Ag Doping Research Articles

The impact of Ag dopant on the photocatalytic activity toward methylene blue and antimicrobial activities of g-C3N4/ZnO nanocomposite

The impact of Ag dopant on the photocatalytic activity toward methylene blue and antimicrobial activities of g-C3N4/ZnO nanocomposite

Enhancing the Thermoelectric Performance of n-Type Mg3Sb2-Based Materials via Ag Doping.

The n-type Mg3(Sb, Bi)2 compounds show great potential for wasted heat energy harvesting due to their promising thermoelectric properties. This work discovers that doping transition element Ag into the n-type Mg3(Sb, Bi)2 can effectively optimize the power factor and suppress the lattice thermal conductivity simultaneously. Interestingly, the Ag doping has different effects compared to the isoelectronic and same group element Cu addition studied previously. A high power factor of 19.6µW cm-1 K-2 is obtained at 673K owing to the increased electrical conductivity. At the same time, the lattice thermal conductivity is reduced to ≈0.5W m-1 K-1 because of enhanced phonon scattering induced by Ag atoms. These improvements lead to a peak figure of merit (ZT) of 1.64 at 673K as well as a high average ZT of 1.27 is obtained from 323 K to 673K. Furthermore, a thermoelectric single leg with a competitive conversion efficiency of ≈11% under a hot-side temperature of 673K is fabricated successfully. In addition, a 2-pair module composed of n-type Mg3(Sb, Bi)2 alloy and p-type MgAgSb-based compound demonstrates the high conversion efficiency of ≈7.9% at a temperature difference of 277K, which will significantly upgrade the sustainable energy recycling technology.

Hydrothermal doping of Ag and ZnO nanoparticles in Sterculia cellulose mat for antimicrobial and photocatalytic applications

Hydrothermal doping of Ag and ZnO nanoparticles in Sterculia cellulose mat for antimicrobial and photocatalytic applications

Silver doping effect on the electrochromic performance of the WO3 thin films produced by thermal evaporation in vacuum

Ag doped WO3 thin films are successfully fabricated by thermal evaporation method in vacuum as precursor, and then annealed at 450 °C in nitrogen gases atmosphere. Cyclic voltammetry, repeating chronoamperometry, chronocolumetry and optical transmittance are recorded in 1 M LiClO4/propylene carbonate electrolyte. The color of the WO3 thin films changes from transparent to the blue under the applied potential of -1.8 and +1.9 V. XRD studies show that all the films have a polycrystalline structure of WO3. The molecular formation is also confirmed by Raman and X-Ray photoelectron spectroscopy (XPS). The EDS elemental mappings clearly confirm the homogeneous distribution of Ag, W and O elements into the WO3 network. From the optical studies, indirect band gap energy of the WO3 decreases as Ag doping level increases. The best coloration and bleaching times (2.33 and 1.25 s) are obtained for the Ag(2%):WO3 thin films, compared to the pure WO3 (3.79 and 1.96 s). The produced WO3 films exhibit high reversibility (39.6/69.1%), high coloration efficiency values (26.3/141.2 cm2/C), and good cycling stability. From the EIS measurements, the charge-transfer resistance is Ag(2%):WO3 < the pure WO3 < Ag(5%):WO3 < Ag(8%):WO3, which means that Ag(2%):WO3 has the biggest electrochemically active surface area. Electronic energy levels of the pure WO3 and the Ag:WO3 thin films are also given. From the Mott-Schottky studies, it is determined that the donor concentration of the materials is of the order of 1014-1015 cm−3. In the literature, there are very limited studies related to electrochromic thin films by thermal evaporation in vacuum. In this sense, the reported results in this study are promising for the electrochromic applications.

Crystallization and Optical Behaviour of Nanocomposite Sol-Gel TiO2:Ag Films.

Sol-gel spin coating method was employed for depositing TiO2 and Ag-doped TiO2 films. The effects of Ag doping and the annealing temperatures (300-600 °C) were studied with respect to their structural, morphological, vibrational, and optical properties. Field Emission Scanning Electron microscopy (FESEM) investigation exhibited the grained, compact structures of TiO2-based films. Ag incorporation resulted in a rougher film surface. X-ray diffraction (XRD) results confirmed the formation of Ag nanoparticles and AgO phase, along with anatase and rutile TiO2, strongly depending on Ag concentration and technological conditions. AgO fraction diminished after high temperature annealing above 500 °C. The vibrational properties were characterized by Fourier Transform Infrared (FTIR) spectroscopy. It was found that silver presence induced changes in IR bands of TiO2 films. UV-VIS spectroscopy revealed that the embedment of Ag NPs in titania matrix resulted in higher absorbance across the visible spectral range due to local surface plasmon resonance (LSPR). Ag doping reduced the optical band gap of sol-gel TiO2 films. The optical and plasmonic modifications of TiO2:Ag thin films by the number of layers and different technological conditions (thermal and UV treatment) are discussed.

Modulation of Phase-Locking Characteristics of NbOx Memristor by Ag Doping.

Memristors based on niobium oxide have attracted wide interest due to their applications in artificial neural network. Phase-locking (PL) characteristics of NbOx newly explored roots in complex nonlinear dynamics and exhibits great potential in periodical signal handling because of its bioinspired nature. In this study, we fabricate a Pd/Nb/Ag-NbOx/Nb/Pd memristive structure and study the effects of Ag doping on the PL characteristics. We clearly see that the NbOx memristor responds to signal in three distinct patterns. For the low-frequency input, the memristor fires spike series and locks the phase near during the positive period of sinusoidal input, and it encodes the input features by the spike number per period. For the middle-frequency input, the memristor fires one spike per period at a definite phase. The output has the same frequency as the input. The locked phase is proportional to the input frequency. For the high-frequency input, the memristor transforms high frequency to low frequency signal and locks at a definite phase higher than 2π. We combined the microstructural analysis and chaos dynamics to know that Ag doping will lower the activation energy, enhance the responding rate, and enhance thermal conductivity, which extends the locked frequency to 1.7 times the value of the undoped NbOx memristor. We also obtained the locked frequency of even 40 MHz after modulating the elementary circuit configuration according to the material modification and chaos model. Our study proposes to handle a signal with high efficiency resembling auditory sense and inspires a novel artificial intelligent computation prototype.

A study on the influence of metal Ag, Cu, and Fe doping on the morphological, structural, and photocatalytic activity of TiO2 nanostructures

Metal-doped TiO2 nanoparticles (NPs) were elaborated by a sol–gel method using n-butoxide of titanium (IV) as precursors. The resulting NPs were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Raman spectroscopy, and FTIR analysis. The SEM study shows the formation of a spheres-like structure. The EDX analysis proves the presence of Ag, Fe, and Cu on the doped TiO2 NPs. XRD and Raman spectroscopy analysis show that the doping inhibited the phase transformation and stabilized the anatase phase. The photocatalytic activity of prepared TiO2 NPs was evaluated in methylene blue (MB) photodegradation under UV irradiation. The results reveal that the doped TiO2 NPs were more efficient than undoped TiO2 NPs in the degradation of MB. The Cu-doped TiO2 NPs were found to be more efficient in this reaction with a degradation efficiency of about 92.31 % and a kinetic rate constant of about 10−2 min−1. The studies of the reactive species show that the holes are the main reactive species responsible for the photocatalytic oxidation of MB. Furthermore, the reusability studies showed that the photocatalysts are globally stable for the photodegradation of MB.

Significantly Enhanced Thermoelectric Performance of p-Type Mg3Sb2 via Zn Substitution on Mg(2) Site: Optimization of Hole Concentration Through Ag Doping.

n-Type Mg3Sb2-based thermoelectric materials have recently garnered significant interest due to their superior thermoelectric efficiency. Yet, the advancement of p-type Mg3Sb2 for thermoelectric applications is impeded by its lower dimensionless figure of merit (zT). In this study, we demonstrate the improved thermoelectric performance of p-type Mg3Sb2 through the strategic optimization of Zn content and Ag doping on the Mg/Zn(2) site. Initially, samples of Mg3-xZnxSb2 (x = 0, 0.5, 1.0, and 1.5) were synthesized via elemental reactions within a Pyrex tube, followed by densification through hot pressing. X-ray diffraction analysis confirmed that the Mg3-xZnxSb2 phases retain the same Pm1 space group as the pristine Mg3Sb2 phase. The strategic substitution of Zn improved the power factor via band convergence and reduced lattice thermal conductivity by introducing point defect phonon scattering. This led to a peak zT of 0.5 at 725 K, with an average zT of 0.25 across the 325-725 K range. Enhancement in carrier concentration was achieved by doping Ag onto the Zn site, culminating in a peak zT of 0.95 at 725 K and an average zT of 0.46 between 325 and 725 K for the Mg2Zn0.97Ag0.03Sb2 sample. This performance surpasses that of most p-type Mg3Sb2-based materials, markedly advancing the potential for Mg3Sb2-based materials in midtemperature heat recovery thermoelectric generators.

11.88% Efficient Flexible Ag-Free CZTSSe Solar Cell: Spontaneously Tailoring the Alkali Metal Level.

Alkali metal is the requirement for highly efficient Cu2ZnSn(S, Se)4 (CZTSSe) solar cells, thus it is crucial to additionally incorporate alkali metal into the absorber layer for flexible solar cells. However, the efficiency of flexible CZTSSe devices reported to date, based on the conventional alkali incorporation strategies, still lags behind those made on rigid substrates. One of the main issues is the inability to control the alkali content and distribution in the absorber layer. Here, a facile alkaline incorporation approach is proposed, effectively regulating the content and distribution of alkali metals in the film. Such a method can spontaneously tailor the alkali metal content to a proper level, thus leading to the suppression of non-radiative recombination and a better carrier transport through the enhanced film quality and the optimized band binding structure. Finally, a champion flexible CZTSSe solar cell with an efficiency of 11.88% is achieved, the highest reported efficiency for a CZTSSe solar cell without noble Ag doping. This study affords an innovative spontaneous alkali-doping design for the preparation of high-performance flexible CZTSSe solar cells and provides a deeper insight into the extent of alkali metal doping.

Assessment of silver and graphitic carbon nitride doped cadmium selenide quantum dots as an efficient dye degrader and antibacterial agent: In silico molecular docking analysis

This study demonstrates the synthesis of co-precipitated cadmium selenide (CdSe) quantum dots (QDs) doped with (2 and 4 wt %) of silver (Ag) and fixed quantity of graphitic carbon nitride (g-C3N4) for catalytic as well as antibacterial potential with molecular docking (MD) analysis. Comprehensive characterizations investigated the structural composition, surface morphology, elemental composition, and optical properties. XRD revealed the multiple phases (hexagonal and cubic) of CdSe with a notable rise in the diffraction peaks intensity upon doping. The optical studies demonstrated the range of absorption peaks, which increased upon doping confirmed through band gap energies significantly altered. TEM study revealed that a sheet of g-C3N4 overlapped with CdSe QDs, and certain nanorod-like structures emerged after Ag doping. HR-TEM was employed for the d-spacing computation of prepared samples and exposed a decreasing trend as the Ag concentration increased. Furthermore, the catalytic activity (CA) performed against RhB dye showed maximum results in the acidic medium with a higher concentration of Ag into g-C3N4 doped CdSe. The efficient bactericidal efficacy was evaluated against S. aureus bacteria with the highest inhibition zone of 13.75 mm for 4% Ag doping, which was further explained by investigating their inhibitory effects on DNA gyrase and tyrosyl-tRNA synthetase via MD.

Boosting photoelectrochemical water splitting performance via nanostructured Ag-CuO thin films

Undoped and doped copper oxide (CuO) with silver (Ag) was prepared using the SILAR technique on the ITO substrate to generate green hydrogen from the water-splitting process. The (−111) and (111) were the most intense reflections of crystallographic planes observed in pure and Ag-doped CuO thin films. Ag doping within the crystal structure of pristine leads to increasing the crystallite size. FESEM images show homogeneity and uniform distribution for the pure and Ag-doped CuO thin films that confirm the particles have small sizes, give more features and are responsible for the target application. The doping process affected the energy band gap where it was 2.2 eV for the pure sample then descended to 1.9 eV as doping reached 5 % concentration of Ag element. The photoelectrochemical testing showed that the Ag 5 % content photoelectrode has a high value of photocurrent density approximately ∼ - 5 mA/cm2.

Effect of trace silver addition on microstructure and properties of Cu-0.45Cr-0.1Zr alloy

Cu-0.45Cr-0.1Zr-(0.3Ag) were produced and subjected to multistage thermo-mechanical treatment. The microstructure evolution and properties of the alloys during aging were investigated in detail and the effect of trace Ag on comprehensive properties of Cu-Cr-Zr alloy was discussed by kinetic and strength calculations. The results showed that Cu-0.45Cr-0.1Zr-0.3Ag alloy had a higher strength than Cu-0.45Cr-0.1Zr alloy while maintaining a high electrical conductivity. After multistage thermo-mechanical treatment, the tensile strength, yield strength and electrical conductivity of Cu-0.45Cr-0.1Zr-0.3Ag alloy reached 611MPa, 601MPa and 78.7 %IACS, respectively. The addition of Ag had little influence on the precipitation process of Cu-Cr-Zr alloy during aging: Cr particles transitioned from GP zones to face-centered cubic (fcc) structure and finally stabilized in body-centered cubic (bcc) structure, however, the composition of Zr precipitates changed after Ag doping. Most of Zr atoms segregated at grain boundaries in the form of Cu4AgZr in Cu-0.45Cr-0.1Zr-0.3Ag alloy instead of Cu5Zr in Cu-0.45Cr-0.1Zr alloy. The calculation results showed that the addition of Ag refined the size of Cr particle, increased the density of dislocations, enhanced the effect of dislocation strengthening.

Effect of Ag doping on the structural, morphological, optical and antibacterial activity of ZnS nanoparticles

In this study Ag-doped ZnS nanostructures for antibacterial activity were prepared by means of a facile wet-chemical method. XRD study reveals a decrease in the intensity of XRD peaks and the presence of an additional peak for silver which further affirms the incorporation of silver ions in ZnS matrix. The synthesized 1% Ag-doped ZnS nanostructures have the average particle size distribution of 16.45 ± 0.13 nm based on the TEM image. The antimicrobial activity of pure ZnS and Ag-doped ZnS were evaluated against Staphylococcus aureus and Escherichia coli. The results show that the bacterial inhibition was enhanced due to the doping of Ag into ZnS matrix in contrast to ZnS. This results obtained from the antibacterial study could be capitalized to be administered as a potent antibacterial drug for biomedical application.

Synthesis and characterization of the doped/co‐doped SnO2 nanoparticles by the sol–gel method

AbstractTin oxide (SnO2) is one of the important semiconductors used in the application of solar cells because of its chemical–mechanical stability and wide band gap. These properties are very important for the performance development and photoanode optimization of a dye‐sensitized solar cell (DSSC). However, the low conduction band value of SnO2 reduces the photovoltaic efficiency, which limits the application of DSSC. Therefore, the doping strategy was used to increase the sensitivity to the visible light spectrum and change the light absorption properties of SnO2. In this paper, pure SnO2, Ag/SnO2, Pt/SnO2, and Pt/Ag/SnO2 nanoparticles were synthesized at the nanoscale by a simple chemical sol–gel method. To characterize the structure, morphological/chemical properties, optical properties, and surface properties of the synthesized SnO2 nanoparticles, X‐Ray Diffraction (XRD), ultraviolet–visible, Brunauer–Emmett–Teller, Scanning Electron Microscopy (SEM)/Energy Dispersive X‐Ray Spectroscopy (EDX), Transmission Electron Microscopy (TEM), and particle size analysis were respectively used. XRD results showed that the crystal sizes varied between 8.8 and 12.2 nm depending on the doping. Doping processes resulted in reductions in particle sizes. Optical studies resulted in decreases in the band gap with the doping process. The conclusions obtained have shown that Ag doping, and Pt–Ag co‐doping can be promising for use as photoanode materials in semiconductor technology and especially in DSSC applications.

Rational composition engineering toward high thermoelectric performance in p-type EuMg2Sb2-based materials

Mg-based compounds are emerging materials for efficient thermoelectric conversion, as exemplified by n-type Mg3Sb2-based materials, while a high performing p-type Mg3Sb2 material is lacking. EuMg2Sb2, a derivative of Mg3Sb2, has revealed potential as a high-performance alternative to p-type Mg3Sb2-based materials, while pristine EuMg2Sb2 suffers from low carrier concentration. Herein, we reveal that both Zn substitution for Mg and Yb substitution for Eu not only boost the carrier concentration and mobility of p-type EuMg2Sb2-based materials, but also sharply diminish the lattice thermal conductivity via enhancing phonon scattering. Band structure calculation shows that Zn substitution minimizes the energy difference between different bands at the valence band maximum and reduces the band effective mass, leading to optimized band structure. Combined with the role of Ag doping in increasing the carrier concentration and power factor, p-type Eu0.5Yb0.5Mg1.0975Zn0.9975Ag0.005Sb2 sample obtains a maximal dimensionless figure of merit (zT) value of 1.18 at 823 K, which compares favorably to those of EuMg2Sb2 and other p-type Mg–Sb-based Zintl materials. This study demonstrates the efficacy and importance of delicate composition engineering in boosting the thermoelectric performance of p-type EuMg2Sb2.

Ultrasound-responsive ZnS:Ag QDs loaded TiO2 biointerfaces: In situ sonodynamic antimicrobial therapy for biomedical implants

Sonodynamic therapy (SDT) is extensively utilized for its profound tissue penetration capabilities in treating deep-seated infections, yet achieving precise ultrasonic treatment at the implant surface remains challenging. Herein, details the development of a novel infection microenvironment-sensitive nano-interface (TN-HHTZ), aimed at enhancing SDT efficacy for treating implant-related infections. The ZnS:Ag quantum dots (ZnS:Ag QDs) are functionalized using tyramine-modified hyaluronic acid (HA-Tyr) and horseradish peroxidase (HRP), resulting in the formation of a hydrogen peroxide (H2O2)-sensitive composite sonosensitizer (HHTZ). HHTZ is loaded onto a titanium dioxide nanotube (TN) array to form TN-HHTZ. Upon infection, ultrasonic triggering causes the rapid release of HHTZ, which interacts with H2O2 in the infected area to form a gel, thereby enabling prolonged enrichment of ZnS:Ag QDs at the site of implant infection. The doping of Ag in ZnS:Ag QDs enhances energy conversion, enabling TN-HHTZ to generate a significant amount of reactive oxygen species (ROS) during the SDT process, thereby boosting its antimicrobial efficacy and ensuring sustained antimicrobial activity throughout the infection period. The TN-HHTZ hydrogel on the implant surface promotes bone cell proliferation and recovery, providing an innovative and holistic strategy for treating and recovering from implant-associated microbial infections.

Influence of Ag doping on structural, morphological, and optical characteristics of sol-gel spin-coated TiO2 thin films

Pure and Ag-doped Titanium dioxide (TiO2) thin films have been synthesized via the sol-gel spin coating method, and their structural, morphological, and optical properties have been investigated. X-ray diffraction analysis verifies that the polycrystalline anatase TiO2 phase is retained up to 2 % Ag doping. However, lattice expansion and grain refinement down to 25.345 nm are observed with increasing Ag content. Scanning electron microscopy (SEM) reveals the formation of large, isolated TiO2 aggregates separated by drying-induced cracks across the film surface. Optical studies show the undoped TiO2 films demonstrate excellent visible transparency (>75 % transmittance) that slightly decreases upon Ag doping, though it remains suitably high for device applications. Meanwhile, optical absorption and defect states improve with more Ag incorporation, narrowing the TiO2 bandgap from 3.83 eV (undoped) to 3.51 eV (2 % Ag-doping) due to the incorporation of Ag-induced electronic states just below the conduction band minimum. The capability to control optical and structural properties through Ag doping highlights the potential of these TiO2 films suitably tailored for photovoltaic devices or self-cleaning coatings.

In vitro cytotoxic study of synthesized Ag and Ce dual-doped α-Fe2O3 nanoparticles on NIH/3T3 and U87 cell lines

The significant potential of iron oxide nanoparticles in biomedical fields, particularly in the delivery of anticancer drugs and in sono-chemodynamic therapy, can be attributed to their remarkable physicochemical properties. Consequently, this study aimed to organize artificially produced hematite nanospheres (α-Fe2O3 NS) that were doped with silver (Ag) and cerium (Ce) using an environmentally sustainable method utilizing taranjabin. Following this, an assessment of their cytotoxicity was conducted. The structure and morphology characteristics of nanoparticles were analyzed using powder X-ray diffraction (PXRD), Field Emission Scanning Electron Microscope (FESEM), energy dispersive X-ray(EDX), and Raman techniques. The FESEM images revealed that the α-Fe2O3 NS exhibited a spherical shape; however, the morphology of the α-Fe2O3 NS doped with Ag and Ce transitioned to a conical form. The doping of Ag and Ce within the α-Fe2O3 structure was thoroughly validated through EDX and Raman analysis. Based on the cytotoxic outcomes, the impacts of Ag and Ce-doped α-Fe2O3 against human glioblastoma(U87) and mouse embryonic fibroblast (NIH/3T3) cells were studied using MTT assay. The results indicated that doped nanoparticles exhibited greater cytotoxic than α-Fe2O3 in both NIH/3T3 and U87 cells. The IC50 values were determined to be 188.33 μg ml−1 for Ag-doped α-Fe2O3 and 308.58 μg ml−1 for Ce-doped α-Fe2O3 against U87 and NIH/3T3 cells, respectively, both of which were lower than the IC50 of α-Fe2O3. Consequently, the doping process significantly enhanced the cytotoxic effect of α-Fe2O3 NS. This study represents the first documentation of the synthesis and anticancer activity of Ag and Ce-doped α-Fe2O3 on NIH/3T3 and U87 cells. However, further investigation into the antitumor efficacy of Ag and Ce-doped α-Fe2O3 in appropriate in vivo models is recommended.

Influence of Ag Doping on Wide-Emperature Tribological Properties of γ-Fe2O3@SiO2 Nanocomposite Coatings on Steel

γ-Fe2O3@SiO2-Ag nanocomposite coatings were prepared to investigate the lubrication performances of the nanocomposite coatings under a wide range of temperatures. The effect of Ag doping on the tribological properties of γ-Fe2O3@SiO2-Ag nanocomposite coatings was studied from room temperature to 600 °C, and the synergistic effect of Ag and oxides in the nanocomposite coatings was investigated. The coefficient of friction and the wear rate of γ-Fe2O3@SiO2-Ag nanocomposite coatings decrease with an increase in Ag content. The tribological properties of 24 wt.%Ag of the nanocomposite coatings are excellent. The stable coefficient of friction is 0.25 at 100 °C and the coefficient of friction is reduced to 0.05 at 500 °C. It was found that the synergistic effect of γ-Fe2O3 and Ag is helpful in improving the tribological properties of γ-Fe2O3@SiO2-Ag nanocomposite coatings over a wide temperature range. Ag plays a lubricating role at low and medium temperatures and oxides play a role in lubrication at high temperatures.

Boosting hydrogen production via alkaline water splitting: Impact of Ag doping in Gd2O3 nanosheet arrays

Hydrogen is a preferable renewable energy carrier in decarbonization efforts to develop sustainable and carbon-free economies due to its high energy density and absence of pollutant emissions during combustion. Among others, electrochemical water splitting (EWS) is a sustainable and eco-friendly technology for producing green hydrogen, representing an essential initial step towards achieving carbon neutrality. In this study, we synthesized a bifunctional electrocatalyst by vertically anchoring Ag-doped Gd2O3 nanosheet arrays onto a three-dimensional nickel foam (NF) substrate. The developed materials were thoroughly investigated using various analytical techniques. Furthermore, the electrocatalyst effectively performed oxygen evolution reactions (OER) and hydrogen evolution reactions (HER). The Ag4%-Gd2O3/NF exhibited boosted HER activity, achieving higher current densities ranging from 10 to 400 mA cm−2 at an overpotential between 14 and 122 mV. This study also highlights the considerable impact of metal sites in both Ag4%-Gd2O3/NF and Gd2O3/NF on the HER catalytic process. Similarly, the Ag4%-Gd2O3 electrocatalyst exhibited superior OER activity, with an overpotential of 209 mV at 10 mA cm−2. The optimized composition also shows Tafel slope of 25 and 20 mVdec−1. Furthermore, Ag4%-Gd2O3 demonstrated the ability to generate oxygen gas bubbles in approximately 20 h for OER, making it an attractive material for energy conversion and storage devices.