Incorporation Of Ag Nanoparticles Research Articles

Light Trapping Effect in Perovskite Solar Cells by the Addition of Ag Nanoparticles, Using Textured Substrates.

In this contribution, the efficiencies of perovskite solar cells have been further enhanced, based on optical optimization studies. The photovoltaic devices with textured perovskite film can be obtained and a power conversion efficiency (PCE) of the textured fluorine-doped tin oxide (FTO)/Ag nanoparticles (NPs) embedded in c-TiO2/m-TiO2/CH3NH3PbI3/Spiro-OMeTAD/Au showed 33.7% enhancement, and a maximum of up to 14.01% was achieved. The efficiency enhancement can be attributed to the light trapping effect caused by the textured FTO and the incorporated Ag NPs, which can enhance scattering to extend the optical pathway in the photoactive layer of the solar cell. Interestingly, aside from enhanced light absorption, the charge transport characteristics of the devices can be improved by optimizing Ag NPs loading levels, which is due to the localized surface plasmon resonance (LSPR) from the incorporated Ag NPs. This light trapping strategy helps to provide an appropriated management for optical optimization of perovskite solar cells.

Enhanced Photoactivity and Hydrogen Generation of LaFeO3 Photocathode by Plasmonic Silver Nanoparticle Incorporation

A plasmonic LaFeO3–Ag (LFO-Ag) photocathode was synthesized by incorporating Ag nanoparticles to excite surface plasmon resonances (SPRs) for enhanced light harvesting to drive photoelectrochemical (PEC) hydrogen evolution. The Ag nanoparticles were modeled using finite difference time domain (FDTD) simulations, and the results show an optimal dimension of 50–80 nm for SPR enhancement. Nanostructured LFO films were prepared by a novel and inexpensive spray pyrolysis method, and the Ag nanoparticles were dispersed uniformly on to the films by simple spin coating method. The LFO-Ag photocathode exhibited strong light absorption capability and high current density, twice that of its untreated counterpart. This subsequently led to enhanced PEC hydrogen evolution, doubling the volume of hydrogen generated compared to untreated LFO. The enhancement is ascribed to the strong SPR effect and the synergy between the Ag nanoparticles and nanostructured LFO photocathode.

High thermal conductivity liquid metal pad for heat dissipation in electronic devices

Novel thermal interface materials using Ag-doped Ga-based liquid metal were proposed for heat dissipation of electronic packaging and precision equipment. On one hand, the viscosity and fluidity of liquid metal was controlled to prevent leakage; on the other hand, the thermal conductivity of the Ga-based liquid metal was increased up to 46 W/mK by incorporating Ag nanoparticles. A series of experiments were performed to evaluate the heat dissipation performance on a CPU of smart-phone. The results demonstrated that the Ag-doped Ga-based liquid metal pad can effectively decrease the CPU temperature and change the heat flow path inside the smart-phone. To understand the heat flow path from CPU to screen through the interface material, heat dissipation mechanism was simulated and discussed.

Influence of the thermal contact resistance on the thermoelectric property of PANI/Ag nanocomposites

In this paper, the experimental electrical conductivity and the thermal conductivity of PANI/Ag nanocomposites are firstly measured, both of which increases with the increase of the Ag nanoparticle content while the percolation phenomenon is only exhibited clearly for the electrical conductivity. The electrical conductivity increase much fast than that of the thermal conductivity, which leads to the ratio between the electrical and thermal conductivities enlarged about 100 times with the increase of the filler content. To reveal the underlying mechanism of the different percolation threshold for the electrical and thermal conductivities, the thermal contact resistance between Ag nanoparticles is calculated with our improved Agari's model. It reveals that: with the increase of the filler content, the thermal contact resistance should be responsible for the different increasing tendencies or percolation threshold of the electrical and thermal conductivities. The measurement of the Seebeck coefficient shows that the incorporation of Ag nanoparticles in the PANI matrix has little effect on the Seebeck coefficient of PANI. The large figure-of-merit enhancement of the PANI/Ag nanocomposites should result from the larger percolation threshold of the thermal conductivity than that of the electrical conductivity due to the thermal contact resistance.

ZnSe/ZnS core-shell quantum dots incorporated with Ag nanoparticles as luminescent down-shifting layers to enhance the efficiency of Si solar cells

Luminescent down-shifting (LDS) is a spectral conversion method for improving the short-wavelength response of Si-based solar cell by transforming shorter wavelength (200 nm-400 nm) into longer wavelength (>400 nm). In this paper, LDS efficiency was enhanced through incorporating Ag nanoparticles into ZnSe/ZnS quantum dots (QDs), as demonstrated by photoluminescence (PL) spectra and finite-difference time-domain (FDTD) simulation results. The mixed Ag/ZnSe/ZnS QDs were spin-coated on the surface of manufactured Si-solar cell so as to efficiently utilize LDS properties. The external quantum efficiency (EQE) and short-circuit current density (Jsc) of Ag/ZnSe/ZnS QDs–Si hybrid solar cell were respectively increased by 30% and 7.5% compared to those of ZnSe/ZnS–Si hybrid solar cell. These improvements were mainly ascribed to localized surface plasmonic (LSP) enhancement effect of Ag nanoparticles. Such small but distinct improvements are expected to provide the theoretical basis and technical support for the development of photovoltaic devices in the future.

Magnetic ordered mesoporous carbon composites incorporating Ag nanoparticles as SERS substrate for enrichment and detection of trace mercaptan compounds

Fe3O4 magnetic nanoparticles and Ag nanoparticles reduced by reductant were incorporated on ordered mesoporous carbon to form magnetic ordered mesoporous carbon composites incorporating Ag nanoparticles (magnetic OMC–Ag). The prepared magnetic OMC–Ag as a surface-enhanced Raman scattering (SERS) substrate not only exhibited a clearly enhanced effect but also showed enrichment ability for the detection of 4-nitrothiphenol. Ag nanoparticles-incorporated magnetic carbon composites as SERS substrate displayed Raman enhancement phenomenon for the detection of 4-nitrothiphenol and showed high stability.

Enhanced Photocatalytic Activity of Diamond Thin Films Using Embedded Ag Nanoparticles.

Silver nanoparticles embedded into the diamond thin films enhance the optical absorption and the photocatalytic activity toward the solvated electron-initiated reduction of N2 to NH3 in water. Here, we demonstrate the formation of diamond films with embedded Ag nanoparticles <100 nm in diameter. Cross-sectional scanning electron microscopy (SEM), energy-dependent SEM, and energy-dispersive X-ray analysis demonstrate the formation of encapsulated nanoparticles. Optical absorption measurements in the visible and ultraviolet region show that the resulting films exhibit plasmonic resonances in the visible and near-ultraviolet region. Measurements of photocatalytic activity using supraband gap (λ < 225 nm) and sub-band gap (λ > 225 nm) excitation show significantly enhanced ability to convert N2 to NH3. Incorporation of Ag nanoparticles induces a nearly 5-fold increase in activity using a sub-band gap excitation with λ > 225 nm. Our results suggest that internal photoemission, in which electrons are excited from Ag into diamond's conduction band, is an important process that extends the wavelength region beyond diamond's band gap. Other factors, including Ag-induced optical scattering and formation of graphitic impurities are also discussed.

Electrically driven plasmon-exciton coupled random lasing in ZnO metal-semiconductor-metal devices

Electrically driven plasmon-exciton coupled random lasing is demonstrated by incorporating Ag nanoparticles on Cu-doped ZnO metal-semiconductor-metal (MSM) devices. Both photoluminescence and electroluminescence studies show that emission efficiencies have been enhanced significantly due to coupling between ZnO excitons and Ag surface plasmons. With the incorporation of Ag nanoparticles on ZnO MSM structures, internal quantum efficiency up to 6 times is demonstrated. Threshold current for lasing is decreased by as much as 30% while the output power is increased up to 350% at an injection current of 40 mA. A numerical simulation study reveals that hole carriers are generated in the ZnO MSM devices from impact ionization processes for subsequent plasmon-exciton coupled lasing.

Enhancement of Kerr Signal in Co Thin Films Incorporating Ag Nanoparticles Surrounded by TiO2

In this study, we demonstrate the effect of localized surface plasmon resonance (LSPR) on magneto-optical (MO) activity of Co thin films incorporating Ag nanoparticles (NPs) so that the Ag NPs were surrounded by TiO2 (Ag [TiO2]). The deposition of Co on glass substrates was performed using an oblique deposition technique, thereby obtaining a variable film thickness. Three samples of glass/Co, glass/Co/Ag NPs, and glass/Co/Ag [TiO2] were compared with each other in terms of Kerr signal intensity. Our results show that while all samples have an easy axis in the film plane, the corresponding Kerr signal is amplified in the glass/Co/Ag [TiO2] structure. A combination of SPR and light localization is the reasoning behind the amplification. These studies may open a new route in the research area of LSPR-based MO Kerr effect since the improved LSPR enhances MO properties.

Efficiency enhancement of fluorescence blue organic light-emitting diodes by incorporating Ag nanoparticles layers due to a localized surface plasmon

Enhanced electroluminescence in blue organic light-emitting diodes (OLEDs) is obtained by incorporating Ag nanoparticles (NPs) into hole injection layer of poly(3,4- ethylenedioxythiophene):polystyrene sulfonic acid (PEDOT:PSS). The absorption peak of the localized surface plasmons (LSPs) introduced by the 60 nm Ag NPs matches the emission wavelength of the blue OLEDs were matched at wavelength of 442 nm. In addition, to maximize their coupling and to prevent the quenching of the emission, the distance between surface plasmons (SPs) around NPs and organic fluorophores is optimized. Finally, the emission intensity and the current efficiency of diode with Ag NPs were increased by 19% and 18%, respectively.

Improved NO2 sensing performance of electrospun WO3 nanofibers with silver doping

This work reports the enhancement of NO2 gas sensing response which owing to the incorporation of Ag nanoparticles into WO3 nanofiber matrices. Ag-doped WO3 nanofibers were fabricated by electrospinning. The Ag dopant levels ranged from 1 to 10 mol%. The microstructures and chemical compositions were examined using a series of material characterization methods including TEM, SEM, XRD, and XPS. Porous mats of nanofibers comprising monoclinic WO3 nanoparticles (28–39nm) incorporated with small Ag particles were observed. The NO2 gas sensing performance was investigated at various gas concentrations (0.5–5ppm) and operating temperatures (200–275°C). For 5ppm NO2 gas detection measured at 225°C, the 3 mol% Ag-doped WO3 nanofiber gas sensor exhibited the highest gas response (Rg/Ra) of 90.3. This was approximately 9 times higher than that of the undoped sample. The response and recovery time were found to be in the range of 6–18min. The response analysis obtained from CH4, NH3, SO2, H2S, and NO2 gas measurements suggests that the sensor has excellent selectivity toward NO2 gas. The improved gas response of Ag-doped WO3 nanofibers was attributed to both electronic and chemical sensitization mechanisms provided by Ag nanoparticles. Significant decreases in gas responses were observed in the samples with higher Ag dopant levels (5 and 10 mol%), where the crystallite size of Ag nanoparticles became too large and hindered their catalytic effects.

Microstructure, electrochemical behaviour and bio-fouling of electrodeposited nickel matrix-silver nanoparticles composite coatings on copper

Bio-fouling is a major cause of accelerated corrosion and premature failure of materials used in industry. This study presents synthesis, characterisation, bio-fouling, and electrochemical corrosion behaviour of Ni matrix-Ag nanoparticles based composite coatings for anti-corrosive and anti-fouling applications in sea water or marine environment. Two Ni-Ag composite coatings of compositions, Ni-0.25at.% Ag and Ni-0.75at.% Ag, were electrodeposited on copper by dispersing controlled amounts of chemically synthesised Ag nanoparticles into Ni++ bath. Effect of Ag nanoparticles on electrochemical corrosion, Ni passivation and bio-fouling of these composite coatings is highlighted. Incorporation of Ag nanoparticles into Ni matrix was found to influence texture, Ni crystallite size, and strain of the Ni-Ag composite coatings. Between pure Ni and two Ni-Ag composite coatings, Ni-0.25at.% Ag coatings exhibited the highest corrosion resistance in 3.5% NaCl owing to a synergetic combination of relatively large, strain-free Ni crystals with a pronounced texture along [111] direction. During anodic polarisation in 3.5% NaCl, Ag nanoparticles embedded into Ni matrix induced galvanic passivation of Ni phase, which improved tendency of the composite coatings for passivation. Upon exposure to sulphate reducing bacteria, these composite coatings showed greater resistance to formation of bio-film, which confirmed their anti-fouling properties. Extent of bio-film decreased with amount of incorporated Ag nanoparticles in these composite coatings. Bio-film led to a reduction in corrosion resistance of the coatings. This reduction in corrosion resistance due to bio-film decreased with increasing Ag content of the coatings. It can be concluded that anti-microbial nanoparticles embedded in a suitable metal matrix can open up new avenues in addressing bio-fouling and microbially induced corrosion in sea water.

Tailoring of optical and electrical properties of PMMA by incorporation of Ag nanoparticles

Silver–poly(methyl methacrylate) (Ag–PMMA) nanocomposite films were prepared via ex situ chemical route by employing sodium borohydride ( $$\hbox {NaBH}_{4}$$ ) as a reducing agent. In this study, PVP-stabilized Ag nanoparticles were prepared and mixed with PMMA solution. Optical and structural characterizations of resulting nanocomposite films were performed using UV–visible spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Characteristic surface plasmon resonance (SPR) peak of Ag nanoparticles was observed at about 3.04 eV (408 nm) in absorption spectra of Ag–PMMA nanocomposite films. TEM micrograph revealed that the spherical Ag nanoparticles with an average diameter of 5.4 $$\,\pm \,$$ 2.5 nm are embedded in PMMA. In Raman spectra, besides shifting of vibrational bands, enhancement in intensity of Raman signal with incorporation of Ag nanoparticles was observed. Current (I)–voltage (V) measurements revealed that conductivity of PMMA increased with increasing concentration of Ag nanoparticles. Analysis of I–V data further disclosed that at voltage 2 V Poole–Frenkel is the dominant conduction mechanism. Urbach’s energy, the measure of disorder, increased from 0.40 eV for PMMA to 1.11 eV for Ag–PMMA nanocomposite films containing 0.039 wt% of Ag nanoparticles.

Effects of surface plasmon resonance of the Ag nanoparticles on the efficiency and color stability of the blue light phosphorescent organic light emitting diodes

The electroluminescence (EL) performance of the blue light phosphorescent organic light emitting diode (OLED) incorporating Ag nanoparticles (Ag NPs) beneath or within the PEDOT:PSS hole injection layer (HIL) has been investigated, and the surface plasmon-enhanced EL efficiency has been demonstrated. The OLED with the structures of Ag NPs beneath and within the HIL exhibit the respective optimal power efficiency of 43 lm/w (EQE of 31%) and 35 lm/w (EQE of 25%) at the brightness of 1000 cd/m2 compared to that of 15 lm/w (EQE of 13%) for the control device without Ag NPs incorporated. The mixing volume ratio of Ag NPs to PEDOT:PSS reveals remarkable influence on the OLEDs EL efficiency, and ratio of 1:3 is proved to be optimal due to the sufficient coupling between the surface plasmon of Ag NPs and excitons in the emission layer without significant exciton quenching from the Ag NPs. The blue OLEDs with Ag NPs beneath HIL also reveal considerable color shifting with the increasing luminance while the OLEDs with the mixture of Ag NPs and PEDOT:PSS at various ratios demonstrate stable EL spectrum. The influence of localized surface plasmon resonance (LSPR) from Ag NPs in the different structures on the EL efficiency and spectrum is discussed in details.

Plasmonic effects of quantum size metal nanoparticles on dye-sensitized solar cell

Gel polymer electrolytes (GPEs) based on poly(ethylene oxide) (PEO) and phthaloyl chitosan (PhCh) for dye-sensitized solar cells (DSSCs) have been synthesized and characterized. The GPEs have been prepared using different weight fractions of PEO and PhCh that have been added to a fixed composition solution of tetrapropylammonium iodide (TPAI), dimethylformamide (DMF) and iodine (I-2) crystals. The ionic conductivity behavior of prepared GPEs was studied using impedance spectroscopy. The sample having 70 wt.% PEO and 30 wt.% PhCh showed the highest ionic conductivity of 7.36 mS cm(-1) at room temperature. The photoanode of the DSSC consists of two TiO2 layers. The first or compact layer has a thickness of similar to 5 mu m and the TiO2 nanoparticles have an average size of 14 nm. The second layer of TiO2 nanoparticles has an average size of 21 nm. In order to adsorb dye molecules, the TiO2 photoanodes were soaked in anthocyanin and ruthenium 535 (N3) dye solutions. The GPE has been deposited between the dye/ TiO2 photoanode and platinum (Pt) counter electrode in a sandwich-like structure. Results showed that the fabricated DSSC with an electrolyte containing 70 wt.% PEO: 30 wt.% PhCh exhibited the highest efficiency for both anthocyanin and N3 dyes and the efficiency and ionic conductivity trend versus PEO content are similar. On addition of different amounts of Ag nanoparticles (0, 10, 20, 30, 40 mu L), with average size of 10 nm to the second TiO2 layer, the performance of DSSCs with anthocyanin sensitizer and N3 dye improved. The cell with anthocyanin/(TiO2 + 10 mu L Ag nanoparticles) showed a 21%, 17.2% and 39.6% increase in short circuit current density (J(sc)), fill factor (FF), and light to electricity conversion efficiency (.) respectively compared to the cell without Ag nanoparticle. The DSSC fabricated with TiO2 photoanode containing 20 mu L Ag nanoparticles soaked in N3 dye exhibits Jsc, FF, and. of 15.24 mA cm(-2), 57% and 5.21% respectively. The incorporation of Ag nanoparticles has resulted in a 17% and 13% increase in Jsc, and., respectively, for N3 based cells. This performance enhancement with the addition of Ag nanoparticles can be attributed to improvement of light scattering and charge transport as a result of plasmonic resonance.

Performance enhancement of polymer solar cells by incorporating Ag nanoparticles at an indium tin oxide/MoO3 buffer layer interface

In the present study, the plasmonic effects of silver nanoparticles (Ag NPs) have been utilized to improve the performance of polymer solar cells. Plasmonic polymer solar cells were fabricated by incorporating Ag NPs at the indium tin oxide (ITO)/MoO3 buffer layer interface. The size of the Ag NPs has been optimized to improve the device performance. The optimized device with 75 nm sized Ag NPs shows 26% enhancement in the power conversion efficiency (PCE) compared with the reference device. The short circuit current density mainly contributes to the efficiency enhancement compared with other device parameters. The diffuse reflectance measurements indicate that there is significant enhancement in the optical absorption of active layers when Ag NPs are incorporated into the devices. The scattering cross section of Ag NPs and electric field intensity distribution around the nanoparticles were modeled by finite-difference-time-domain simulations. The experimental results and theoretical simulations revealed that both far-field scattering and near-field concentration of light contributed significantly to the PCE enhancement of the devices.

Facile synthesis of ZnO–Ag nanocomposite and its photocatalytic activity

The evolution of photoactive hybrid materials (e.g. noble metal-semiconductor) has resulted in heterogeneous photocatalysis. We report a facile route for the synthesis of ZnO–Ag nanocomposites with varying percentage of loading of the noble metal, expecting a great boost in the photocatalytic behavior of ZnO. The as prepared material was thoroughly characterized by UV–Vis, FTIR, TEM, FESEM, XRD, XPS analyses. The photocatalytic activities of the nanocomposites have been assessed from the ability to degrade methylene blue dye in aqueous solution. The results suggest that incorporation of Ag nanoparticles on the surface of ZnO particles can enhance catalytic activity in comparison to pure ZnO particles under visible light by minimizing the recombination of photogenerated electron–hole pairs.

Synthesis of Ag-coated TiNb2O7 composites with excellent electrochemical properties for lithium-ion battery

Ag/TiNb2O7 composites are synthesized by a facile and effective solid state method and following solvothermal process. It is found that Ag nanoparticles are deposited on the surfaces of TiNb2O7 microcrystals. When Ag/TiNb2O7 is used as the anode for lithium-ion battery, its 2nd discharge capacity is 275.3mA·h·g−1 at 1C, larger than that of pure TiNb2O7 (234.2mA·h·g−1); moreover, Ag/TiNb2O7 exhibits better rate capacity performance than TiNb2O7. The electronic conductivity of the Ag/TiNb2O7 electrode is increased for the incorporation of Ag nanoparticles, which can effectively improve the electron transport in the Li+ insertion/extraction process and accordingly enhance the electrochemical performance.

Light absorption enhancement in organic solar cells with silver nanoparticles and silver meso-flowers

ABSTRACTSilver nanoparticles were used to increase the light absorption of an organic photovoltaic (OPV) device without altering its thickness. A blend of poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] and fullerene-C60 was utilized as an electron donor and electron acceptor respectively to fabricate the organic active layer. Direct incorporation of Ag nanoparticles (NPs) at the bottom of the active layer improved light absorption, and Ag meso-flowers (MFs) showed good potential for plasmonic effects. The size of Ag NPs and MFs, controlled morphology, and nanoparticle position in active layers influenced the light absorption enhancement.

The preparation and thermal performance research of spherical Ag-H2O nanofluids & applied in heat pipe

Spherical silver-water (Ag-H2O) nanofluids with good suspension (more than 85days) have been obtained via one-step method in the water phase without any surfactants or additives in the present work. The size-control technique of spherical Ag nanoparticle has been obtained through adjusting the reaction rate and the mechanism of size effect has been studied in detail. It can be found that the faster the reaction rate, the smaller the nucleation density and the smaller the particle size. The thermal conductivity of spherical Ag-H2O nanofluids were higher than H2O even the few Ag nanoparticle incorporation. Based on the preparation of Ag-H2O nanofluids, the effects of particle size, solid content and temperature on the thermal conductivity of spherical Ag-H2O nanofluids were discussed and all the measure was performed in the same condition. The conclusion can be drawn that the thermal conductivity of Ag-H2O nanofluids increases with the content of Ag nanoparticles and temperature increasing and average size of Ag nanoparticles decreasing. The effect mechanism of particle size, temperature and content of Ag nanoparticles has been studied in detail. The Ag-H2O nanofluids were determined to be the Newtonian fluid whose viscosity is close to water and the viscosity increases with the increase of the mass fraction of Ag nanoparticles. The start-up and heat transfer performance of the heat pipe using the spherical Ag-H2O nanofluids have been improved compared to the heat pipe using DI water. It is expected that the spherical Ag-H2O nanofluids with a high thermal conductivity and low viscosity are expected to be new heat transfer fluid.