Room Temperature Chemical Bath Deposition Research Articles

A thermochemical understanding of the factors that govern the growth of chemical bath deposition of Cu2O thin films

A simple room-temperature chemical bath deposition technique, inspired by the Felhling method, was used to deposit nanocrystalline cuprous oxide (Cu2O) thin films. The process involved a mixture of copper sulfate, sodium potassium tartrate, and sodium hydroxide. A thermochemical analysis explored how pH and complexing agent concentration affected Cu(OH)2 solubility and subsequent Cu2O growth using species repartition diagrams. The study is conducted by fixing the [tartrate]/[Cu] ratio at 10, while varying pH, deposition time, and temperatures from room temperature to 80 °C. While oxide nucleation and growth began at pH = 9, denser and more uniform films formed at pH = 10 and 11, corresponding to the co-existing domain of copper hydroxo and copper tartrate complexes. Notably, regardless of pH, temperature, or reducing agent, the Cu2O (111) facets appear to be selectively stabilized. The introduction of an aldehyde reducing agent such as glucose had little effect on the growth of Cu2O layers at room temperature but promoted the formation of Cu0 at 80 °C.

Copper sulfide nanosheet arrays constructed on copper skeleton for efficient elemental mercury immobilization from flue gas

The major challenge to use metal sulfide for elemental mercury (Hg0) immobilization from coal-fired flue gas is exploiting a facile and feasible pathway to achieve its fixed-bed application. In this work, copper sulfide (Cu7S4) nanosheet arrays anchored on copper skeleton as an efficient Hg0 trap with outstanding Hg0 sequestration performance was rapidly fabricated via a facile room-temperature chemical bath deposition method. After being impregnated in the polysulfide solution, the surface of copper foam was quickly oxidized and then converted into Cu7S4 nanosheet, which tightly adhered to the macro-porous copper foam. Benefitted from well arrayed Cu7S4 nanosheet, high-permeability structure, and uniform dispersion of active sites, the as-obtained Cu7S4/Copper foam favors for its application in Hg0 immobilization under a fixed-bed circumstance. These superiorities contribute to its outstanding Hg0 removal capacity of 38.32 mg g-1and adsorption rate of 6.06 μg g−1 min−1, far transcending that of commercial granular S impregnated activated carbon by magnitudes. This study not only developed an efficient Hg0 sorbent used in fix-bed scenarios but also illustrated a versatile strategy to rapidly functionalize metal skeletons with metal sulfides for vapor Hg0 immobilization from coal-fired flue gas.

Simple, inexpensive way of fabricating high quality Zn(O)S nanoparticles by varying pH

In this work, a simple, inexpensive room temperature chemical bath deposition is proposed to synthesize high-quality Zn(O)S nanoparticles of varied composition. The band gap of these nanoparticles is found to alter by varying their chemical composition. Through this study, the formation of quantum confined ZnS and ZnOS nanoparticles as a function of pH is confirmed. A possible mechanism for the formation of these nanoparticles with respect to pH is discussed here.

MoS2ultrathin nanoflakes for high performance supercapacitors: room temperature chemical bath deposition (CBD)

Homogeneous ultrathin nanoflakes of MoS2 thin films have been successfully developed by simple and low cost room temperature chemical bath deposition (CBD) method which further applied as electrode material for high-performance supercapacitors. The surface morphological analysis revealed uniform growth of MoS2 nanoflakes on whole substrate surface. Structural analysis confirms the formation of rhombohedral crystal structure of MoS2. The electrochemical performances were tested by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance techniques. Different electrolytes were tested in order to find suitable electrolyte for MoS2 thin films. In addition, the effect of electrolyte concentrations on supercapacitive properties of MoS2 thin film was investigated. Thus, MoS2 ultrathin nanoflakes electrode exhibits excellent electrochemical performances with maximum specific capacitance of 576 F g−1 at 5 mV s−1 and good cycling stability of 82% over 3000 cycles.

Facile synthesis of Ni nanofoam for flexible and low-cost non-enzymatic glucose sensing

A novel Ni nanofoam electrode has been fabricated by low-cost methods and applied for non-enzymatic glucose sensing. Ni(OH)2 nanowalls, prepared by room-temperature chemical bath deposition, were transformed into an ensemble of Ni nanoparticles (20–30nm in size) upon annealing in forming gas at 350°C, and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), temperature programmed reduction with hydrogen (H2-TPR) and surface area measurements. The Ni nanofoam was converted to the catalytic Ni(OH)2/NiOOH – necessary for non-enzymatic glucose oxidation – by cyclic voltammetry (CV) in NaOH electrolyte. The electrode fabricated on conducting glass substrate showed a glucose sensitivity of 2.37mA/cm2mM, a linear range of 0.01–0.7mM, a limit of detection (LOD) of 5μM, a fast response time (1s), and resistance to chloride poisoning. The glucose sensor also exhibited an excellent long-term stability (4% decrease in sensitivity after 64 days) and selectivity in the presence of common interfering species. The versatility of the preparation method was demonstrated in the fabrication of a flexible (plastic substrate) sensor with a sensitivity of 1.43mA/cm2mM. The ease of fabrication and the excellent properties of Ni nanofoam in glucose sensing make it promising for low-cost and wearable sensing applications.

Room temperature chemical bath deposition of cadmium selenide, cadmium sulfide and cadmium sulfoselenide thin films with novel nanostructures

A simple, convenient and low cost chemical synthesis route has been used to deposit nanostructured cadmium sulfide, selenide and sulfoselenide thin films at room temperature. The films were deposited on glass substrates, using cadmium acetate as cadmium ion and sodium selenosulfate/thiourea as a selenium/sulfur ion sources. Aqueous ammonia was used as a complex reagent and also to adjust the pH of the final solution. The as-deposited films were uniform, well adherent to the glass substrate, specularly reflective and red/yellow in color depending on selenium and sulfur composition. The X-ray diffraction pattern of deposited cadmium selenide thin film revealed the nanocrystalline nature with cubic phase; cadmium sulfide revealed mixture of cubic along with hexagonal phase and cadmium sulfoselenide thin film were grown with purely hexagonal phase. The morphological observations revealed the growth and formation of interesting one, two and three-dimensional nanostructures. The band gap of thin films was calculated and the results are reported.

Electrochromic and electrochemical supercapacitive properties of Room Temperature PVP capped Ni(OH)2/NiO Thin Films

Porous-structured Ni(OH)2 and NiO thin films are good materials to enhance the performance of electrochromic devices as they provide an easy pathway for electrolyte penetration required for the improvement of electrochemical (EC) activity. In this paper, we present the results of our room temperature chemical bath deposition (CBD) of highly porous nanostructured PVP-capped Ni(OH)2/NiO thin films. We investigate the effects of post-deposition thermal treatment and the contribution of the substrate surface on the morphological, structural and electrochemical properties of these films as well as the role of the capping agent during the film growth process. Randomly oriented and well interconnected nanorods of individual lengths of about 600nm were deposited on both stainless steel and Fluorine doped tin Oxide (FTO). The incorporation of PVP helps to moderate the size and length of the nanorods in the films as well as delayed the transformation of nickel hydroxide to oxide films. The optical density and the colouration efficiency obtained for the as-deposited (Ni(OH)2 films are 0.985 and 55.89cm2/C respectively. The highest specific capacitance of 1184.52F/g is obtained for the as-deposited film on stainless steel. We can deduce that the incorporation of PVP in the films enhanced the electrochemical capacitive properties of the Ni(OH)2 films to a very good extent.

Room temperature linker free growth of CdSe quantum dots on mesoporous TiO2: solar cell application

Room temperature chemical bath deposition (CBD) method was employed to anchor CdSe quantum dots (QD׳s) on mesoporous TiO2, exclusively without using linkers. The sizes of CdSe QD׳s were tuned simply by varying the deposition time in CBD method and uniform coverage of CdSe QD׳s on mesoporous TiO2 was achieved. The chemical approach provided in the present investigation is free from the post annealing treatment after the growth of QD׳s; essential to lower down the process cost. The red shift in absorption maxima was observed with respect to deposition time in the UV–vis spectra which strongly supports the size quantization effect. Finally, the synthesized CdSe sensitized TiO2 has successfully demonstrated the potential ability as a quantum dot sensitizer for solar cell application when illuminated with 50mW/cm2 intensity (air mass 1.5).

Room-temperature chemical integration of ZnO nanoarchitectures on plastic substrates for flexible dye-sensitized solar cells

ZnO nanoarchitectured anodes composed of the ZnO nanocactus array and the top ZnO particle layer are chemically integrated on ITO-PET substrates using a facile room-temperature chemical bath deposition method for dye-sensitized solar cells (DSSCs). In the absence of high-temperature post-treatment and mechanical compression, a notable efficiency of 5.24% is simply achieved in the flexible ZnO DSSC.

Nanocrystalline p-type-cuprous oxide thin films by room temperature chemical bath deposition method

Nanocrystalline cuprous oxide (Cu 2O) thin films were synthesized on amorphous glass substrate by using simple room temperature chemical route namely, chemical bath deposition (CBD) method. The deposition kinetics played important role to get good quality nanocrystalline films with uniform thickness. The structural, surface morphological, optical and electrical properties of the films were investigated. Crystallization and growth processes obtained micro-spherical shaped grains of Cu 2O due to agglomeration of smaller nanoparticles. An optical and electrical characterization was performed to study the optical band gap and type of electrical conductivity of the film.

Synthesis and characterization of cadmium hydroxide nano-nest by chemical route

A facile chemical route based on room temperature chemical bath deposition (CBD) was developed to deposit the Cd(OH) 2 nano-nest. The growth mechanism follows two-stage crystallization with initial growth of nucleation centers, followed by subsequent anisotropic growth. The nano-nest morphological evolution of Cd(OH) 2 on different substrates has been carried out. These films have been characterized by the techniques; such as X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), optical absorption, contact angle measurement and thermoelectric power (TEP) measurements. The X-ray diffraction study revealed that the as deposited film consists of cadmium hydroxide (Cd(OH) 2) phase. The nano-nest consisted of wires with nearly uniform in dimensions, with diameter around 30 nm and length of few microns. As-deposited Cd(OH) 2 film used in this study showed water contact angle of 66°. The optical bandgap was found to be 3.2 eV, with n-type electrical conductivity as confirmed from thermo-emf measurements.

Bismuth oxide thin films prepared by chemical bath deposition (CBD) method: annealing effect

Bismuth oxide thin films have been deposited by room temperature chemical bath deposition (CBD) method and annealed at 623K in air. They were characterized for structural, surface morphological, optical and electrical properties. From the X-ray diffraction patterns, it was found that after annealing a non-stoichiometric phase, Bi2O2.33, was removed and phase pure monoclinic Bi2O3 was obtained. Surface morphology of Bi2O3 film at lower magnification SEM showed rod-like structure, however, higher magnification showed a rectangular slice-like structure perpendicular to substrate, giving rise to microrods on the surface. The optical studies showed the decrease in band gap by 0.3eV after annealing. The electrical resistivity variation showed semiconductor behavior and from thermoemf measurements, the electrical conductivity was found to be of n-type.

Effect of annealing on chemically deposited Bi 2Se 3–Sb 2Se 3 composite thin films

A room temperature chemical bath deposition (CBD) method was developed to deposit Bi 2Se 3–Sb 2Se 3 composite thin films. The preparative parameters such as concentration of bismuth ions, concentration of antimony ions, volume ratio of bismuth and antimony, complexing agent and deposition time were optimized to get good quality Bi 2Se 3–Sb 2Se 3 composite thin film of terminal thickness 0.34 μm. These films were annealed in air at 175 °C for 4 h. The effect of annealing on structural, optical and electrical properties were studied. The X-ray diffraction (XRD) study reveals that films are of Bi 2Se 3–Sb 2Se 3 composite with individual Bi 2Se 3 and Sb 2Se 3 phases. Scanning electron microscopy (SEM) study for as-deposited films showed that films are well covered to the substrate surface with some surface roughness as seen from atomic force microscopy (AFM) image of as-deposited films. The surface morphology of the film is smooth and homogeneous with nanocrystalline grain size. The optical bandgap is found to be 1.6 eV for Bi 2Se 3–Sb 2Se 3 composite thin film which lies between bandgaps of Bi 2Se 3 and Sb 2Se 3, and slightly decreases after annealing. The room temperature dark electrical resistivity for Bi 2Se 3–Sb 2Se 3 composite thin film is found to be of the order of 10 5 Ω cm with n-type electrical conductivity was confirmed from thermo-e.m.f. study.

Wool scouring wastes for fertilizer purposes

Porous-structured Ni(OH)2 and NiO thin films are good materials to enhance the performance of electrochromic devices as they provide an easy pathway for electrolyte penetration required for the improvement of electrochemical (EC) activity. In this paper, we present the results of our room temperature chemical bath deposition (CBD) of highly porous nanostructured PVP-capped Ni(OH)2/NiO thin films. We investigate the effects of post-deposition thermal treatment and the contribution of the substrate surface on the morphological, structural and electrochemical properties of these films as well as the role of the capping agent during the film growth process. Randomly oriented and well interconnected nanorods of individual lengths of about 600 nm were deposited on both stainless steel and Fluorine doped tin Oxide (FTO). The incorporation of PVP helps to moderate the size and length of the nanorods in the films as well as delayed the transformation of nickel hydroxide to oxide films. The optical density and the colouration efficiency obtained for the as-deposited (Ni(OH)2 films are 0.985 and 55.89 cm2/C respectively. The highest specific capacitance of 1184.52 F/g is obtained for the as-deposited film on stainless steel. We can deduce that the incorporation of PVP in the films enhanced the electrochemical capacitive properties of the Ni(OH)2 films to a very good extent.