Successive Ionic Layer Adsorption And Reaction Research Articles

Optimizing Na2EDTA Concentration for Enhanced Properties of SILAR - Deposited CTS Thin Films

Abstract This study investigates the impact of varying Na2EDTA concentrations on the properties of copper tin sulfide (CTS) thin films deposited on soda lime glass substrates using the successive ionic layer adsorption and reaction (SILAR) method. The aim is to optimize CTS thin film growth for photovoltaic technology applications. CTS thin films were prepared using SILAR with Na2EDTA concentrations of 0.01M, 0.04M, and 0.07M, resulting in samples CTS01, CTS04, and CTS07. Characterization techniques included XRD, SEM, EDAX, FTIR, I-V curves, transmittance spectra, and Tauc plots. The results reveal significant variations in film properties with changing Na2EDTA concentration. XRD patterns indicate polycrystalline films with an orthorhombic CTS phase. SEM images show smooth, dense films with localized clusters. FTIR spectra detect hydrocarbon chains, aromatic rings, and hydroxyl or ether groups. The I-V curves of three samples (CTS01, CTS04, and CTS07) show a voltage-dependent transition from semiconducting to ohmic behavior. The CTS01 exhibits superior conductivity (3.13x10-5/Ωm), while the samples' resistance and conductivity values show an inverse relationship. Transmittance curves display low UV transmittance and high visible transmittance,suggests that the samples are highly absorptive in the UV range and become more transparent in the visible range, indicating potential applications in optical filtering and photovoltaic devices. Tauc plots estimate band gap energies of 3.66, 3.89, and 3.23 eV, indicating high band gap energies suitable for buffer layers in solar cells. The correlation between band gap energy and crystallite size as a function of Na2EDTA concentration is also observed. The study demonstrates the importance of optimizing Na2EDTA concentration for achieving high-quality CTS thin films with desirable properties for photovoltaic applications. The findings highlight the potential of CTS thin films for solar cells, optical filtering, and photonic devices.

Enhancing energy storage with binder-free nickel oxide cathodes in flexible hybrid asymmetric solid-state supercapacitors

The need for flexible electrode materials for the development of flexible supercapacitors has drawn scientific interest recently. We present the successful synthesis of nickel oxide thin films using the successive ionic layer adsorption and reaction (SILAR) method, with the use of three different cationic precursors. This paper provides comprehensive details on the synthesized nickel oxide structure, morphology, and elemental analysis in addition to its electrochemical characteristics, which include specific capacitance (SCs), charge transfer resistance, etc. The produced nickel oxide electrodes achieved specific capacity as 120 C g−1, 517 C g−1, and 1147 C g−1 with different nickel precursors such as nickel chloride, nickel nitrate, and nickel sulfate respectively, at a 1 mA cm−2 current density. A flexible hybrid asymmetric solid-state supercapacitor (FHASS) (S:NiO//PVA-KOH//CuS) device delivered SCs of 165 Fg−1 at a 0.5 mA cm−2 current density, with a maximum SE of 58.87 Wh kg−1 at SP 347 W kg−1. FHASS device exhibits capacitive retention and coulombic efficiency of between 79 % and 96 % after 5000 successful GCD cycles. Also, the device retained an outstanding 97 % of its capacitance at a 175º bending angle. Furthermore, to illustrate its real-world applicability, the constructed device underwent 30 s of charging to a lightning LED table lamp for 90 s. The fabricated device is bringing a new era of broad integration of device-grade applications.

The Impact of Thermal Treatment on the Structural, Optical and Electrochemical Characteristics of Tin Sulfide Films

The development of eco-friendly, cost-effective, and naturally abundant electrode materials for supercapacitors is gaining critical importance in current energy storage research. This study focuses on the synthesis of tin sulfide (SnSx) films via the eco-friendly successive ionic layer adsorption and reaction (SILAR) method, employing varying quantities of L-ascorbic acid (0.8 and 1.0 g) as a reducing agent. Tin sulfide films were deposited on fluorine-doped tin oxide (FTO) glass substrates and subsequently annealed in an inert atmosphere at temperatures ranging from 200 to 400 °C, resulting in thin films of varying thicknesses (100–420 nm). The structural and compositional characteristics of the films were thoroughly analyzed using Raman spectroscopy to confirm the purity and spectroscopic signatures of the sulfides. Further characterization was performed to assess the films’ morphology (scanning electron microscopy, SEM), phase composition (X-ray diffraction, XRD), surface chemical states (X-ray photoelectron spectroscopy, XPS), optical properties (UV–Vis spectroscopy), and electrical properties (Hall measurements). The gathered data were then used to evaluate the potential of tin sulfide films as electrode materials in supercapacitors, highlighting their suitability for sustainable energy storage applications.

Record high photocurrent density of In:Ag2S/ZnO heterojunction enabled by controllable doping for efficient solar hydrogen production

The high mobility of silver ions (Ag+) in silver sulfide (Ag2S) promotes vacancy formation, which serves as the recombination center of the photoexcited charge carriers to severely limit the photoelectrochemical activity of Ag2S. To address this issue, trivalent indium (In3+) is particularly introduced into Ag2S via low–temperature successive ionic layer adsorption and reaction (SILAR) technique, by which are the migration and the side reactions of Ag+ to form the phase impurities largely suppressed. Herein, In3+ is preferentially chosen due to its two more valence electrons with respect to that of Ag+, effectively increasing the carrier concentration of In:Ag2S to not only improve its electrical conductivity but also uplift its Fermi level. The photoexcited electron transport is thereby accelerated to more efficiently separate from the geminate holes, which is further reinforced by depositing In:Ag2S on the zinc oxide nanorods (ZnO NRs) with a relatively low–lying Fermi level. The photogenerated holes are rectified by the built–in electric field at the In:Ag2S/ZnO heterojunction to flow in an opposite direction to that of the electrons, between which the recombination is thereby suppressed. Meanwhile, the light harvesting ability of In:Ag2S/ZnO NRs is also enhanced due to its reduced band gap by In3+. Their synergistic effect renders In:Ag2S/ZnO NRs developed in the present contribution to deliver a record–high photocurrent density of 7.7 mA cm−2 under one–sun illumination, which far exceeds those of not only the undoped counterpart but also additional Ag2S–based photoelectrodes reported in the literature.

Structural, Morphological, and Optical Properties of TiO2/CdS Core-Shell System Prepared by Two Method for Photoelectrocatalytic Application

Abstract The present study utilized the hydrothermal technique to carry out the deposition of films of TiO2. The deposition of CdS on the TiO2 films was accomplished using the chemical bath deposition (CBD) and successive ionic layer adsorption and reaction (SILAR) methods. The morphological and structural characteristics of the TiO2/CdS thin films were investigated using a combination of XRD, SEM, EDX, and AFM techniques. Additionally, the optical properties of the nanostructures were examined using UV-Visible and PL spectroscopic techniques. The X-Ray Diffraction pattern of all TiO2 films revealed the formation of the anatase phase. The CdS present in the Ti/TiO2/CdS samples exhibited a hexagonal structure. The hydrothermal technique employed in the preparation of the TiO2 thin films resulted in the formation of nanofiber morphology, which was evident from the SEM images. The absorption edge data for the TiO2/CdS films demonstrated a shift towards the visible region, indicating a decrease in the bandgap as compared to the TiO2 nanostructure. Significantly improved photoelectrocatalytic performance was observed in the Ti/TiO2/CdS samples prepared using the CBD method, surpassing that of the Ti/TiO2/CdS samples prepared using the SILAR method.

SILAR deposited cadmium sulphide (CdS) over graphitic carbon nitride (g-C3N4) based photo-enhanced triboelectric nanogenerator for self-powered visible light photodetector

Self-powered visible-light photodetectors have gained prominence as sustainable solutions across multiple domains, including optical communication systems, biomedical imaging, and optical interconnections. In this study, we presented a self-powered visible-light photodetector in the form of a triboelectric nanogenerator (TENG), which comprises of g-C3N4/CdS over the indium tin oxide coated poly(ethylene terephthalate) (ITO/PET) sheet and aluminum. Firstly, the as-synthesized g-C3N4 was coated over ITO/PET and thereafter the CdS layer was deposited over g-C3N4 layer by using Successive Ionic Layer Adsorption and Reaction (SILAR) method. The formation of CdS thin layer has been confirmed through various characterization techniques, including SEM (Scanning Electron Microscopy), XRD (X-ray Diffraction), and Raman spectroscopy. The as-fabricated TENG exhibits 29.6 V of open circuit voltage (Voc) and 0.55 µA short circuit current (Isc), when subjected to force through finger tapping. Furthermore, the TENG demonstrates a calculated power density of 2.16 µW/cm2 with an external load of 45 MΩ. The TENG’s output performance achieved a significant improvement, reaching 55 V Voc, when exposed to visible light. This enhancement is credited to the mutual coupling effect and enhanced interfacial interactions, fostering a charge-trapping mechanism. The exceptional efficiency of our fabricated TENG establishes itself as a highly productive hybrid system for developing self-powered system, particularly serving as a self-powered visible-light photodetector.

Enhanced charge carrier separation and stable photoelectrochemical water splitting via a high-performance BiVO4/BiOBr Type-II heterojunction

The development of an ideal photoanode that exhibits broad light absorption, efficient photogenerated carrier separation, and superior transmission efficiency remains a pivotal challenge in enhancing the sluggish photoelectrochemical (PEC) water splitting reaction. Here, we present an efficacious strategy to bolster the PEC performance of oxygen evolution by fabricating a BiVO4/BiOBr heterojunction through a combined electrochemical deposition-calcination approach and the successive ionic layer adsorption and reaction (SILAR) method. The band structure of BiOBr is optimally aligned with BiVO4, enabling the heterojunction to significantly enhance the separation efficiency of photogenerated charges and accelerate the kinetics of PEC water oxidation. Under simulated sunlight irradiation, the BiVO4/BiOBr heterojunction exhibits a remarkable photocurrent density of 2.69 mA/cm2 at 1.23 V vs. reversible hydrogen electrode (RHE), surpassing the performance of bare BiVO4 film (0.46 mA/cm2 at 1.23 V vs. RHE) and demonstrating exceptional stability. This work offers novel insights into the rational design and fabrication of solar-driven PEC water splitting photoanodes.

Impact of different rinsing temperatures on SnS thin films created using the SILAR technique

The (SnS) thin films were prepared by Successive Ionic Layer Adsorption and Reaction (SILAR), a versatile and simple method. The cationic and anionic solutions SnCl2.2H2O and Na2S.9H2O respectively were used as precursor materials, which will be deposited on glass substrates to study the effect of rinsing temperature on the properties of our thin films. The structural, morphological, and optical properties were investigated by using X-ray diffraction, Energy Dispersive X-ray analysis (EDX), Scanning Electron Microscopy (SEM) and spectrophotometer. X-ray Diffraction (XRD) patterns indicated that the deposited SnS thin films have an orthorhombic crystal structure. Uniform deposition of the material over the entire glass substrate was shown by Scanning Electron Microscopy (SEM). The optical band gap energy ranged from 1.5 to 1.82eV for direct transitions and from 0.6 to 0.95eV for indirect transitions.

Photodetector Devices: Investigation of ZnO Thin Films Fabricated via SILAR Technique on Various Substrates:

The synthesis of photodetectors for ZnO nanostructure films on various substrates, including p-type (100) silicon (Si), and porous silicon (pSi), has been achieved through the utilization of a straightforward technique known as the successive ionic layer adsorption and reaction (SILAR) method. To analyze the optical properties, surface morphology, and crystal structure of the ZnO layers, UV-Vis spectrometers, field emission scanning electron microscopes (FESEM), and X-ray diffraction (XRD) were employed. The characterization of the ZnO samples revealed that the number of SILAR cycles has a significant impact on the morphology and optical band gap of the synthesized layer. The Fourier-transform infrared (FTIR) spectrum successfully detected the distinctive extended vibration mode of ZnO. By conducting 20 cycles, high-quality hexagonal ZnO was obtained. The responsivity of the planar ZnO on silicon (ZnO/Si) and ZnO on the porous silicon (ZnO/pSi) surface exhibited variations depending on the substrate surface and bias voltage. The results indicated that the (ZnO/pSi) heterojunction demonstrated a high response in the visible range (350–850 nm) at a low bias voltage. On the other hand, the (ZnO/Si) photodetector displayed a high sensitivity of 666.66% at a low voltage of 1V in comparison to the (ZnO/pSi) photodetector, which exhibited a sensitivity of 483%.

Sequential growth controlled copper vanadate nanopebbles embedded thin films: Electrode to asymmetric supercapacitive device assembly

Supercapacitor performance critically relies on the design of electrodes with both superior electrochemical and mechanical properties. In this study, we present a cost-effective and scalable approach for the synthesis of copper vanadate (Cu3V2O8) nanopebbles integrated into a thin film, tailored for supercapacitor applications. The synthesis was accomplished using the successive ionic layer adsorption and reaction (SILAR) method, which enabled precise control over the deposition of Cu3V2O8 on a stainless steel (SS) substrate. Detailed structural, morphological, and elemental characterizations confirm the successful formation and reveal critical insights into the chemical bonding and oxidation state at material. The supercapacitive performance of Cu3V2O8 electrode has been evaluated in an aqueous NaClO4 electrolyte to assess pseudocapacitive behavior. The Cu3V2O8 electrode exhibited a specific capacitance of 443 F g−1 at 5 mV s−1 scan rate. Additionally, liquid configured an asymmetric device was designed using Multiwalled carbon nanotubes (MWCNT) combined with Cu3V2O8, yielding a specific capacitance of 116 F g−1 at 5 mV s−1 with an energy density of 8.43 Wh kg−1 and a power density of 345.4 W kg−1, while maintaining capacitance retention of 76 % even after 4000 cycles as stability test. This work highlights the potential of Cu3V2O8 based materials for excellent performance of new avenues for energy storage.

Enhancement of photodetector performance of aluminum-doped zinc oxide thin films fabricated via SILAR method: Structural, optical, and electrical analysis

This study presents a comprehensive analysis of the structural, optical, electrical, and photosensing characteristics of aluminum-doped zinc oxide (Al:ZnO) thin films, fabricated via successive ionic layer adsorption and reaction (SILAR) techniques. The Raman and X-ray diffraction (XRD) analyses validated the hexagonal wurtzite structure and revealed that Al doping enhances crystallinity and crystal growth of ZnO. The average crystallite size increased from 21.6 nm in undoped sample to 23.8 nm in 5.0 wt% Al-doped sample, while strain effects decreased from 4.67 × 10-3 to 4.36 × 10-3. Scanning electron microscopy (SEM) images revealed improved film morphology and more defined geometries with increased Al doping, while energy-dispersive X-ray analysis (EDAX) confirmed successful Al integration into the ZnO lattice. Optical analyses indicate a narrowing of the ZnO bandgap to 2.81 eV in 5.0 wt% Al:ZnO from 3.02 eV in the undoped variant, while photoluminescence (PL) peak positions remains unchanged. Time-resolved fluorescence (TRF) indicated a reduction in electron lifetime with higher Al doping. Furthermore, Hall effect assessments reveal a decrease in carrier mobility and electrical resistivity, alongside a rise in carrier concentration with higher Al content. The photodetection efficacy was substantially improved with Al doping, particularly at 2.5 wt% Al, achieving a responsivity of 42.5 × 10-2 A/W, external quantum efficiency of 99.3 %, and detectivity of 1.8 × 1011 Jones. These findings exhibit that Al-doping substantially enhances the photodetection properties of ZnO thin films.

Facile SILAR deposited SnS/NiS vertical heterojunction for high performance flexible broadband photodetector

Low-cost, flexible broadband photodetectors fabricated from two-dimensional transition metal chalcogenides have garnered attention because of their excellent absorption coefficient and photoconductivity. Likewise, vertical heterojunctions fabricated from two two-dimensional (2D) transition metal chalcogenides (TMCs) also have drawn major curiosity lately owing to their superior optical performance. This work reports a p-p type II vertical Van der Waal's heterojunction structure by depositing thin film of NiS over SnS on a flexible paper substrate. Morphological and structural characterization confirms presence of a rhombohedral β-NiS crystal structure along with traces of Ni(OH)2 on orthorhombic SnS nanoparticles. The device fabrication method made use of the inexpensive, clean room free SILAR (Successive Ionic Layer Adsorption and Reaction) technique. A purposeful modification of narrow bandgap property of NiS is done by depositing it in an alkaline environment. The fabricated device records optical responsivity of 0.92 mA/W under UV illumination, 5.32 mA/W under Visible illumination, and 0.8 mA/W under NIR illumination. A maximum EQE of 1.3 % is observed along with superior response times of 0.114 s (UV),0.103 s (Visible) and 1.34 s (NIR). The acquired photo response is due to superior absorption property of NiS in UV region and SnS in the visible and NIR region. The difference in fermi level between two materials causes efficient separation of the charge carriers that results in junctional electric field upon light illumination. The device underwent flexibility testing and shown exceptional resistance to bending force making it suitable for numerous applications like wearable healthcare monitoring, security purposes and flexible image sensors.

SILAR deposited Antiviral silver-doped Ceria nano-films

Amid the COVID-19 global pandemic, ceria nanomaterials (CN) have garnered renewed interest as potential antiviral agents due to their ability to generate reactive oxygen species (ROS) on their surfaces. Enhancing ROS generation through precise defect engineering is key to improving these antiviral properties. This can be achieved through various methods, such as altering nano-dimensions and doping. In this context, we report on silver-doped ceria thin films. We have employed a cost-effective SILAR (Successive Ionic Layer Adsorption and Reaction) method for ceria nano-film deposition, which offers excellent control over film thickness. Utilizing an Arduino-controlled layer-by-layer (LBL) setup, we achieved precise control over the deposition process. This method facilitated the easy doping of ceria nano-films with silver ions. The silver-doped SILAR ceria thin films of varying thicknesses were subjected to antibacterial testing against E. coli bacteria. The samples with the highest antibacterial activity were further tested for antiviral efficacy against Feline calicivirus. The 80 SILAR Layers Ag-Ceria sample exhibited the best activity, completely deactivating the viral titer (105). This sample, when further tested against OC43 coronavirus, demonstrated a >99% reduction in virus titer. The mechanisms underlying these antimicrobial properties were investigated using antioxidative testing assays.

Analyzing antimicrobial activity of ZnO/FTO, Sn-Cu-doped ZnO/FTO thin films: Production and characterizations.

In the developing field of nanotechnology, ZnO (zinc oxide) based semiconductor samples have emerged as the foremost choice due to their immense potential for advancing the development of cutting-edge nanodevices. Due to its excellent chemical stability, low cost, and non-toxicity to biological systems, it is also utilized in various investigations. In this study, the successive ionic layer adsorption and reaction (SILAR) method was used to generate FTO (fluorine-doped tin oxide)/ZnO, and tin (Sn)-copper (Cu)-doped ZnO thin films at varying concentrations on FTO substrates. After being stacked 40 times in varying concentrations on the FTO substrate, FTO/ZnO thin films and Sn-Cu-doped thin films were annealed at 300°C. Using Scanning Electron Microscopy (SEM) Energy Dispersive Spectroscopy-(EDS), the agar diffusion test, and the viability cell counting method, the minimum inhibitory concentration, structural properties, surface morphology, antibacterial properties, bacterial adhesion, and survival organism count of FTO/ZnO thin films and Sn-Cu-doped thin films were investigated. Both doped and FTO/ZnO films with varying Sn-Cu concentrations expanded harmonically on the FTO substrate, according to the SEM-EDS investigation. The doping concentration affected their morphological properties, causing changes depending on the doping level. Antibacterial activity was observed in the powder metals, but no antibacterial activity was found in the thin film form. The highest adhesion rate of bacterial organisms on the produced samples was observed when the FTO/ZnO/Sn-Cu doping rate was 1%. In addition, the lowest adhesion rate was observed when the FTO/ZnO/Sn-Cu additive ratio was 3%. RESEARCH HIGHLIGHTS: ZnO based semiconductors highlight significant potential in advancing nanodevice technology due to their chemical stability, cost-effectiveness, and biocompatibility. Employing the SILAR method, the study innovatively fabricates FTO/ZnO and Sn-Cu-doped ZnO thin films on FTO substrates, exploring a novel approach in semiconductor manufacturing. Post annealing at 300°C, the research examines the structural and surface morphological changes in the films, contributing to the understanding of semiconductor behavior under varying conditions. The study delves into the antibacterial properties of ZnO thin films, offering insights into the potential biomedical applications of these materials. SEM-EDS analysis reveals that doping concentrations crucially influence the morphological properties of ZnO thin films, shedding light on the optimization of semiconductor performance. Findings indicate a specific doping rate (1% Sn-Cu) enhances bacterial adhesion, while a 3% additive ratio minimizes it, suggesting implications for biomedical device engineering and antibacterial surface design.

Performance evaluation of SILAR deposited Rb-Doped ZnO thin films for photodetector applications

ZnO-based photodetectors (PDs) compose a remarkable optoelectronic device field due to their high optical transmittance, electrical conductivity, wide band gap, and high binding energy. This study examined the visible light photodetector performance of the pristine and Rubidium (Rb)-doped ZnO thin films. The influence of Rb doping amount (2, 4, and 6 wt% in solution) on the electrical, optical, and structural properties of the ZnO-based thin films produced by the Successive Ion Layer Adsorption and Reaction (SILAR) technique was analyzed. Structural analyses showed that all peaks correspond to hexagonal wurtzite structure with no other peak from Rb-based phases, suggesting the high quality of the crystalline pristine and Rb-doped ZnO thin films. The morphology of the thin films shows homogenous layers formed of nanoparticles where particle size was first decreased and then increased with the increasing Rb doping according to Scanning Electron Microscope (SEM) morphology analysis. Besides that, Raman spectroscopy analyses indicate that the phonon lifetimes of the ZnO-based thin films slightly increased due to the improvement of the crystal quality with the increasing amount of Rb in the SILAR solution. Photosensor measurements of the nanostructured pristine and Rb-doped ZnO thin films were measured at different light power intensities under the visible light environment. Photosensor properties were examined depending on the doping amount and light power density. In light of the literature review, our study is the first to produce Rb-doped ZnO thin films via the SILAR method, which has a promising potential for photosensor applications.Graphical

Effects of Rapid Heat Treatments on the Properties of Cu2O Thin Films Deposited at Room Temperature Using an Ammonia-Free SILAR Technique

We report herein the analysis of the properties of copper(I) oxide thin films deposited by an optimized ammonium-free successive ion layer adsorption and reaction (SILAR) technique. The Cu2O thin film deposition process was carried out at room temperature using copper acetate monohydrate, sodium citrate as complexing agent, and hydrogen peroxide as precursors of copper and oxygen ions, respectively. The harmless and easy-to-handle sodium citrate replaces the volatile NH4OH commonly employed as complexing agent in the SILAR technique for the deposition of metal oxide thin films. The optical, structural, morphological, and electrical properties of the as-deposited Cu2O thin films were studied as a function of the number of cycles during deposition, as well as their modifications produced by the effect of rapid thermal annealing (RTA) in vacuum in a temperature range of 200–250°C for 1 min, 3 min, and 5 min. The as-deposited thin films had cubic crystalline structure corresponding to the Cu2O phase as determined by x-ray diffraction (XRD), with a direct energy bandgap of 2.43–2.51 eV depending on the number of cycles, and electrical resistivity of the order of 103 Ω cm. The XRD and x-ray photoelectron spectroscopy (XPS) analysis of the Cu2O thin films treated by RTA demonstrated an increase of the crystal size with time and temperature of the RTA and reduction effects from Cu2+ to Cu1+ oxidation states. On the other hand, the RTA treatments also decreased their energy bandgap to 2.38 eV and electrical resistivity to 102 Ω cm. The high energy bandgap values of the Cu2O thin films were attributed to quantum confinement effects produced by their small crystal size in the range of 3.6–8.6 nm.Graphical

Influence of solution pH dependency on structure, optical with photoelectrochemical characteristics of SILAR deposited copper oxide thin films

Photoelectrochemical (PEC) technology is a promising approach for converting solar energy into chemical energy, offering significant potential for renewable energy applications. In this work, the CuO thin film was fabricated with different pH value in between 8.5 ± 0.1 and 10.5 ± 0.1 via Successive Ionic Layer Adsorption and Reaction (SILAR) method. The Effect of pH on thickness, structural, morphological, elemental composition and optical properties were investigated by using stylus profilometry, XRD, SEM, TEM, EDX, UV–vis and PL. The XRD results showed that as the pH increased, the crystallite size increased from 19.24 nm to 25.62 nm, with a monoclinic phase along the (111) direction. The CuO film deposited at pH value 10.5 ± 0.1 exhibit well defined identical particle with its size in the range between 200 and 300 nm was confirmed by SEM and TEM analysis. As the pH increased from 8.5 ± 0.1 to 10.5 ± 0.1, the CuO film bandgap (Eg) value reduced from 1.52 eV to 1.42 eV with indirect transition. The CuO photocathode deposited at pH 10.5 ± 0.1 shows maximum photocurrent density of 1.45 mA/cm2 at −0.1 V vs. RHE in 0.5 M Na2SO4 solution. Furthermore, the Electrochemical Impedance Spectroscopy (EIS) analysis shows, the CuO (pH 10.5 ± 0.1) electrode have higher conductivity value of 0.6862 S/cm compared CuO at pH 8.5 ± 0.1 (0.2779 S/cm) and CuO at pH 9.5 ± 0.1 (0.4646 S/cm) electrodes.

Design strategy of TiO2/AgInSe/CdS/CdSe/ZnS photoanode and optimization of CdSe nanoparticles layer for increasing the efficiency of quantum dot-sensitized solar cells

In this study, ternary AgInSe (AISe) quantum dots compound were synthesized using a novel chemical precipitation method followed by a controlled hydrothermal treatment. The as-prepared particles were deposited onto a mesoporous TiO2 substrate to be applied as the photoelectrode of quantum dot sensitized solar cells (QDSSCs). Two configurations of multilayer photoanodes i.e. the TiO2 NCs/AgInSe/CdS/ZnS and TiO2 NCs/AgInSe/CdS/CdSe/ZnS were fabricated and employed for higher photovoltaic performance. The co-sensitizing CdS and CdSe nanocrystals layers were synthesized and deposited through successive ionic layer adsorption and reaction (SILAR) and chemical bath deposition (CBD) techniques, respectively. The results revealed that the QDSSCs with TiO2 NCs/AgInSe/ZnS photoanode initially showed an efficiency of 0.45 %. Incorporating CdS NCs as a quasi-shell film increased the efficiency to 3.9 % in the optimized TiO2/AgInSe/CdS(3 cycle)/ZnS configuration. Adding CdSe nanocrystals over-layer did not improve the efficiency of corresponding cells due to the increased thickness and resistance. Instead, the TiO2/AgInSe/CdS(2 cycle)/CdSe(12 min)/ZnS photoanode resulted in the efficiency of 4.10 % with 34 % improvement. Using the sub-micron size TiO2 hollow spheres (HSs) as the light scattering layer created further light absorption and enhanced performance. It was shown that the photovoltaic parameters were increased to short circuit current density (Jsc) of 23.25 mA/cm2, open-circuit voltage (Voc) of 512 mV and overall efficiency equal to 4.55 %

Successive ionic layer adsorption and reaction grown silver nanoflowers as an efficient flexible SERS substrate

The detection limitations of surface-enhanced Raman spectroscopy (SERS) sensors largely depend on the nano tip structure, yet the methods for constructing it are often overly complex. Here, we introduce a method using successive ionic layer adsorption and reaction (SILAR) to synthesize silver nanoflowers (AgNFs) within and on the surface of soft cellulose filter paper. This synthesis relies on a redox reaction involving silver nitrate (AgNO3) and ascorbic acid (AA), with no surfactants or additional agents utilized. Key synthesis parameters were investigated, such as the molar concentration of reactants and the number of synthesis cycles performed. As a result, the detection limit for rhodamine 6G (R6G) using SERS approached 10−11 M when deposited on the optimally synthesized AgNFs sample, yielding a corresponding enhancement factor of 8.9 × 108. The growth mechanism of AgNFs was analyzed by examining morphological changes over the initial five reaction cycles, and differences in X-ray diffraction (XRD) peak intensity ratios of (111) and (200) among the samples were considered. These findings pave a way for the development of high performance, Ag-based flexible SERS substrates.

A Core/Shell Bi2S3/BiVO4 Nanoarchitecture for Efficient Photoelectrochemical Water Oxidation.

The construction of nanostructured heterostructure is a potent strategy for achieving high-performance photoelectrochemical (PEC) water splitting. Among these, constructing BiVO4-based heterostructure stands out as a promising method for optimizing light-harvesting efficiency and reducing severe charge recombination. Herein, we present a novel approach to fabricate a type II heterostructure of core/shell Bi2S3/BiVO4 using electrolytic deposition and successive ionic layer adsorption and reaction (SILAR) methods. We identify the type II heterostructure and the difference in fermi energy using UV-Vis spectroscopy, X-ray photoelectron spectroscopy, and PEC measurements. This redistribution of charges due to the fermi energy difference induces an interfacial built-in electric field from BiVO4 to Bi2S3, reinforcing the photogenerated hole transfer kinetics from BiVO4 to Bi2S3. The Bi2S3/BiVO4 heterostructure exhibits a superior photocurrent (6.0 mA cm-2), enhanced charge separation efficiency (85 %), and higher open-circuit photovoltage (350 mV). Additionally, the heterostructure displays a prolonged average lifetime of charge (1.63 ns), verifying this heterojunction could boost interfacial carriers' migration via an additional nonradiative quenching pathway. Furthermore, the lower photoluminescence (PL) intensity demonstrates the interfacial built-in electric field is beneficial for boosting charge migration.