An effective CdS/Ti-Fe2O3 heterojunction photoanode: Analyzing Z-scheme charge-transfer mechanism for enhanced photoelectrochemical water-oxidation activity

Herein, we report on the variation in photovoltaic (PV) parameters of CdTe/CdS thin-film solar cells fabricated by depositing Cadmium sulfide (CdS) window layers on soda lime, indium doped tin oxide (ITO), fluorine-doped tin oxide (FTO) coated glass substrates by chemical bath deposition (CBD) technique. X-ray diffraction (XRD) patterns confirmed the cubic crystalline structure of the deposited CdS films and the highest diffraction intensity is observed in the film deposited on the FTO substrate. The scanning electron microscopy (SEM) images confirmed the homogenous, crack-free, and smooth nature of the films. The surface roughness values of the CdS films deposited on soda-lime, ITO, and FTO substrates were found to be 35.87, 27.49, and 14.32 nm, respectively. The band-gap values of the CdS films estimated from Tauc's plots are found to be in the range of 2.27–2.33 eV. The strong blue and green bands in PL spectra are found to peak at 560 nm. The peaks observed in the Fourier transform infrared (FT-IR) spectra are corresponding to C-S, Cd-S, and S-C-N vibrations. To fabricate a CdTe/CdS cell, the CdTe layer is deposited on the ITO-CdS and FTO-CdS layers separately. A back contact of silver is pasted on the top layer to complete the solar cell structure and the variations in photovoltaic (PV) parameters were recorded and analyzed. The efficiencies of CdTe/CdS cells fabricated with ITO-CdS and FTO-CdS window layers were found as 8.47% and 9.65%, respectively.

Variations in photovoltaic parameters of CdTe/CdS thin film solar cells by changing the substrate for the deposition of CdS window layer

A comparative study of CdS thin films grown on ultra-thin glass substrates by RF magnetron sputtering and chemical bath deposition

In this work, ITO/CZTS/CdS/Ag and ITO/CdS/CZTS/Ag heterojunction diodes has been produced, CdS and CZTS thin film layers of the diode have been produced on ITO glass at room temperature using PLD technique. It has been produced CZTS thin films that have a polycrystalline structure that were annealed at the sulfurization temperatures of 325 °C, 350 °C and 375 °C when as-grown CZTS thin film has the amorphous structure. CdS thin films have been grown on substrate at room temperature in 15, 20 and 25 min that have polycrystalline structures. Then, CdS thin film deposited for 20 min was annealed at 200 °C temperature and, has better crystal structure compared to other thin films. Diodes have been composed of CZTS thin film annealed in 375 °C, CdS thin film was grown during 20 min and, then annealed at 200 °C temperature. According to J–V characteristics of diode, diodes exhibit some rectification behaviour in dark and show a photo-electric property under illumination conditions. In this article, the ideality factors of diodes in dark condition have been calculated, their electrical parameters of Jsc, Voc, FF and η under the illumination condition have been determined and these electrical properties have been discussed in details.

Determination of electrical parameters of ITO/CZTS/CdS/Ag and ITO/CdS/CZTS/Ag heterojunction diodes in dark and illumination conditions

This chapter focuses on chalcogenides-based nanomaterials such as sulfur, selenium, and tellurium, which is combined with other elements to form binary, ternary, and quaternary materials. In this chapter, fabrication methods of binary, ternary, and quaternary chalcogenides-based nanomaterials were explained. Moreover, their characterization as nanomaterials such as structure, morphology, chemical composition, optical, and electrical properties were described. Also, this review chapter describes elementary information of each chalcogen element, the basic knowledge of chalcogenides nanomaterials and the description of quantum dots on chalcogenides materials as advanced applications.

Advances in chalcogenides and chalcogenides-based nanomaterials such as sulfides, selenides, and tellurides

CdS thin films were deposited on commercial glass substrates by CBD technique at constant temperature and deposition time of 90 °C and 50 min, respectively. The reaction was performed by mixing cadmium acetate, ammonium acetate, ammonium hydroxide, thiourea, and deionized water as an aqueous medium. The S/Cd ratio in the solution was kept constant at 4.46 to make sure that the films were as stoichiometric as possible. Optical, electrical, structural properties and the presence of organic compounds in the films were studied modifying the concentration of ammonium hydroxide (complexing agent) in the bath solution. X-ray diffraction patterns show that all films have the cubic phase with a preferential orientation in the plane (1 1 1). An increase of the film’s resistivity from 102 to 107 Ω-cm is observed by increasing the ammonium hydroxide concentration in the solution in the narrow interval of 0.18–0.36 M. Transmittance values up to 70% are obtained at the lowest concentrations of this reagent, obtaining from these spectra the highest value of the direct bandgap, 2.37 eV. Results about the presence of organic compounds and their influence on the photoluminescence properties are shown, which have not been reported to date. The main organic compound identified by FTIR is cyanamide, whose concentration is higher at the lowest ammonium hydroxide concentrations. Photoluminescence spectra of the films show green, red and orange bands, located at 2.27 eV, 1.78 eV, and 2.02 eV, respectively. An additional band was observed with low intensity at 2.99 eV associated with the presence of nanoparticles in some films. The films with the lower presence of defects, higher uniformity and best optical, electrical and structural properties for their use as window material in solar cells are those deposited from a bath solution with a 0.24 M concentration of the complexing agent.

F.M. Castañeda-de-la-Hoya

Papers

Structural, optical, electrical and morphological properties of CdS films deposited by CBD varying the complexing agent concentration