Hole transport materials stabilize and boost perovskite solar cell efficiency. In depth, understanding of the structure-property relationship will help in the rational design of efficient HTM for PSCs. In the present work, we have theoretically designed five efficient hole transport molecules based on triphenylamine as acceptor units. Their architecture is based on donor-acceptor-donor style using various core molecules e.g. thiophene, benzotrithiophene (BTT), benzo-2,1,3-thiadiazole (BT). Various p-linkers such as 3,4-ethylenedioxythiophene (EDOT), benzothiadiazole and thiophene are used for connecting both ends. Optical properties, electronic properties, hole transport behaviour, and photovoltaic properties are computed for the designed molecules based on DFT and TD-DFT methods on the basis of B3LYP hybrid functional. The geometries, ESP distribution, dipole moment, reorganization energies, UV-spectrum, and frontier molecular orbitals (FMOs) were discussed to study the electronic properties of the designed molecules. And the hole electron distribution, absorption spectra, Light harvesting Efficiency (LHE), alignment of the density of states along with transition density matrix, binding, and excitation energy were discussed to study the optical properties. This investigation provides an understanding of how the structure and properties of these molecules are related and how they can be modified to obtain desirable properties. This work will help design novel, efficient HTM molecules in the future by computational modelling and later leading to the fabrication of PSC devices with these types of HTMs.

The widespread use of the pharmaceutical compound diclofenac, its toxic effects and environmental persistence, together with its inefficient removal by conventional water/wastewater treatment processes, have led to major environmental and public health concerns. Adsorption is one of the most popular advanced techniques due to its numerous advantages, such as high removal efficiency and selectivity, as well as its economical and environmental sustainability. Three-dimensional printing makes the custom production of custom-made, complex-shaped adsorbents possible. A vat photopolymerization technique was employed in order to achieve the layer-by-layer solidification of a powdered activated carbon/photopolymer suspension into the desired shape, followed by its amine functionalization. The adsorbent was characterized by FTIR, SEM, N₂ porosimetry and contact goniometry. Batch adsorption experiments in simulated diclofenac wastewater were conducted. The final pollutant concentration was spectrophotometrically determined. The successful synthesis of the composite adsorbent was confirmed. The optimum pH value was found to be 5, while kinetic and isothermal experiments were conducted at pH=7, as it corresponds to that of the secondary treated diclofenac-containing wastewater effluents. The optimum contact time was 24h. Isothermal data revealed that the material adsorption capacity decreases with temperature. The optimum solution pH value of the adsorbent’s regeneration process was found to be alkaline. Post-printing surface functionalization by diethylenetriamine increases the adsorbent’s hydrophilicity and adsorption efficiency. Post-printing diethylenetriamine modification of the adsorbent increases its diclofenac removal efficiency by 7-fold, but it also alters its surface from hydrophobic to hydrophilic. Overall, 3D printing via photopolymerization can be successfully employed for the production of activated carbon–polymer composites as efficient reusable adsorbents for diclofenac removal from wastewater.

Printed electronics (PE) are rapidly growing, especially in wearable sensors, smart textiles, and IoT devices. Conductive inks, essential for the fabrication of PE, must be highly conductive, cost-effective, biocompatible, easy to prepare, and less viscous. Conductive inks comprise of a conducting material (metals like silver, gold, copper, or carbon-based alternatives like graphite, graphene, and carbon nanotubes), a binder, and a solvent. In this work, a water-based graphite conductive ink is developed using graphite as a conductive material, corn starch powder (non-toxic and biodegradable) as a binder, and distilled water as a solvent. Firstly, corn starch powder is added to distilled water, which is heated up to 100 °C and stirred continuously until a homogeneous gel-like mixture is formed. After cooling the mixture, graphite powder is added to it, and stirred for an hour at 450 rpm to obtain the ink. To check the conductivity, the ink is brush-painted on a paper substrate with a dimension of 20 mm x 10 mm, and the result shows a low ohmic resistance of ~ 560 Ω, confirming the highly conductive nature of the ink. Additionally, thermogravimetric analysis (TGA) is performed on the prepared ink to evaluate its thermal stability, and a very strong X-ray diffraction (XRD) peak obtained at 2θ° = 26.5426°, a small peak at 2θ° = 54.6145°, along with a few other small peaks, confirms the presence of graphite with corn starch. Thus, this conductive ink can be used for PE owing to its affordability, biocompatibility, and ease of preparation.

Molybdenum disulfide (MoS₂) has been regarded as a promising material for solving the current fossil fuel shortage and environmental problems due to its remarkable semiconducting and photocatalytic properties. However, monolayer MoS₂ has attracted most of the scientific interest, leaving its multilayer counterpart neglected. Multilayer or bulk MoS₂ has its own advantages, e.g., low cost and restricted recombination of photoexcited electrons and holes due to its indirect band. The major barrier for its application is the large proportions of inert basal planes. Given this, activating the inert sites of multilayer MoS₂ would develop a practical candidate for the photocatalyst family. Efforts have been devoted to introducing S vacancies through various sophisticated techniques; however, most of these are not applicable in real-life applications.

In our recent work, we proposed a nanofabrication strategy to join transition metal nanoparticles to MoS₂ via silver buffer layers [1,2]. Typically, nickel nanoparticles up to 200 nm could be chemically attached to both the edges and basal planes of multilayer MoS₂ through this method, leading to activated MoS₂ with greatly enhanced photocatalytic hydrogen evolution efficiency. Further investigation has also revealed its feasibility for photodegradation of organic pollutants in natural water. Therefore, hydrogen production and water purification could be achieved simultaneously. Based on high-resolution XPS analysis, we believe that the successful nickel doping and high photocatalytic performance can be attributed to the effective bonding between Ni and MoS₂, which serves as an expressway for electrons crossing between the semiconducting side and the active metallic sites.

[1] X. Shi, M. Zhang, X. Wang, et al. Nickel nanoparticle-activated MoS₂ for efficient visible light photocatalytic hydrogen evolution. Nanoscale, 2022, 14, 8601−8610.

[2] X. Shi, S. Posysaev, M. Huttula, et al. Metallic contact between MoS₂ and Ni via Au nanoglue. Small, 2018, 14, 1704526.

The rapid development of nanotechnology has significantly transformed various industrial processes associated with food production (e.g., through the introduction of smart and active packaging, nanosensors, nanopesticides, and nanofertilizers). This study focuses on two nanoparticles widely used in the food industry, titanium dioxide (TiO₂-NPs) and zinc oxide (ZnO-NPs), and their effects on human cells. Thus, the cytotoxicity of TiO₂-NPs (commercially acquired; spherical shape with an average size of 298.4 nm and a PDI of 0.248) and ZnO-NPs (synthesized in the laboratory; spherical-like shape with an average size of 339.9 nm and a PDI of 0.590) to a human colon cancer cell line (HCT116) was studied, assessing cellular metabolic activity, as an indicator of cell viability, through the MTT assay. Overall, exposure to ZnO-NPs induced a dose-dependent reduction in cell viability, with half maximal inhibitory concentration (IC₅₀) values of 10.4 mg/L, 8.8 mg/L, and 7.7 mg/L at 24, 48, and 72h, respectively. In contrast, TiO₂-NPs did not induce significant differences in cell viability across the same time points. These findings highlight the differential cytotoxic effects of ZnO-NPs and TiO₂-NPs on colon cancer cells, suggesting a need for the careful consideration of ZnO-NPs in food applications, due to their potential health risks. Overall, this study provides crucial insights into the biological interactions of these nanoparticles, highlighting the importance of thorough safety evaluations in their use within the food industry.

Introduction

Utilizing organic biowaste to produce nanoparticles has become of great interest in the field of nanotechnology. Nanomaterials produced through this green route are non-toxic, and the process is environmentally friendly. In this project, we synthesized stable and well-defined silver nanoparticles and nanocomposite films using organic biowaste such as banana peels, chikoo peels, and lemon peels. The synthesis methodology and their application as antibacterial and catalytic agents were investigated.

Method

The formation of silver nanoparticles was achieved using biowaste extracts as reducing and stabilizing agents. Sodium alginate–polyvinyl alcohol–silver nanocomposites were prepared by crosslinking using glutaraldehyde. All the materials were characterized by UV-Vis spectroscopy and electron microscopy. Their antibacterial properties were assessed against Staphylococcus epidermidis, Staphylococcus aureus, and Eschericia coli.

Results

The color change to black with the addition of NaOH indicated the formation of silver nanoparticles. The nanoparticles exhibited a strong plasmon resonance (SPR) peak at around 400 nm, confirming their presence. The peak was sharp and narrow, indicating low polydispersity. The nanocomposite films were effective against the bacteria tested, especially Staphylococcus epidermidis.

Conclusion:

The green synthesis of silver nanoparticles using biowaste yielded promising results, such as the creation of flexible films. The re-use and application of the nanocomposite films in the proliferation of fibroblast cells are currently in progress.

Introduction

Infectious diseases caused by potent microbes, the recent Covid-19 medical crisis, and increase in antibiotic resistant pathogens are serious medical and scientific challenges. These challenges pose a huge impact on the economy and health care systems of any country. There is an urgent need to development functional materials for immediate decontamination of surfaces. In this project, we have successfully fabricated a peelable nanocomposite hydrogel based on polyvinyl alcohol (PVA), sodium alginate and silver nanoparticles (synthesized using a green method). The hydrogel film was crosslinked with glutaraldehyde and zinc acetate and exhibited good antibacterial properties.

Methods

Silver nanoparticles reinforced peelable hydrogel films and slabs comprising of PVA and sodium alginate were fabricated through in situ formation of nanoparticles using extracts of three different medicinally important plants such as Yerba mate, Hibiscus, and Matcha green tea. PVA and sodium alginate were crosslinked using glutaraldehyde (1 wt%), and zinc acetate solution, respectively. The physical and antibacterial properties of the prepared films were evaluated using established methods.

Results

The resulting hydrogels were tough, and the films were peelable and flexible. A strong surface plasmon resonance (SPR) peak around 400 nm confirmed the presence of silver nanoparticles in the hydrogel. The hydrogels exhibited considerable swelling capacity and the equilibrium water capacity was evaluated.

Conclusion and Work in-progress

A decontaminating hydrogel (in the form of slabs and films) composed of PVA and sodium alginate containing green synthesized silver nanoparticles were successfully prepared. The silver nanoparticles were prepared by ins situ chemical reduction using the extracts of medicinally important plant products. The presence of phytochemicals and silver nanoparticles had a synergistic effect on the antibacterial properties of the hydrogel. The mechanical properties of the films are currently being explored.

The researchers paid increasingly more attention to the creation of materials which would be cheap, have good sensitivity and be, environmentally benign. Zinc oxide (ZnO) has multiple applications due to its unique physical, chemical, and optoelectronic properties. This makes it ideal for usage on solar cells, light-emitting diodes, and gas sensors. There is increasing interest in ZnO nanostructures especially the one-dimensional forms since they can easily and rapidly respond to external influences of temperature and humidity. High-quality ZnO nanowires are of great scientific interest, however, there is no universal method to produce them in a simple and economical way with all important parameters accurately specified.

The objective of this study to produce more oriented and purer one-dimensional ZnO nanostructures using a simple and fast method, in this case the synthesis of ZnO Nanowires. Synthesis of ZnO nanowires was accomplished in a two-step process. The initial step involved applying a seed layer onto the surface of the substrate that was aimed to anchor ZnO molecules. The molecular structures were observed using Atomic Force Microscopy (AFM). Nanowires’ second step included growing the structures with the use of a hydrothermal method, where the size of the synthesized ZnO nanowires was 100-150 nm.

The findings show that this approach leads to the successful fabrication of ZnO nanowires with great uniformity, large surface area and well-defined geometric shapes. The nanowires are also shown to possess good structural as well as chemical integrity, establishing their application in the domains of optoelectronic devices and gas sensors. In addition, the hydrothermal method is simple and reliable, and ZnO nanowires appear to be of good quality; therefore, this method is low-cost and easily up-scaled with great potential for industrial applications.

Electrochemical nitrogen reduction to ammonia (NRR) is a green alternative to the Haber–Bosch process. This reaction is carried out at room temperature and pressure but has low efficiency due to the difficulties associated with breaking the nitrogen triple bond. It is possible to replace the traditional reaction with a nitrate reduction reaction (NO₃RR). In addition, achieving electrochemical nitrate reduction (NO₃⁻) to ammonia (NH₃) is an urgent and important task from the point of view of economics and environmental protection. The unique electronic structure and large reserves of transition metals have led to transition metal-based catalysts being widely studied in the field of the electrochemical conversion of NO₃⁻ to NH₃. Copper-based catalysts have a special electronic structure and exhibit the highest activity and selectivity among single-component metal catalysts for the NO₃RR electrochemical reaction. The unique electronic configuration of copper on the surface promotes adsorption and electron transfer between nitrate ions, which can effectively inhibit the HER (hydrogen evolution reaction) and promote the initial conversion of NO₃⁻ to NH₃. In this study, the catalytic efficiency of copper electrodeposited catalysts in the NO₃RR reaction was studied. The conversion of NO₃⁻ to NH₃ involves a complex transfer of eight electrons and many intermediates. The reaction was carried out at a controlled potential, which was previously established using the method of linear voltammetry. The catalysts were represented by copper and graphite substrates with electrodeposited copper particles on the surface. It was shown that the catalysts have a certain level of catalytic activity. Calculations of Faradaic efficiency showed values of up to 29%. All the electrocatalysts were characterized by SEM, EDX, and other modern methods. This study is a composite, but at the same time complete, part of other work focused on the synthesis of new catalysts for NO₃RR and NRR.

Introduction

Bacteria and toxicants continue to threaten our health and pollute our environment. Eradicating those substances would lead to better health. Synthesizing selenium nanoparticles and incorporating them into solid supports is a milestone toward better health and hygiene due to their antimicrobial and catalytic properties. In this project, we have synthesized bovine serum album (BSA) capped silver nanoparticles using ascorbic acid, and polymer supported beads. The materials exhibited good antibacterial and catalytic properties.

Method

Selenium nanoparticles were synthesized by a reduction reaction using two core components, ascorbic acid (reductant) and sodium selenite, by two methods: First, the addition of ascorbic acid to sodium selenite drop-wise, then bovine serum albumin (BSA), a stabilizer to prevent sedimentation. It was tested by spectrometry. Secondly, beads were formed using sodium alginate and calcium chloride, which were added to the core components. In a UV-VIS spectrometer, the beads catalyzed the reaction with Congo red - a toxic dye - and NaBH4. Additionally, both methods were tested for their antibacterial properties on Staphylococcus epidermidis, Staphylococcus Aureus, and E.Coli.

Results

The formation of selenium nanoparticles was confirmed by UV-Vis spectroscopy. The particles were stable against aggregation due to the capping of BSA. The nanocomposite beads were spherical with porous morphology, and were effective in the degradation of a model dye Congo red. The beads are reusable with no appreciable decrease in degradation efficiency.

Conclusion

The nanoparticles and the nanocomposite beads were effective against bacteria. The beads were reusable and had enhanced catalytic activity against Congo red, showing promise for decontamination of water including hospital waste water.