Ag Nanomaterials Research Articles

Toxicokinetics and toxicodynamics of Ag nanomaterials (NM300K) in the soil environment–impact on Enchytraeus crypticus (Oligochaeta)

Silver (Ag) is one of the most used elements in the nanomaterials (NMs) form, which upon release to the environment can be harmful to organisms. We compared the toxicokinetics (TK) and toxicodynamics (TD) of Ag from AgNO3 (0, 15, 45, 135, 405 mg Ag/kg soil) and AgNM300K (0, 75, 150, 300, 600, 1200 mg Ag/kg soil) in the model organism Enchytraeus crypticus. Organisms were exposed in LUFA 2.2 soil, and besides body Ag concentrations, survival and reproduction were determined, in a time series (for 21 days). In the soil, the available (CaCl2 extractable) Ag fraction from Ag NM300K increased from 0 to 21 days but did not consistently change for AgNO3. Internal concentrations reached equilibrium in most exposures to both Ag forms. The organisms were able to internalize and eliminate Ag, but less when exposed to Ag NM300K. The overall uptake rate constants for Ag from AgNO3 and Ag NM300K exposures were 0.05 and 0.06 kg soil/kg organism/day, respectively, the elimination rate constants 0.2 and 0.1 day−1, respectively. For AgNO3 the median lethal concentrations decreased steadily with time, while for Ag NM300K they remained constant during the first 10 days of exposure followed by a 2-fold decline in the last 7 days. The 21-d LC50s for both Ag forms were similar but the LC50inter (based on internal concentrations) were 63 and 121 mg Ag/kg body DW (Dry Weight) for AgNO3 and Ag NM300K, respectively, showing higher toxicity of AgNO3. These results show the importance of assessing time to toxicity, a relevant factor in toxicity assessment, especially for NMs.

Facile synthesis of gold nanocages with silver nanocubes templates dual metal effects enabled SERS imaging and catalytic reduction.

Silver (Ag) nanomaterials featuring a cubic shape particularly represent supreme class of advance nanomaterials. This work explored a new precursor and its effect on morphological features of silver (Ag) nanocubes (NCs) serving as sacrificial templates for facile synthesis of gold NCs. The AgNCs were initially prepared utilizing sodium thiosulphate (Na2S2O3) as relatively stable S2- producing species along with a soft etchant source KCl. The effects of different potassium halides were evaluated to grasp control over seed mediated growth of Ag nanocubes. Taking the advantages of dual metallic properties, Ag@4MBA@AuNCs nanostructure was synthesized using 4-mercaptobenzoic acid (4MBA) as a Raman reporter molecule. This nanostructure showed 1010-times enhancement in surface enhanced Raman scattering (SERS) signal, leading to a highly sensitive imaging probe for the detection of even three breast cancer cells (MCF-7 cells) in vitro. Subsequently, the oxidative nanopeeling well accompanied by incorporation of Au/Ag alloy nanoparticles on AuNCs corona assembly was achieved, which facilitated the catalytic reduction of toxic nitrophenol to eco-friendly aminophenol. Such sophisticated and engineered nanoassemblies possess broad applications in bioanalysis.

Rod-to-sphere elemental reconstruction of biocompatible Ag2Te-Ag4.53-Te3 nanoparticles for triple negative breast cancer photo-nano-therapy.

Silver nanoparticles (AgNPs) continue to be applied to agricultural and medical applications because of their antibacterial and antifungal effects. However, AgNPs are vulnerable to poisoning by oxidation or sulfidation, and unintentional toxicity can occur via leaching. Therefore, ensuring the stability of AgNPs for practical applications is considered an important requirement. In this study, we propose the solvothermal galvanic replacement of a Te nanorod (TeNR) template with a Ag precursor to manufacture highly stable and biocompatible Ag-Te nanoparticles (AgTeNPs). In addition to their high stability, AgTeNPs composed of Ag2Te-Ag4.53Te3 were evaluated as a nanotherapeutic agent enabled by their selective toxicity through metabolic degradation in breast cancer cells. It has been demonstrated that combinatorial treatment with hyperthermic cancer-cell ablation through photothermal conversion provides an effective cancer treatment in vitro and in vivo. The discovered new biocompatible Ag nanomaterials with innate anticancer effects are expected to be applied to various application fields.

A comparative study of the catalytic activity between Ag nanoparticles and Ag flower-like particles synthesized by the Sedum praealtum aqueous extract

This work shows that using Sedum praealtum extract, silver nanoparticles (AgNPs) and flower-like silver self-assemblies (AgFLs) can be synthesized by varying only the concentration of AgNO3. In addition, the comparison of its catalytic activity on the degradation of the methylene blue dye (MB) was evaluated. SEM showed spherical AgNPs of ∼15 nm at 5 mM (AgNO3) concentration, and AgFLs are formed at 10 mM (AgNO3). XRD patterns confirmed the fcc crystal structure of the materials. FTIR spectroscopy determined that glycoside compounds are the main participants as reducing agents, stabilizers, and binders. UV-Vis spectroscopy confirmed the obtaining of Ag nanomaterials through the characteristic resonance band of the surface plasmon (RSP). In addition, the value of the band-gap was determined to measure the catalytic activity in the degradation of MB. The photocatalytic activity was mainly favored by smaller sizes of AgNPs, over the texture and surface porosity of AgFLs. However, it is independent of the morphology, and the use of an external reducing agent (NaBH4) since a 90% degradation is obtained after 24 h of reaction due to the combined action of photocatalysis and dye adsorption.

Comparison of In Vitro Approaches to Assess the Antibacterial Effects of Nanomaterials.

The antibacterial properties of nanomaterials (NMs) can be exploited in a range of consumer products (e.g., wound dressings, food packaging, textiles, medicines). There is also interest in the exploitation of NMs as treatments for infectious diseases to help combat antibiotic resistance. Whilst the antibacterial activity of NMs has been assessed in vitro and in vivo in numerous studies, the methodology used is very varied. Indeed, while numerous approaches are available to assess the antibacterial effect of NMs in vitro, they have not yet been systematically assessed for their suitability and sensitivity for testing NMs. It is therefore timely to consider what assays should be prioritised to screen the antibacterial properties of NMs. The majority of existing in vitro studies have focused on investigating the antibacterial effects exhibited by silver (Ag) NMs and have employed a limited range of assays. We therefore compared the antibacterial effects of copper oxide (CuO) NMs to Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis at various concentrations (12.5-200 µg/mL) using a battery of tests (well and disc diffusion, plate counts-time-kill method, optical density measurement-OD, Alamar Blue and live/dead viability assays, and quantitative polymerase chain reaction). CuO NMs were most toxic to B. subtilis and E. coli, while P. aeruginosa was the least sensitive strain. All assays employed detected the antibacterial activity of CuO NMs; however, they varied in their sensitivity, time, cost, technical difficulty and requirement for specialized equipment. In the future, we suggest that a combination of approaches is used to provide a robust assessment of the antibacterial activity of NMs. In particular, we recommend that the time-kill and OD assays are prioritised due to their greater sensitivity. We also suggest that standard operating protocols are developed so that the antibacterial activity of NMs can be assessed using a harmonised approach.

Functionalized Silver and Gold Nanomaterials with Diagnostic and Therapeutic Applications.

The functionalization of nanomaterials with suitable capping ligands or bioactive agents is an interesting strategy in designing nanosystems with suitable applicability and biocompatibility; the physicochemical and biological properties of these nanomaterials can be highly improved for biomedical applications. In this context, numerous explorations have been conducted in the functionalization of silver (Ag) and gold (Au) nanomaterials using suitable functional groups or agents to design nanosystems with unique physicochemical properties such as excellent biosensing capabilities, biocompatibility, targeting features, and multifunctionality for biomedical purposes. Future studies should be undertaken for designing novel functionalization tactics to improve the properties of Au- and Ag-based nanosystems and reduce their toxicity. The possible release of cytotoxic radicals or ions, the internalization of nanomaterials, the alteration of cellular signaling pathways, the translocation of these nanomaterials across the cell membranes into mitochondria, DNA damages, and the damage of cell membranes are the main causes of their toxicity, which ought to be comprehensively explored. In this study, recent advancements in diagnostic and therapeutic applications of functionalized Au and Ag nanomaterials are deliberated, focusing on important challenges and future directions.

High-performance aqueous rechargeable Zn-Ag and Zn-Ag/air hybrid batteries based on Ag nanobelts as highly stable bifunctional electrode

The Zn-Ag and Zn-Ag/air hybrid batteries are challenged by the low conductivity and capacity of Ag electrode materials. How to further optimize and tune the surface electronic structure of Ag nanomaterials has become an important topic in the improvement of Ag electrode materials. Herein, the silver nanobelts (Ag NBs) materials were prepared by a fast and simple redox replacement reaction. The special nanobelts structure, with the key surface features of the gully-like morphology, raised Ag mounds and superlattice fringes, are beneficial to tune the surface electron structure and thereby increase the conductivity and electrochemical performance of Ag NBs. As a consequence, the assembled Zn-Ag battery exhibits favorable electrochemical performance in view of the specific capacity of 380.9 mAh gAg−1. In addition, the hybrid Zn-Ag/air battery shows two-step voltage plateaus of 1.83 and 1.55 V in the Zn-Ag reaction, as well as a voltage plateau of 1.23 V corresponding to the Zn-air reaction. The hybrid battery maintains a high energy efficiency of 76.9% and high rate capabilities, demonstrating an excellent energy-saving feature of this battery. The insights gained from this work may be beneficial for designing the highly-efficient Ag catalysts for electrochemical energy storage.

Avoidance Behaviour of Six Collembolan Species Shows Species-Specific Sensitivity-Impact of Ag NM300K.

Although standard testing guidelines use a species as a representative surrogate, species-specific sensitivity is well-known. The aim of this study was to investigate the species-specific difference in avoidance behaviour among Collembola species exposed to silver (Ag) nanomaterials (NM) (Ag NM300K). The avoidance test was performed with Folsomia candida, an international standard species in laboratory tests, and five widely distributed species with different life history traits, commonly used in small multispecies systems (Folsomia fimetaria, Proisotoma minuta, Mesaphorura macrochaeta, Protaphorura fimata and Ceratophysella denticulata). There was higher avoidance in euedaphic species, such as F. candida and F. fimetaria, compared to the epiedaphic species C. denticulata, which showed the least avoidance behaviour. An explanation may be that euedaphic species (living in deeper soil layers) are more directly exposed within the soil pores and have developed a pronounced avoidance behaviour. In contrast, species living on the surface are likely less directly exposed and hence only avoid at higher total concentrations. Additionally, difference in cuticula between the groups, providing different degrees of protection against exposure, can explain the different behaviours. The present results highlight the importance of biodiversity for the ecosystem and raise awareness on species sensitivity.

A comparison of silver nanoparticles made by green chemistry and femtosecond laser ablation and injected into a PVP/PVA/chitosan polymer blend

Due to their antibacterial effect, silver nanoparticles (AgNPs) are attracting more and more attention for various applications in biomedicine. The production of nanomaterials from organometallic precursors requires the use of a capping agent that acts as a stabilizer and provides colloidal stability while preventing agglomeration and excessive growth. In this research, we studied the optical properties and antibacterial activity of AgNPs loaded in a blend of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), and chitosan, which were used as capping agents to control the shape and size of the nanoparticles and to impart stability to the synthesized Ag nanomaterials. Characterization studies showed that the blend provides a uniform and controlled distribution of AgNPs inside the polymeric matrix without the addition of any more stabilizers. The mean particle size for green and laser-ablated AgNPs was found to be ~ 50 nm according to transmission electron microscopy (TEM) studies. Fourier transform infrared (FTIR) studies showed the presence of characteristic main peaks corresponding to the vibrational groups which characterize the prepared samples. The interactions between the AgNPs and the blend were marked by changes in the intensity of vibrational peaks and spectral positions. X-ray diffraction (XRD) confirmed the crystallographic modification within the PVP/PVA/chitosan matrix because of AgNPs filling. The change in the absorbance has been studied with the help of measured ultraviolet–visible spectroscopy (UV–Vis.) and therefore the optical band gap was calculated. The filling of AgNPs in the blend shows a broad peak at 427 nm because of the phenomenon of surface plasmon resonance (SPR) and its intensity increases with increasing filler concentration. The blend and the Ag nanocomposite showed remarkable antibacterial activity and caused a significant decrease in microbial growth (Escherichia coli) in 24 h. These outcomes demonstrate the suitability and promise of the nanocomposites for various applications, including biomedical labels, sensors, and detectors.

Numerical computation for the dual solution of Sisko hybrid nanofluid flow through a heated shrinking/stretching porous disk

The behaviour of shear-thinning and shear-thickening fluids in magnetohydrodynamic flow is revealed in this work, which includes the substantial influence of a Sisko hybrid nanofluid across a permeable radially stretching/shrinking disk. The Sisko hybrid nanofluid is synthesised in the presence of MgO (magnesium-oxide) and Ag (Silver) nanomaterials in the water. The flow problems are arranged in the format of partial differential equations (PDEs) under the influences of the magnetic field, heat absorption/generation, and chemical reaction, which are subsequently transformed into a system of dimensionless ordinary differential equations (ODEs) using appropriate variables. The parametric continuation approach is used to computationally address the modified dimensionless ODEs. The consequences of physical constraints versus energy, velocity, and mass profile are also elaborated. When the influence of suction dominates around 10% in the boundary layer, there is a large increase in the rate of heat transmission, about 13.2%. As a result, as compared to a conventional fluid, the new form of hybrid nanofluid has a higher energy transition rate and thermal conductivity. Furthermore, the drawings reveal that the variation in the quantity of nanoparticles (Nps) and magnetic strength prevents the detachment of the boundary layer.

Pre-validation of a reporter gene assay for oxidative stress for the rapid screening of nanobiomaterials.

Engineered nanomaterials have been found to induce oxidative stress. Cellular oxidative stress, in turn, can result in the induction of antioxidant and detoxification enzymes which are controlled by the nuclear erythroid 2-related factor 2 (NRF2) transcription factor. Here, we present the results of a pre-validation study which was conducted within the frame of BIORIMA (“biomaterial risk management”) an EU-funded research and innovation project. For this we used an NRF2 specific chemically activated luciferase expression reporter gene assay derived from the human U2OS osteosarcoma cell line to screen for the induction of the NRF2 mediated gene expression following exposure to biomedically relevant nanobiomaterials. Specifically, we investigated Fe3O4-PEG-PLGA nanomaterials while Ag and TiO2 “benchmark” nanomaterials from the Joint Research Center were used as reference materials. The viability of the cells was determined by using the Alamar blue assay. We performed an interlaboratory study involving seven different laboratories to assess the applicability of the NRF2 reporter gene assay for the screening of nanobiomaterials. The latter work was preceded by online tutorials to ensure that the procedures were harmonized across the different participating laboratories. Fe3O4-PEG-PLGA nanomaterials were found to induce very limited NRF2 mediated gene expression, whereas exposure to Ag nanomaterials induced NRF2 mediated gene expression. TiO2 nanomaterials did not induce NRF2 mediated gene expression. The variability in the results obtained by the participating laboratories was small with mean intra-laboratory standard deviation of 0.16 and mean inter laboratory standard deviation of 0.28 across all NRF2 reporter gene assay results. We conclude that the NRF2 reporter gene assay is a suitable assay for the screening of nanobiomaterial-induced oxidative stress responses.

Hazard identification of nanomaterials: In silico unraveling of descriptors for cytotoxicity and genotoxicity

Hazard identification and safety assessment of the huge variety of nanomaterials (NMs), calls for robust and validated toxicity screening tests in combination with cheminformatics approaches to identify factors that can drive toxicity. Cytotoxicity and genotoxicity of seventeen JRC repository NMs, derived from titanium dioxide, zinc oxide, silver and silica, were tested in vitro using human lung alveolar epithelial cells A549. Cytotoxicity was assessed with the AlamarBlue (AB) and colony forming efficiency (CFE) assays, and genotoxicity by the enzyme-linked version of the comet assay. Nanoparticle tracking analysis (NTA) was used to measure size of the NMs in stock and in cell culture medium at different time points. Categorization and ranking of cytotoxic and genotoxic potential were performed (EU-NanoREG2 project approach). Descriptors for prediction of NMs toxicity were identified by quantitative structure-activity relationship (QSAR) analysis. Our results showed that ZnO NMs (NM-110 and NM-111), and Ag NMs (NM-300K and NM-302) were cytotoxic, while the TiO2 and SiO2 NMs were non-cytotoxic. Regarding genotoxicity, TiO2 NM-100, ZnO NM-110, SiO2 NM-203 and Ag NM-300K were categorized as positive. Cheminformatics modeling identified electron properties and overall chemical reactivity as important descriptors for cytotoxic potential, HOMO-LUMO energy parameter, ionization potential, pristine size for the NMs´ genotoxic potential, and presence of surface coating as descriptor for induction of DNA oxidized base lesions.

Tuning Electrochemical Properties of Silver Nanomaterials by Doping with Boron: Application for Highly Non‐enzymatic Sensing of Hydrogen Peroxide

AbstractA new type of enzyme‐free electrochemical sensor with B−Ag nanomaterials as electrocatalyst was designed. The obtained nanomaterials were characterized by transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and powder X‐ray diffraction (XRD). The results show that B was successfully doped onto the surface of Ag, which reduces the particle size of Ag nanoparticles and expands the crystal plane spacing of Ag, therefore making Ag display larger specific surface area and faster electron transfer rate. The new enzyme‐free electrochemical sensor based on B−Ag shows high electrocatalytic activity for the H2O2 reduction and exhibits excellent sensing performance for the electrochemical detection of H2O2 with a wide range from 0.01 mM to 5.55 mM, a high sensitivity of 68.3 μA⋅mM−1cm−2 and a low detection limit of 0.04 μM. This study demonstrated B−Ag is a promising sensing material for electrochemical enzyme‐free sensors.

Synthesis of Xylan-Click-Quaternized Chitosan via Click Chemistry and Its Application in the Preparation of Nanometal Materials.

For the high-valued utilization of hemicelluloses and for realizing the controllable synthesis of NPs, this paper’s aim is to combine xylan, chitosan and nanometal materials at the same time. In this research study, firstly, propargyl xylan was synthesized via nucleophilic substitution reaction between xylan and propargyl bromide in NaOH solution. On the other hand, a tosyl group was introduced onto the 6th position of synthesized quaternized chitosan (QCS), and the azide group replaced the tosyl group to obtain 6-amido-QCS (QCS-N3). The synthesis conditions of the above reactions were optimized. Subsequently, the novel xylan-click-QCS polymer was obtained via click reaction between terminal alkyne groups on the xylan chains and azide groups on QCS. Then, AgNPs and AuNPs were synthesized by adopting the xylan-click-QCS polymer as the reducing and stabilizing agent, and the reaction conditions were optimized to obtain well-dispersed and highly stable nanoparticles. There were two kinds of Ag nanomaterials, with diameters of 10~20 nm and 2~5 nm, respectively, indicating the formation of Ag nanoclusters, except for Ag nanoparticles, in this reaction. The diameter of the synthesized AuNPs was 20~30 nm, which possessed a more uniform size distribution. The Ag nanoclusters with a smaller size (2~5 nm) could inhibit MCF-7 cell proliferation effectively, indicating their application potential in cancer therapy. The study gives a new approach to the high-value utilization of biopolymers.

Biogenic Silver Nanoparticles as a Stress Alleviator in Plants: A Mechanistic Overview.

Currently, the growth and yield of crops are restrained due to an increase in the occurrence of ecological stresses globally. Biogenic generation of nanomaterials is an important step in the development of environmentally friendly procedures in the nanotechnology field. Silver-based nanomaterials are significant because of their physical, chemical, and biological features along with their plentiful applications. In addition to useful microbes, the green synthesized Ag nanomaterials are considered to be an ecologically friendly and environmentally biocompatible method for the enhancement of crop yield by easing stresses. In the recent decade, due to regular droughts, infrequent precipitation, salinity, and increased temperature, the climate alternation has changed certain ecological systems. As a result of these environmental changes, crop yield has decreased worldwide. The role of biogenic Ag nanomaterials in enhancing methylglyoxal detoxification, antioxidant defense mechanisms, and generating tolerance to stresses-induced ROS injury has been methodically explained in plants over the past ten years. However, certain studies regarding stress tolerance and metal-based nanomaterials have been directed, but the particulars of silver nanomaterials arbitrated stresses tolerance have not been well-reviewed. Henceforth, there is a need to have a good understanding of plant responses during stressful conditions and to practice the combined literature to enhance tolerance for crops by utilization of Ag nanoparticles. This review article illustrates the mechanistic approach that biogenic Ag nanomaterials in plants adopt to alleviate stresses. Moreover, we have appraised the most significant activities by exogenous use of Ag nanomaterials for improving plant tolerance to salt, low and high temperature, and drought stresses.

On virus and nanomaterials – Lessons learned from the innate immune system – ACE activation in the invertebrate model Enchytraeus crypticus

Current human research on COVID-19 – SARS-CoV-2 (Severe Acute Respiratory Syndrome-Corona Virus) showed that ACE2 (Angiotensin Converting Enzyme 2) is a functional receptor to which the spike proteins attach. Invertebrates have been exposed to a wide array of threats for millennia and their immune system has evolved to deal with these efficiently. The annelid Enchytraeus crypticus, a standard ecotoxicological species, is an invertebrate species where extensive mechanisms of response studies are available, covering all levels from gene to population responses. Nanomaterials (NMs) are often perceived as invaders (e.g. virus) and can enter the cell covered by a corona, triggering similar responses. We created a database on E. crypticus ACE gene expression, aiming to analyse the potential knowledge transfer between invertebrates and vertebrates. Total exposure experiments sum 87 stress conditions for 18 different nanomaterials (NMs). ACE expression following TiO2 NM exposure was clearly different from other NMs showing a clear (6–7 fold) ACE down-regulation, not observed for any other NMs. Other NMs, notably Ag NMs, and to some extent Cu NMs, caused ACE up-regulation (up to 4 fold). The extensive knowledge from response to NMs can support the immuno-research community, especially to develop therapies for virus that trigger the innate immune system.

Enhanced Plasmon Based Ag and Au Nanosystems and Their Improved Biomedical Impacts

Numerous specialists and academics have backed the improved physicochemical characteristics of metal substrate (Ag, Au) based composite nanoparticles for a number of applications, including pharmaceuticals, optoelectronics, and environmental impact. Insights of Ag and Au NPs-based nanomaterials will be discussed, as well as important production, physicochemical, and biotechnological characteristics. The plasmon capacities of Ag and Au NPs, along with their customisable form, scale, and surface modification could be described by specified geometries and constituent contents. It was revealed that interaction dynamics of Ag and Au implanted nanomaterials with dopants/defects ratios seem to be more effective in stimulating pathogens by interrupting biochemical reactions. As a result, we focus on defect science in Ag and Au-based nanoscale materials, taking into account surface morphology, ionic packing, and chemical phase assessment. This chapter will cover the important optical, geometrical, and physicochemical features of Ag and Au nanomaterials, and their pharmacological significance.

Pt and Pt–Ag nanoparticles supported on carbon nanotubes (CNT) for oxygen reduction reaction in alkaline medium

In this work, we investigated the effect of the carbon nanotubes (CNT) as alternative support of cathodes for oxygen reduction reaction (ORR) in alkaline medium. The Pt and Pt–Ag nanomaterials supported on CNT were synthesized by sonochemical method. The crystalline structure, morphology, particle size, dispersion, specific surface area, and composition were investigated by XRD, SEM-EDS, TEM, HR-TEM, N2 adsorption-desorption and XPS characterization. The electrochemical activity for ORR was evaluated by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) in alkaline medium. The electrochemical stability was researched by an accelerated degradation test (ADT). Pt/CNT showed the better electrocatalytic activity towards ORR compared with Pt–Ag/CNT and Pt/C. Pt/CNT exhibited higher specific activity (1.12 mA cm−2Pt) than Pt/C (0.25 mA cm−2Pt) which can be attributed to smaller particle size, Pt-CNT interaction, and Pt load (5 wt%). The Pt monometallic samples supported on CNT and Vulcan showed higher electrochemical stability after ADT than Pt–Ag bimetallic. The ORR activity of all materials synthesized proceeded through a four-electron pathway. Furthermore, the EIS results showed that Pt/CNT exhibited the lower resistance to the transfer electron compared with conventional Pt/C and Pt–Ag/CNT.

Synthesis of Ag incorporated ZrO2 nanomaterials for enhanced electrochemical energy storage applications

Ag incorporated ZrO2 nanomaterials was fabricated by the two step hydrothermal approach. An absorbance peak was identified at 311 nm, which was then red shifted to 381 nm due to the addition of Ag nanoparticles. A reduction in the peak intensity was observed in the photoluminescence spectra due to the transition of electrons from ZrO2 to Ag nanomaterials confirming the incorporation of Ag over ZrO2 nanostructures. The elemental composition of the nanomaterials was confirmed by Energy Dispersive X-Ray (EDAX) analysis. X-Ray Diffraction (XRD) patterns established the monoclinic structure of ZrO2 nanomaterials and the average crystallite size was estimated as 23.9 nm. The functional groups present in the molecules of the fabricated nanomaterials were investigated by Fourier Transform Infra Red (FTIR) analysis. Cyclic voltammetry and galvanostatic charging-discharging studies were carried out to analyze the electrochemical behavior of both ZrO2 and ZrO2/Ag nanocomposites. The enhanced highest specific capacitance value was achieved as 676 F/g at the scan rate of 10 mV/s.

Broad-Band-Enhanced Plasmonic Perovskite Solar Cells with Irregular Silver Nanomaterials.

The localized surface plasmon resonance (LSPR) from noble metal nanomaterials (NMs) is a promising solution to approach the theoretical efficiency for photovoltaic devices. However, the plasmon resonance of metal NMs with particular shapes and sizes can only be excited within narrow spectral ranges, which can hardly cover the broad-band solar spectrum. To address this issue, in this article, Ag NMs with irregular shapes and sizes are synthesized and embedded in the electron transport layer of perovskite solar cells. With the outstanding conductivity of Ag NMs, the series resistance and charge transfer resistance of the devices are dramatically decreased. The Ag NMs with larger size could enhance the light-trapping of the devices owing to the far-field light scattering effect. The near-field enhancement by LSPR of Ag NMs with a small size mainly contributes to the promotion of carrier transport and extraction. As a result, broad-band improvements in photovoltaic performance are achieved due to the significant enhancement of light absorption and electrical features. The highest power conversion efficiency of the perovskite solar cells increases from 19.52 to 22.42% after the incorporation of Ag NMs.