ZnSe and ZnS nanocrystals (NCs) were precipitated in glasses through heat-treatment. High resolution transmission electron microscope image confirmed that ZnSe NCs were formed in the silicate glasses, and the X-ray diffraction patterns confirmed that ZnS NCs were precipitated in the borosilicate glasses. Absorption shoulders of the ZnSe NCs and ZnS NCs appeared at ~ 2.76 eV and ~ 3.78 eV, corresponding to the bandgap energies of bulk ZnSe and ZnS crystals, respectively. Instead of the intrinsic emissions, broad-band visible photoluminescence from the surface defects or color centers in the glasses was observed from these ZnSe or ZnS NCs.

Formation and optical properties of ZnSe and ZnS nanocrystals in glasses

Nanocrystalline titania films deposited on FTO transparent electrodes were sensitized by CdS nanoparticles synthesized in situ by the SILAR method. Three precursor solutions were employed for adsorption of Cd2+ ions: nitrate, sulfate, and acetate. The CdS load and the size of CdS nanoparticles varied a lot from one precursor to the other. The highest load and the largest nanoparticles were obtained in the case of cadmium acetate, the smallest in the case of nitrate, while sulfate gave intermediate values. Ultraviolet photoelectron spectroscopy was employed to measure the ionization potential (and valence band potential) for pure titania and for sensitized titania in the three cases. The obtained values were 7.4 eV for pure titania and 6.7, 6.6, and 5.7 eV for CdS-sensitized titania made by using cadmium nitrate, sulfate, and acetate precursors, respectively. The corresponding band gap values ranged between 2.5 and 2.3 eV. The thus characterized photoanodes were employed to make Quantum Dot Sensitized Sola...

Effect of the Nature of Cadmium Salts on the Effectiveness of CdS SILAR Deposition and Its Consequences on the Performance of Sensitized Solar Cells

The effect of deposition time on the structural, morphological and optical band gap of lead selenide thin films synthesized by chemical bath deposition method

Al-doped ZnS thin films: Physical and electrochemical characterizations

Comprehensive optical studies on Ga-doped ZnS thin films synthesized by chemical bath deposition

The effect of various complexing agents on the morphology and optoelectronic properties of chemically deposited ZnS thin films: A comparative study

Effect of deposition time on optical and luminescence properties of ZnS thin films prepared by photo assisted chemical deposition technique

In the present work, lead sulphide thin films have been grown on soda lime glass substrates by chemical bath deposition technique using three different complexing agents, namely triethanolamine, diethanolamine and hexamine. Aqueous solutions of lead acetate complexed with the above mentioned ligands were used as cationic precursor and thioacetamide as anionic precursor. The structural, morphological, optical and electrical properties of the as-prepared samples were investigated and compared by means of X-ray diffraction (XRD), Scanning electron microscopy (SEM), optical and electrical studies. The films were well crystallized and highly adherent to the substrate with face centered cubic structure. The average crystallite size was found to be in the range 15-20nm. The SEM micrographs showed variations in morphology. Optical studies revealed that the direct band gap energy was in the range of 1.65-2.27eV. The transmittance and reflectance in IR region was respectively in the range of 14%-47% and 25-45%. Optical constants of all films were determined by absorbance and reflection measurements. The room temperature conductivity of the PbS thin films were in the range 9.67×10−9 (Ω-Cm)−1-3.29×10−6(Ω-Cm)−1. The optical band gap energy has inverse relation with grain size and electrical conductivity is closely related to structural parameters like grain size, crystallinity and microstrain. PbS thin film using hexamine as complexing agent was proved to be the best in structural, optical and electrical properties. In this attempt we establish that the use of different complexing agents have immense effect on structural, morphological, optoelectronic and transport properties of PbS thin films.

https://iopscience.iop.org/article/10.1088/1757-899X/73/1/012086/pdf

Role of complexing agents on chemicalbath deposited PbS thin film characterization

Thin films of Lead sulphide (PbS) were grown on soda lime glass substrate by Successive Ionic Layer Adsorption and Reaction (SILAR) method using lead acetate, lead chloride, lead nitrate, and lead sulphate as cationic precursors and thioacetamide as sulphur source. The experiments were carried out at room temperature under normal pressure utilizing aqueous conditions. The structural and morphological aspects of the as prepared samples were investigated by means of XRD and SEM results. The prepared samples were polycrystalline with nanometer-sized grains and identified as galena type cubic structure (FCC). The values of average crystallite size were found to be in the range 22 to 30 nm. The SEM micrographs show variations in morphology. Optical studies revealed that the absorption edges of the films indicated strong blue shifts with respect to bulk sample. In this work, we establish that the cationic precursor sources and in turn the size of the crystallites affects the structural, morphological and optical properties of PbS thin films.

http://iopscience.iop.org/article/10.1088/1757-899X/43/1/012009/pdf

The role of cationic precursors in structural, morphological and optical properties of PbS thin films

Photoassisted chemical deposition is a customized form of chemical bath deposition where the reaction is carried out in the presence of ultraviolet light. Deposition of tin sulfide films was carried out by this method using two different chemical baths. The as-prepared samples from the acetone bath were crystalline, exhibiting the orthorhombic structure of the Sn2S3 phase, but those from the glacial acetic acid bath were amorphous. The crystallinity of the films was improved on annealing. The deposition rate was found to depend on the pH of the bath and the chemical formulation. Distinct morphology was obtained for as-grown films. The films from the acetone bath were compact with uniform morphology of needle-shaped grains having equal diameters and lengths. The films from the glacial acetic acid bath were similar, with smaller needles. The high absorption coefficients of as-grown and annealed films show their potential application as absorber layers in photovoltaic devices. The refractive index was estimated from the reflectance of the films. The estimated activation energies of the as-prepared films from the acetone and glacial acetic acid baths were 0.4 eV and 0.46 eV, whereas those of the annealed samples were 0.2 eV and 0.44 eV, respectively. The activation energy was found to decrease for annealed films due to a decrease in trap sites.

A. C. Dhanya

Papers

The effect of various complexing agents on the morphology and optoelectronic properties of chemically deposited ZnS thin films: A comparative study

Effect of deposition time on optical and luminescence properties of ZnS thin films prepared by photo assisted chemical deposition technique

Role of complexing agents on chemicalbath deposited PbS thin film characterization

The role of cationic precursors in structural, morphological and optical properties of PbS thin films

Photoassisted Chemically Deposited Tin Sulfide Thin Films Based on Two Different Chemical Formulations