It has been prepared by co-precipitation method and characterized with X-ray powder diffraction, Ultraviolet-visible absorption spectroscopy (UV-Vis), Raman spectroscopy, Field emission scanning electron microscopy, High resolution transmission electron microscopy and Selected area diffraction. These analyses show a cubic structure with spherical shaped Cu2O grown on the MG sheet. Further, the electrocatalytic activity was carried out with MG-Cu2O sensing element by cyclic voltammetry and chronoamperometry technique and compared with M-Cu2O (MXene with Cu2O) composite without graphene oxide. Of these, MG-Cu2O composite was having the high defect density with lower crystalline size of Cu2O, which might enhance the conductivity thereby increasing the electrocatalytic activity towards the oxidation of glucose as compared to M-Cu2O. The prepared MG-Cu2O composite shows a sensitivity of 126.6 µAmM-1 cm-2 with a wide linear range of 0.01to 30 mM, good selectivity, good stability over 30 days and shows a low Relative Standard Deviation (RSD) of 1.7% value towards the sensing of glucose level in human serum. Thus, the aforementioned finding indicates that the prepared sensing electrode is a well suitable candidate for the sensing of glucose level for real time applications.

Behavior-based swarm model using fuzzy controller for route planning and E-waste collection.

Nowadays, because of the increase in consumption of electronic equipment and its resource utilization, household e-waste has been generated gradually. The increase in e-waste generation brought environmental burdens as well as a health risk in several nations. The disposal of e-waste in landfills is not recommended due to some poisonous and contaminated chemicals. The improper collection of e-waste leads to a negative impact on human health and also causes air pollution, as well as the long-term effects on the environment. To address such issues, the behavior-based swarm model using a fuzzy controller (BSFC) is proposed for efficient e-waste collection. The proposed algorithm is employed to solve the problem based on routing associated with the time window for the heterogeneous fleet of the e-waste collection vehicle. The approach is provided for the online system that enables the people to request for the collection of e-waste components and also to solve the vehicle's routing problem. The optimization result demonstrates the decrease in the collection cost and also the on-time e-waste collection from the household. The method comprises the implementation of e-waste collection requests in China and India for several urban arrangements of buildings and streets. The proposed approach fetches considerable enhancement in vehicle routing plans for the e-waste collection, counting the positive social impacts for the waste collection, particularly in urban regions.

Fuzzy-based adaptive learning network using search and rescue optimization for e-waste management model: case study.

In recent days, the expansion of e-waste disposal should be increased due to environmental hazards, contamination of groundwater, an unconcerned consequence on marine life, human health, and decrease in the fertility of the soil. The majority of the developing countries are facing massive issues in implementing sustainable e-waste management schemes. The unofficial e-waste management schemes in the region of Chandigarh, India, have become a serious dispute for the government and several stakeholders due to human health and environmental effects. To overcome such shortcomings, this paper proposes an efficient e-waste management system using fuzzy c-means based adaptive optimal neural network. Here fuzzy c-means clustering approach is employed to classify the household e-wastes and adaptive optimal neural network is employed to analyze the relative weights as well as the grading of the obstructions. Here, the financial and economic limitations are regarded as the most important obstructions of e-waste formalization. The sensitivity analysis is carried out to verify the structure robustness and address the bias effect. This study assists the lawmakers to create organized strategies for an efficient e-waste management system. The sustainable set of e-waste management system advances the e-waste management in India quality thereby raising the recycling rate to 40%.

Quartz Tuning Fork Sensor-Based Dosimetry for Sensitive Detection of Gamma Radiation.

This study generally relates to nuclear sensors and specifically to detecting nuclear and electromagnetic radiation using an ultrasensitive quartz tuning fork (QTF) sensor. We aim to detect low doses of gamma radiation with fast response time using QTF. Three different types of QTFs (uncoated and gold coated) were used in this study in order to investigate their sensitivity to gamma radiations. Our results show that a thick gold coating on QTF can enhance the quality factor and increase the resonance frequency from 32.7 to 32.9 kHz as compared to uncoated QTF. The results also show that increasing the surface area of the gold coating on the QTF can significantly enhance the sensitivity of the QTF to radiation. We investigated the properties of gold-coated and uncoated QTFs before and after irradiation by scanning electron microscopy. We further investigated the optical properties of SiO2 wafers (quartz) by spectroscopic ellipsometry (SE). The SE studies revealed that even a small change in the microstructure of the material caused by gamma radiation would have an impact on mechanical properties of QTF, resulting in a shift in resonance frequency. Overall, the results of the experiments demonstrated the feasibility of using QTF sensors as an easy to use, low-cost, and sensitive radiation detector.

NH2-MIL-125(Ti) doped CdS/Graphene composite as electro and photo catalyst in basic medium under light irradiation.

The development of active electrocatalysts and photocatalysts for hydrogen evolution reaction (HER) and for environmental remediation is a huge challenge. Research is still underway on the development of low-cost catalytic materials with appreciable efficiency for HER. In the present study, a composite of metal organic framework (MOF) with CdS and graphene (NH2-MIL-125(Ti)/CdS-graphene) composites were developed with different loadings of graphene material via solvothermal technique. Further the electrocatalytic activity of the synthesized catalysts were investigated for HER and photocatalytic degradation of dye. Results show that the synthesized catalyst with a less amount of graphene was more active. HER results showed a less Tafel slope of 70.8 and 61.9 mVdec-1 with 15.6 mA/cm2 and 15.46 mA/cm2 current densities under light on and off conditions. Further the dye degradation activity of the synthesized catalysts was tested with Rhodamine B dye and results showed that the catalyst showed excellent activity for low weight loading of graphene with a degradation efficiency of 95 % and followed pseudo first order kinetic model. Overall results showed that the synthesized composites are promising for HER and photocatalytic applications.

Au integrated 2D ZnO heterostructures as robust visible light photocatalysts.

Integration of semiconducting nanostructures with noble metal nanoparticles are turning highly desirable for cost efficient energy and environmental related applications. From this viewpoint, we report on a facile aqueous synthesis of polymer capped gold (Au) nanoparticles on free standing 2D layered structures of zinc oxide (ZnO) to result with ZnO/Au nanocomposites. Concentration of Au nanoparticles were observed to promote the preferential growth of ZnO along the (002) wurtzite plane. The ZnO/Au structures and their morphological dissemination was noted to be of few. This flake like structure was also noted to be greatly influenced by the concentration of Au in the colloidal blend. Optical band edge transformations noted in the absorption spectra across the lower wavelength region and the shift in surface plasmon resonance (SPR) towards the red region of the visible spectrum signify the improved absorptivity of the heterostructures along the visible spectrum. These heterostructures exhibited remarkable visible light driven photocatalytic activity (99% efficiency) on par with pristine ZnO. The findings also attest this new class of composite structures to open up new openings in diversified solar energy conversion related functions.

Multi-walled carbon nanotube-based nanobiosensor for the detection of cadmium in water.

Industrial and agricultural processes have led to the prevalence of cadmium in the ecosystem. A successive build-up of cadmium in food and drinking water can result in inadvertent consumption of hazardous concentrations. Such environmental contamination of cadmium can pose a substantial threat to human and animal life. In humans, it is known to cause hypertension, cardiovascular diseases, DNA lesions, inhibition of DNA repair protein or disturb the functioning of lung, liver, prostate and kidney. The development of a reliable method for Cd (II) ions detection would reduce the exposure and complement existing conventional methods. In this study, a DNA based electrochemical method is employed for the detection of Cd (II) ions using ethyl green (EG) and multi-walled carbon nanotube (MWCNT). Glassy carbon electrode (GCE)/MWCNT forms the working electrode for differential pulse voltammetry (DPV) analysis for the detection of Cd (II) ions. The dsDNA is immobilized onto the working electrode. The indicator dye EG, preferably binds to ssDNA and its reduction peak current is noticeably less in the presence of dsDNA. The Cd (II) ions after interacting with dsDNA, unwinds the dsDNA to ssDNA, upon which the EG molecules bind to ssDNAs, giving a higher reduction peak current. The difference in the reduction peak currents in the presence and absence of Cd (II) ions is proportional to its concentration. The linear detection range achieved in this method is 2 nM-10.0 nM with a sensitivity of around 5 nA nM-1 and the limit of detection is 2 nM, which is less than the permissible limit of WHO for human exposure. This study considerably broadens the possible application of multi-walled carbon nanotube modified electrodes as biosensors and holds prospects for the detection of other heavy metals in environmental samples.