Chemical Bath Deposition Research Articles

Engineering Mn-Doped CdS Thin Films Through Chemical Bath Deposition for High-Performance Photoelectrochemical Water Splitting.

Doping conventional materials with a second element is an exciting strategy for enhancing catalytic performance via electronic structure modifications. Herein, Mn-doped CdS thin films were successfully synthesized with the aid of the chemical bath deposition (CBD) by varying the pH value (8, 10, and 12) and the surfactant amount (20, 40, 60 mg). Different morphologies like nano-cubes, nanoflakes, nano-worms, and nanosheets were obtained under different deposition conditions. The optimized Mn-doped CdS synthesized at pH=8 exhibited better photoelectrochemical (PEC) performance for oxygen evolution reaction (OER) than pure CdS films, with a maximum photocurrent density of 300 μA/cm2 at an external potential of 0.5 V, under sunlight illumination. The observed performance is attributed to the successful Mn doping, porosity, high surface area, and nanosphere morphology.

Co-deposition of CuO:ZnO Nanocomposite on n-Type Si Substrate by Chemical Bath Deposition (CBD) Technique for Photovoltaic Application

Co-deposition of CuO:ZnO Nanocomposite on n-Type Si Substrate by Chemical Bath Deposition (CBD) Technique for Photovoltaic Application

Photoelectrochemical Properties and Characterization of CdS/CdSe Heterojunctions Obtained by CBD on ITO and p–Si Substrates

AbstractThis research investigates the optical, structural, electrical, and photoelectrochemical characteristics of CdS/CdSe heterojunctions formed on both ITO and p–Si substrates. The deposition of CdS and CdSe films was carried out using the chemical bath deposition method, which is economical and simple method. The optical, structural, and electrical properties of CdS/CdSe heterojunctions were analyzed through UV–Vis spectrometry, photoluminescence (PL) spectroscopy, field emission–scanning electron microscopy (FE‐SEM), X‐ray diffraction (XRD), Raman spectroscopy, and Hall‐effect measurements. Furthermore, Mott–Schottky analysis was employed to investigate the electrochemical properties of the semiconductor CdS/CdSe heterojunctions on both ITO and p–Si substrates. Additionally, the photoelectrochemical investigations of CdS/CdSe heterojunctions on ITO and p–Si substrates were conducted by electrochemical analyses using linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), and photocurrent – time plots under both dark and illuminated conditions.

Function‐Oriented Design of Amorphous MoS2 with Abundant Active Sites for High‐Efficiency Hydrogen Evolution Reaction

AbstractMolybdenum disulfide (MoS2) has received great interest as a highly active and cost‐effective electrocatalyst for hydrogen evolution reaction (HER). However, a main challenge for developing high‐efficiency electrocatalysts is to tailor the factors affecting the HER performance, such as composition, structure, and morphology. Herein, amorphous MoS2 electrodes with different Mo and S contents are successfully synthesized by the chemical bath deposition method using different molar ratios of Mo/S precursors (Mo/S: 4 : 1, 1 : 1 and 1 : 4) at various growth times. Experimental results indicate that the composition and the surface morphology of MoS2 are strongly sensitive to the Mo and S contents, which can create different surface roughness at the interface induced by growth times. The as‐prepared MoS2 electrode with a molar ratio of 1 : 4 exhibits superior HER activity in 1 M KOH, only requiring low overpotentials of 220 mV at 20 mA cm−2, which is much lower than those of MoS2 with a molar ratio of 1 : 1 (253 mV), and 4 : 1 (290 mV), respectively. This outstanding electrochemical performance of MoS2 (Mo/S, 1 : 4) with excellent long‐term stability can be attributed to its unique sulfur‐rich MoS2 nanosheet array structure with exposed abundant active sites, a high electrochemical active surface area (ECSA: 955.50 cm2) and superior roughness factor (RF: 3822).

Cost‐Effective Transparent N‐Doped Tin Oxide Electrodes with Excellent Thermal and Chemical Stabilities Enabling Stable Perovskite Photovoltaics Based on Tin Oxide Electron Transport Layer

AbstractPerovskite solar cells (PSCs) incorporating chemical‐bath‐deposited (CBD) SnO2 layers have garnered considerable attention because they combine high electron mobility and low‐temperature processing, affording remarkable photovoltaic performance. However, the acidic conditions of CBD limit its compatibility with front transparent electrodes (FTEs). Herein, cost‐effective, thermally stable, and highly transparent nitrogen‐doped SnO2 (NTO) FTEs tailored to integrate with CBD‐SnO2‐based PSCs are developed. By precisely controlling the N dopant content in the magnetron sputtering process, a NTO FTE with a sheet resistance of 38.64 Ω/square, an optical transmittance of 86.17%, a smooth surface morphology (1.2 nm), and mechanical flexibility is obtained. Furthermore, doping N in SnO2 imparts thermal and chemical stability superior to those of conventional Sn‐doped In2O3 (ITO) electrodes. Additionally, a well‐matched energy band of NTO with a SnO2 electron transport layer (ETL) and homogeneous interfaces is a critical advantage. By implementing this multifaceted strategy using a novel low‐cost NTO FTE, CBD‐SnO2‐based PSCs with elevated open‐circuit voltages and energy‐barrier‐free characteristics are fabricated. A champion power conversion efficiency of 20.43% is achieved, and 93.30% of the initial efficiency is retained even after 3 000 h without encapsulation. This integration of a NTO FTE with a SnO2 ETL paves the way for robust and long‐lasting high‐performance PSCs.

EFFICIENT SYNTHESIS OF ZNO AS AN ELECTRODE OF PIEZOELECTRIC NANOGENERATORS

Piezoelectric nanogenerators (NGs) hold immense promise as self-powered devices for harvesting mechanical energy from the environment. This study introduces an efficient and scalable synthesis method for zinc oxide (ZnO) nanorods, a pivotal material in piezoelectric nanogenerators (NGs), with several key results. A Chemical Bath Deposition technique is employed, optimizing parameters such as growth time, temperature, and precursor concentrations to achieve well-aligned and high-quality ZnO nanorods. The structural and morphological characteristics of the synthesized nanorods are systematically investigated using advanced characterization techniques. The synthesized ZnO nanorods exhibit an average length of 400nm, demonstrating their slender shape. Furthermore, the study determines an energy gap value of 3.5 eV for multilayer zinc oxide thin films, indicating the transition from the valence band to the conduction band. Notably, thermal annealing at 500°C leads to a substantial increase in average output voltage, reaching 1.95 V, a fourfold improvement compared to as-deposited nanopowders. These findings emphasize the efficiency and potential of the proposed synthesis method and underscore its practical applications in enhancing energy harvesting capabilities for sustainable power generation from mechanical sources in piezoelectric NGs.

Thorough investigation of the optical, electrical and thermal properties of Cu3Se2 thin film deposited by chemical bath deposition

Recently, metal chalcogenide thin films have gained utmost significance across various industries attributed to their exceptional versatility and efficiency in advancing future electronics, optoelectronics and energy conversion devices. In this work, the formation of a copper selenide (Cu3Se2) thin film is accomplished through the utilization of chemical bath deposition approach. The energy dispersive analysis of X-ray and X-ray photoelectron spectroscopy confirmed the chemical composition stoichiometry for the as-deposited Cu3Se2 thin film. X-ray diffraction analysis conclusively validates the tetragonal unit cell structure. The homogenous and crack-free film deposition is verified employing optical microscopy, scanning electron microscopy, and atomic force microscopy analysis. The crystalline character of the thin film is ascertained by the evident appearance of lattice fringe patterns in high-resolution transmission electron microscopy along with the distinctive spot patterns perceived in the selected area electron diffraction pattern. The optical reflectance spectrum revealed a direct bandgap of 1.77 eV. The Raman spectrum exhibited a solitary peak at 259 cm−1 that corresponds to the Ag1 vibrational mode of the Cu-Se phase. The comprehensive electrical transport property for the as-deposited thin film is accomplished through the control assessment of temperature-dependent d.c. electrical resistivity and photoresponse current-voltage profiles. The investigation of the thermal decomposition of the Cu3Se2 thin film is conducted via thermogravimetry, utilizing the non-mechanistic Kissinger method to extract kinetic parameters from the thermal dataset. The acquired outcomes are thoroughly examined in this manuscript.

Effect in variation of the cationic precursor temperature on the electrical and crystalline properties of MnS growth by SILAR

The crystallographic, optical, and electrical properties of manganese sulfide thin films depend on the control of the temperature precursors in the synthesis process, as shown by the results of this work. MnS thin films were deposited on glass substrates using the SILAR method and over an additional layer of CdS synthesized by chemical bath deposition (CBD) to acquire a p-n heterojunction. SILAR is an inexpensive method performed with a homemade robot in this case. Temperature in the solution precursors varied from 20 to 80 °C in four experiments. The morphology and structure of MnS and FTO/CdS/MnS thin films were studied through scanning electron microscopy (SEM) and grazing-incidence X-ray diffraction (GIXRD); the results indicate that materials showed a polycrystalline behavior, a diffraction peak of α- MnS cubic phase was observed with lattice constants values, ranging from 4.74 to 4.75 Å.Additionally, Raman spectroscopy showed a signal corresponding to the transversal optical phonons of MnS at a wavenumber near 300 cm−1. UV–vis spectroscopy showed optical bandgap values of 3.94, 4.0, 4.09, and 4.26 eV for thin films obtained at 20°, 40°, 60°, and 80 °C.respectively. Results indicated 80 °C as an optimal cationic precursor process temperature, achieving optical transmittance T% and good film quality according to SEM and GIXRD for the synthetization of MnS. The current–voltage (I–V) characterization in the heterojunction showed a characteristic diode curve with an open circuit voltage (VOC) of 300 mV under illumination, which indicated that the manganese sulfide behaves as p-type material contributing with positive charge carriers, while CdS behaves as n-type material.

Impact of Rhodamine B solution on charge carrier generation and photocatalytic performance in CdS/TiO2 heterostructures synthesized by CBD.

This article presents the study of Rhodamine B solution effects on the generation of charge carriers and the photocatalytic performance of CdS/TiO2 heterostructure films. CdS/TiO2 heterostructure films were synthesized using the chemical bath deposition technique (CBD). The structure and morphology of the heterostructures were studied by X-ray diffraction (XRD), and Scanning Electron Microscope (SEM), respectively. The optical properties of the CdS/TiO2 heterostructures were characterized using a UV–vis spectrophotometer. The results showed that the CdS/TiO2 optical band gap energy (Eg) was 2.75 eV, between the TiO2 band gap energy (3.38 eV) and the CdS band gap energy (2.57 eV). The electrochemical characterization indicated that the photocurrent of the CdS/TiO2 heterostructure decreased from 29 mA to 12.4 mA when the UV-vis light source was turned off. The density of charge carriers generated on the surface of the CdS/TiO2 was simulated employing the WXAMPS software. The results suggest that the thickness of the TiO2 layer should be optimized to allow the activation of CdS. Finally, this study concludes that the presence of rhodamine B in the solution attenuates light transmission and affects the generated electron-hole pairs, resulting in poor photocatalytic behavior.

Optical and electrical properties of Ni+2 doped nanocrystalline Bi2S3 thin films prepared by chemical bath deposition method

Nickel (Ni+2) doped nanocrystalline Bi2S3 thin films are deposited on the glass substrate from the solutions containing Bismuth Nitrate, Ethylenediamine Tetraacetic acid (EDTA) and Thioacetamide at a bath deposition temperature of 318K. The optical, surface morphological and electrical properties of Ni-doped Bi2S3 thin films prepared at three different doping concentration are investigate by using ultraviolet–visible transmission spectra (UV–Vis), Scanning electron microscopy (SEM), Energy Dispersive X-ray (EDAX) and thermo-e.m.f. techniques. The optical band gap energies are found in between 2.32-2.43 eV. The SEM images show that the prepared films are continuous, dense and distributed over the entire area with good uniformity. The electrical conductivity of the films are in the order of 10-2 Ω-1 m-1 . The films are n-type as determined from the Hot Probe method. Photoconductivity studies reveal that photocurrent increases with the increase in Ni doping concentrations. Due to the absorption of photons, free electron-hole pairs (EHP) are produce.

Synthesis of Template-free Flower-like ZnO Nanorods using a Simple Chemical Bath Technique

Flower-like ZnO nanorods were successfully synthesised using a template-free, low-temperature chemical bath deposition method. The effects of growth time on the structural, morphological, and vibrational properties of flower-like zinc oxide were investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicated that the crystallite size and density of flower-like ZnO nanorods increased with increasing growth time. Raman spectroscopy confirmed the existence of specific Raman modes that correspond to the wurtzite structure of ZnO. In addition, Raman measurements revealed that increased growth time increases the Raman modes intensity of the flower-like ZnO nanorods. Moreover, the measurements of the Au/ZnO nanorods/FTO Schottky diode showed that all devices functioned as Schottky diodes and rectifying; however, their ideality factor was greater than 1. In addition to the ideality factor, the Schottky barrier height was calculated and slightly increased with growth time. The values of Schottky barrier height obtained were 0.502 eV, 0.523 eV, 0.516 eV and 0.529 eV for samples grown at 1, 2, 3 and 4 h, respectively.

Cauliflower-based cadmium sulfide prepared through micro spot fabrication with laser-assisted chemical bath deposition as an active area for optical photosensors

The study aimed to synthesize cadmium sulfide (CdS) thin films into metal-semiconductor-metal (MSM) structured optical photosensors using laser-assisted chemical bath deposition (LACBD) on a silver-coated glass substrate. The CdS nanocauliflowers (NCFs) were synthesized under the influence of laser exposure and showed superior electric, optic, and structural qualities. The CdS NCFs had an average length of 365.7 ± 100 nm. were extremely well-crystallized with a band gap of 2.41 eV. The LACBD method promoted the formation of a well-crystallized, super-CdS layer. The device exhibited a visible-light photosensitivity of 236.80% and a quantum efficiency of 4.2 × 104, demonstrating its exceptional sensitivity and stability in visual detection. The study highlights the potential of LACBD to synthesize high-quality CdS thin films for optoelectronic device applications

Investigating the effects of varying sulfur concentration on ZnSxSe1-x (0 ≤ x ≤ 1.0) thin films prepared by photo-assisted chemical bath method

Zinc sulfur-selenide (ZnSxSe1-x) (0 ≤ x ≤ 1.0) thin films were grown on glass substrates using photo-assisted chemical bath deposition technique and the deposited samples were annealed in an open-air furnace at 250 ℃ for 3 h. X-ray diffraction analysis revealed a phase transition from hexagonal ZnSe to cubic ZnS as x changes from 0 to 1.0. Raman scattering showed two longitudinal optical modes due to ZnSe structure. The effects of S and Se ions variation is observed by the change in surface morphology from nanoflakes to spherical particles as x increased. The presence of the expected elementary composition was confirmed by the energy dispersive x-ray spectroscopy. The bandgap of the films was found to increase from 2.68 to 3.50 eV with a corresponding decrease in crystallite size (11.9 – 7.1 nm) as x varied from 0 to 1.0. Photoluminescence excitation and emission showed defect emission peaks ascribed to intrinsic and extrinsic deep level defects such as Zn2+ or S2- ions vacancies and interstitials. The emission colours were tuned from red to yellowish-green with increased x values as confirmed from Commission Internationale de L’Eclairage analysis. The tunability of the ZnSxSe1-x structural, optical and morphological properties makes it a good candidate for optoelectronic applications.

Optical transmission and photoconductivity of chemical bath-deposited CdS thin films for optoelectronic applications

This paper presents a comprehensive study of the optical transmission, photoconductivity, and morphology of CdS thin films deposited via the chemical bath deposition (CBD) method. The films deposited for 60 min exhibit an optical energy band gap value of 2.42 eV and the highest optical transmission of 75 % in the wavelength range of 500–900 nm. For these films, the transmission electron microscopy imaging shows a distribution of particle sizes around 10 nm. The wavelength dependence of the photoconductivity, extracted from photo resistivity data, shows that the maximum photoconductivity occurs at 492 nm wavelength. This corresponds to an electrical energy band gap of 2.52 eV, which is greater than the optically measured energy gap of 2.42 eV. Based on these results, the electron-hole pair binding energy for CdS films is estimated as 100 meV. According to the electrical resistivity vs. temperature measurements, the activation energy is 1.26 eV which agrees with the electrical energy band gap of 2.52 eV. CdS films annealed under nitrogen gas at 200 °C for one hour exhibited an energy gap of 2.32 eV. These films displayed a conductivity of 60 × 10−4 Scm−1, a carrier concentration of 6.38 × 1014 cm−3, and a mobility of 7.46 cm2 V−1 s−1. These impressive characteristics suggest the suitability of CBD-grown CdS films annealed at 200 °C in nitrogen gas, to be used as the window material in CdS/CdTe thin film solar cells and other optoelectronic applications.

Effect of N2/I2 atmosphere annealing sensitization on PbSe-based photodetector for NIR photodetection

Lead selenide (PbSe) detectors have garnered widespread utility in infrared detection due to their advantages of low-Russian compounding and uncooled operation. In this study, PbSe thin films were firstly deposited on glass using selenourea (SeC(NH2)2) as the selenium source by chemical bath deposition. The changes in morphology, composition, structure, and photoelectric properties of PbSe films thermally sensitized in 4 atm of O2, N2, O2/I2, and N2/I2 were investigated. It was discovered that PbI2 was supplied to the film surface following thermal sensitization in the I2 atmosphere to create a PbSe/PbI2 separation model, promoting photogenerated charge separation and enhancing PbSe optoelectronics' performance. The device's dark current is decreased to 1/136 before annealing, the on-off ratio is increased by 18.7 times, the reaction time is only a few tens of μs, and the response speed is increased by 105 times after N2/I2 thermal sensitization.

Role of triethanolamine complexing agent in chemical bath deposition of tin sulfide thin films: Microstructural and optical properties

This paper reports the experimental results studying the structure, optical and dielectric properties of tin monosulfide thin films. Tin monosulfide (SnS) films were deposited on glass substrate by chemical bath deposition to study the role of triethanolamine (TEA: complexing agent) concentration on the film properties. X-ray diffraction spectra reveal that the films exhibit mainly cubic phase which remain stable over the range of TEA concentration (3.0 M − 5.0 M). FTIR spectra indicate the S-Sn bond stretching in all films. Raman spectroscopy analysis shows the presence of minor trace of secondary SnS2 phase (along with main cubic π-SnS phase) in all films. SEM micrographs show cauliflower-like surface morphology of all films. Optical results reveal that the films possess high value of absorption coefficient (≥105 cm−1) in the visible region. Direct optical transition behavior is observed in all films. From Tauc plots, the calculated optical band gap (Eg) varies from 1.79 eV to 1.91 eV with the variation in TEA concentration. The dielectric constant, refractive index and an extinction coefficient are also calculated and observed to decrease with increasing TEA concentration. Experimental results suggest that an appropriate concentration of a complexing agent (TEA) can be chosen to obtain crystalline films without deterioration of crystalline structure and phase, not effecting Eg significantly.

Synthesis and characterization of Mo-doped PbS thin films for enhancing the photocatalytic hydrogen production

Photocatalytic hydrogen production has gained considerable attention as a sustainable method for renewable energy production. Lead sulfide (PbS) compound has significant reserves and a suitable bandgap for the production of hydrogen gas via the water photo-splitting process. However, the charge recombination effect of the charge carriers severely limits their potential use in solar water splitting. Herein, the photoelectrodes of PbS were fabricated through the chemical bath deposition method and then doped with different Mo concentrations to optimize the hydrogen photo-production activity. Both structural and performance characterizations of the photoelectrodes have been carried out using various characterization techniques. The photoelectrochemical (PEC) performance of molybdenum (Mo)-doped PbS photoelectrodes exhibits a significant increase in the photocurrent density with the optimum photocurrent density of 1.2 mA/cm2 obtained at 0.8 % Mo doping atomic ratio which was twelve times higher than that of a pure PbS photoelectrode. The doping of Mo induces the electron-hole separation yield which results in improved electron transport characteristics. The Mo doping was as act as a donor site that increased the PbS film conductivity. The newly optimized Mo–PbS was used as a promising photoelectrode supported on commercial glass using the optimum Mo-doped PbS photoelectrode, the photoelectrochemical (PEC) hydrogen production rate was reached 122 μmol/h cm2 during the solar water splitting process and the conversion efficiency of the incident photon-to-current (IPCE) value was 7.0 % at 390 nm monochromatic exposure. Moreover, the stability of the optimum electrode was evaluated as a function of the number of runs and exposure time in addition to the electrochemical impedance study.

EFFECT OF DEPOSITION PARAMETER ON EXTERIOR MORPHOLOGY, STRUCTURAL AND OPTICAL CHARACTERISTICS OF CHEMICAL BATH-DEPOSITED ZINC OXIDE THIN FILMS

In this research, Zinc Oxide thin films (ZOTF) have been placed onto a glass substrate at different times of deposition via chemical bath deposition (CBD) technique. The influence of deposition time (DT) on the exterior morphology, elemental, structural and optical behaviors of the prepared thin films has been studied through various characterization techniques for example field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD) analysis and UV-Vis spectroscopic analysis, respectively. According to FESEM images, the thin film surface existing on a dense and flower-like surface morphology was changed to flake-like structure due to increase of DT. EDX analysis exhibited the mass % and atomic % of Zn which is extant in greater proportion but O is lesser in the prepared ZOTF. The XRD pattern exposed the hexagonal wurtzite structure of ZOTF. The UV-V is results exhibited a decrease in transmittance and the optical band gap was significantly influenced by the alteration of DT. The observed high transparency of these thin films in the visible region makes them appropriate for utilization as transparent windows in numerous optical device applications.

Solution‐based fabrication of copper oxide thin film influence of cobalt doping on structural, morphological, electrical, and optical properties

In this study, Cobalt (Co) doped Copper Oxide (CuO) films at different concentrations were deposited on glass substrates, using the Chemical Bath Deposition (CBD) method. The films were characterized by Field Emission Scanning Electron Microscopy (FESEM), X-Ray Diffraction (XRD), Ultra Violet-Visible Spectroscopy (UV-Vis.) and two-point contact method. The FESEM images showed that nanoplates formed increased in size and voids on the films surface decreased with increasing Co concentration. The XRD patterns revealed an increase in crystallite size with increasing (from 14.40 to 18.60 nm) Co concentration and no secondary phase was formed. The Energy-dispersive X-ray spectroscopy (EDS) spectra showed the presence of Co in the film composition with increasing concentration. The results of UV-Vis. spectroscopy showed that band gap values could be changed with Co doping and thus the CuO band gap could be adjusted with the Co doping. The temperature-dependent current-voltage measurement results obtained with the two-point contact method showed that activation energy levels increased (from 0.134 to 0.232 eV) with increasing Co concentration. It was also observed that the conductivity increased with increasing temperature.

Pain-Free Alpha-Synuclein Detection by Low-Cost Hierarchical Nanowire Based Electrode.

Analytical methods for the early detection of the neurodegenerative biomarker for Parkinson's disease (PD), α-synuclein, are time-consuming and invasive, and require skilled personnel and sophisticated and expensive equipment. Thus, a pain-free, prompt and simple α-synuclein biosensor for detection in plasma is highly demanded. In this paper, an α-synuclein electrochemical biosensor based on hierarchical polyglutamic acid/ZnO nanowires decorated by gold nanoparticles, assembled as nanostars (NSs), for the determination of α-synuclein in human plasma is proposed. ZnO NSs were prepared by chemical bath deposition (CBD) and decorated with electrodeposited Au nanoparticles (Au NPs). Then, electro-polymerized glutamic acid was grown and functionalized with anti-α-synuclein. A synergistic enhancement of electrode sensitivity was observed when Au NPs were embedded into ZnO NSs. The analytical performance of the biosensor was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), using the Fe(II)(CN)64-/Fe(III)(CN)63- probe. The charge transfer resistance after α-synuclein recognition was found to be linear, with a concentration in the range of 0.5 pg·mL-1 to 10 pg·mL-1, a limit of detection of 0.08 pg·mL-1, and good reproducibility (5% variation) and stability (90%). The biosensor was also shown to reliably discriminate between healthy plasma and PD plasma. These results suggest that the proposed biosensor provides a rapid, quantitative and high-sensitivity result of the α-synuclein content in plasma, and represents a feasible tool capable of accelerating the early and non-invasive identification of Parkinson's disease.