Hexagonal Cadmium Sulfide Research Articles

Impact of Cobalt-Doping on the Optical, Magnetic, and Electronic Features of Hexagonal Cadmium Sulfide

CdS and Cd0.9Co0.1S samples were prepared under an N2 atmosphere. The structural analysis was conducted using X-ray diffraction. The structural and microstructure parameters were determined using Rietveld refinement method. The incorporation of cobalt ions into CdS matrix was confirmed by energy-dispersive spectroscopy and Fourier-transform infrared analysis. CdS sample has a non-magnetic feature while the Co-doped sample exhibited a magnetic behavior. The origin of magnetic property transformation has been investigated, revealing the emergence of ferromagnetic ordering and the conversion to a diluted magnetic semiconductor (DMS) with a calculated magnetic moment of 2.56 μ B upon Co doping. We also investigated how this Cobalt-doping-driven transformation affected optical, photoluminescence, and electronic properties. These effects correlated with the emergence of hyper-deep defect states. Electronic properties were calculated using density functional theory (DFT) with the HSE06 hybrid functional approximation. The calculated energy bandgaps for both Co-doped and pure CdS were 2.13 and 2.12 eV, respectively, while experimental measurements from our UV analysis yielded values of 2.26 and 2.15 eV. DFT calculations were employed to explore the magnetic properties, absorption coefficients, refractive indices, real and imaginary dielectric components, and energy loss spectra in both samples.

In@CdS sensitized TiO2 nano-rod for enhanced photocatalytic and photoelectrochemical performance under visible light

Titanium dioxide (TiO2) nano-rod are synthesized by one step hydrothermal method while cadmium sulphide (CdS) and Indium (In) doped CdS quantum dots (QDs) are sensitized on the surface of TiO2 nano-rod by using successive ionic layer adsorption and reaction (SILAR) approach. Characterization of this material was done using XRD, XPS, FE-SEM, EDX, HR-TEM, Raman, UV-DRS, PL, EPR. XRD pattern attributed that the preferential orientation of TiO2 grains is along the (101) plane perpendicular to the FTO substrate. XRD pattern also reveals the sensitization of CdS QDs in form of hexagonal CdS QDs and doping of In into CdS QDs. FE-SEM analysis suggests that the TiO2 nano-rod are uniform, thick and grown vertically on the FTO plate. Detailed investigations of the ‘In’ sensitization in 2%In-CdS/TiO2 were carried out by HR-TEM studies. UV-DRS analysis shows decrease in the band gap energy as doping of In in CdS/TiO2 nano-rod increases. EPR analysis reveals the presence of oxygen vacancies due to sensitization of ‘In’ on CdS/TiO2 matrix. The photoelectrochemical and photocatalytic performance of In doped CdS QDs embellished on the surface of TiO2 nano-rod photoanode was investigated by varying the concentration of In. The photo electrochemical (PEC) and photocatalytic H2 generation performance under natural sunlight of as prepared photoanode are explored in terms of photocurrent density and amount of H2 generation. 2% In-CdS/TiO2/Pt/FTO nano-rod shows highest 22.12 ml/h/g of hydrogen generation and photocurrent density of 4.78 (mA/cm2).

One-pot synthesis of a CdS–MoS2 / CNTs nano-composite for photocatalytic hydrogen production under visible light

The need to meet growing energy demands of global society in a sustainable fashion requires the development of techniques and processes to reduce dependence on fossil fuels and transit to renewable energy sources. Environmentally benign technologies for alternative fuel production in the form of hydrogen can be developed via heterogenous photocatalysis, a process based on utilization of solar energy. To this end, a cadmium sulfide (CdS) based photocatalyst was developed, doped with MoS2 in a one-pot solvothermal synthesis technique, and coupled with multi-walled carbon nanotubes (MWCNTs) as a carbonaceous support. The material exhibiting the highest rate of hydrogen evolution, CM5C3, involved a MWCNTs loading of 3% and MoS2 loading of 5%. Compared to pure CdS synthesized with the same adapted procedure, the 3% CNT loading improved the rate of hydrogen production by nearly 7-fold, and the optimal 5% MoS2 loading further improved the performance by 60%. CM5C3, achieved an apparent quantum efficiency of 7.34%, a 26-fold increase compared to pure CdS. FESEM and HRTEM imaging confirmed the nanorod-like growth of CdS–MoS2 on the CNT surface, with elemental mapping confirming homogenous dispersion of MoS2 and CNTs. In addition, lattice fringe spacings indicated the presence of cubic and hexagonal CdS growing predominantly along the (111) and (002) planes respectively, in addition to MoS2 distributed throughout the crystal lattice. XRD analysis confirmed the presence of hexagonal and cubic CdS, however, MoS2 phases were not registered perhaps due to the low concentration present in the bulk of the material. XPS survey scans showed the presence of C, Cd, Mo, and S only, with trace oxygen impurities. Peak deconvolution indicated the presence of characteristic peaks for CdS and MoS2, in addition to evidence of the presence of Cd–C bonds, indicating strong CdS heterojunctions to the CNT surface.

Supernormal enrichment of cadmium in sphalerite via coupled dissolution-reprecipitation process

Supernormal enrichment of cadmium in sphalerite is frequently observed in some sedimentary-hosted zinc-lead deposits, although related fluid process remains unconstrained. At the Jinding Mississippi Valley-type deposit, a considerable portion of cadmium has been remobilized from early sphalerite through coupled dissolution-reprecipitation reaction to form high-grade ores. Here we report natural occurrence of various sulfide nanoparticles and related textures in sphalerite that help document this process. A nanoscale study by transmission electron microscopy provides a rare glimpse of phase transition of cadmium from lattice-bond impurity, composition anomaly along planar defects, aggregates of hexagonal cadmium sulfide nanoparticles, to crystalline greenockite inclusions. Such a process may be mediated by oxidative dissolution on early-formed cadmiferous sphalerite during injection of cadmium-rich oxidative acidic fluids. This study provides an alternative mechanism versus exclusively solid-state diffusion for dispersed elements’ redistribution in hydrothermal ore deposits. It also sheds light on artificial synthesis of II-VI semiconductor nanomaterials by similar methods.

Different look at S-p bonding orbital in CdS, with Zn and Se series gap investigations

The electronic characteristics of Cadmium sulfide (CdS) series Zn x Cd16−x S8Se8 and Cd16Se16−x S x are investigated. According to the calculations, barely 12% Zn (X = 2) in the form Zn2Cd14Se16 is required to maximize the gap. To properly evaluate the excited states, the generalized gradient approximation (GGA) and modified Becke-Johnson (mBJ) potentials are utilized in the computations. The parent compound CdS exhibits three distinct forms of crystal structures, with the hexagonal structure being remarkably stable under the GGA and mBJ functionals. The partial density of states around the Fermi level demonstrates that the system’s electronic characteristics are determined by the interaction of S-p and Cd-s,p states. A substantial splitting of the valence band, shown by band structure analysis, suggests a greater polarization crystal field in the hexagonal CdS structure. The stereochemical activity of the S atom stimulated the CdS compound for extremely tiny displacements of 0.0014 Å and 0.043 Å for the Cd and S atoms in the [001] direction, respectively, as well as tilting of the Cd-S-Cd link. This compound exhibits lone pair properties, with three valance electrons of the p-orbital participating in covalent bonding and S-s electrons fully occupied. Furthermore, Van Hove singularities are discovered in the electron density of states due to the Cd-d atoms that support in the analysis of optical absorption spectra. Finally, the results suggest that CdS has potential for solar cells applications due to its direct wide band gap semiconductor features,

Nanoconfinement dynamics and crystal plane exposure: Synergistic promotion of simulated solar-driven H2O-to-H2 conversion on host (CdS)-guest (Ti single-atom) nano-photocatalyst

Hexagonal cadmium sulfide (h-CdS) is very prospective in photocatalytic hydrogen production due to its appropriate band structure, and researchers concern so much on the morphological characteristics of nanoparticles (NPs) and nanorods (NRs). Due to different dimensions of two forms of nanostructures, very different nanoconfinement (NF) characteristics are presented, leading to different separation and migration kinetics of photoexcitons, thereby showing different catalytic performance. However, the inherent mechanism is still ambiguous, and this NF effect extensively exists in photocatalytic process, even determining the final catalytic performance. Herein, CdS NPs and CdS NRs here were synthesized and decorated by single-atomic titanium (Ti SAs) to construct two forms of nanoconfined systems with host (CdS)-guest (Ti) (H-G) interaction. Due to the typical three-dimensional (3D) NF dynamics of CdS NPs, the H-G interaction of optimized CdS NPs-Ti nanocatalyst played an isotropic synergistic dynamics on body-to-surface (BTS) photoexcitons migration, dramatically suppressing their recombination behaviors, thereby achieving more considerable improvement of simulated sunlight (SSL)-driven HER photoactivity (14.10 mmol·h−1·g−1, 22.5-fold of CdS NPs, AQY400 nm = 20.44%), and outperforming many non-precious metal and precious metal modified CdS nanocatalysts under same experimental conditions. Surface transient photovoltage (TPV) and first-principle calculations revealed that the appropriate crystal plane exposure and typical 3D NF dynamics of CdS NPs highly benefits to the formation of Ti-S bonding interactions followed by the isotropic H-G synergistic dynamics, possessing more boosted BTS migration kinetics of photoexcitons followed by highly suppressed recombination kinetics, thereby acquiring higher solar-to-hydrogen (STH) conversion efficiency. This study provides a prospective insight for elucidating an observable NF dynamics of photoexcitons.

Chemical Deposition of CdxPb1 – xS/CdyS Thin-Film Composite Structures

Thin films of CdxPb1 – xS (0 ≤ x ≤ 0.094) substitutional solid solutions of cubic structure B1 (space group Fm) were prepared by chemical deposition and characterized by X-ray diffraction, scanning electron microscopy, EDX elemental analysis, and Raman spectroscopy. Once the cadmium sulfate concentration in the batch reached some critical value (0.1 mol/L), the films formed involved two autonomous phases: CdxPb1 – xS substitutional solid solutions and hexagonal cadmium sulfide CdyS of structure В4 (space group P63mc). The method and its parameters as proposed are efficient for manufacturing heterostructures in the CdS–PbS system in one-pot deposition.

Host (CdS)-guest (single-atomic Au) electron transfer mechanism for blue-LED-induced atom transfer radical addition of alkenes

Atom transfer radical addition (ATRA) is commonly applied to introduce perfluoroalkyl groups into organic molecules, but it often suffers from harsh reaction condition, poor yield and expensive catalyst usage for practical application. Light-induced ATRA reaction is of great significance due to its merits of mild reaction condition and easy operation, but it is generally difficult to achieve high yield because of the lack of ideal photosensitizers. Herein, an Au single-atom sites (SASs) decorated hexagonal cadmium sulfide (CdS) nanocatalyst (CatCdS-Au) was synthesized to catalyze ATRA reaction under mild blue-LED-induction. As a result, the synergetic effect of CdS-Au interaction enhanced the optical properties and promoted the host (CdS)-guest (Au) electron transfer, leading to high ATRA yields (88–98%) and excellent selectivity even choosing different alkene substrates, which is remarkably superior over existing reaction systems (60–90% yields) ever reported in literatures. The present work sheds light on realizing high ATRA reaction yield via a green and high-efficient synthetic strategy.

A Solvothermal Synthesis of the CdS Nanorods Doped with Cr and Investigation of Ferromagnetic and Optical Properties at Room Temperature

Cr-doped CdS nanorods with room temperature enhanced ferromagnetism have been successfully synthesized by solvothermal reaction. The products were distinctly assigned to the hexagonal phase cadmium sulfide by X-ray diffraction (XRD) measurements. Transmission electron microscopy (TEM) images revealed that the morphologies of CdS doped with different contents chromium were all nanorods. The CdS nanorods morphologies with lengths of 100–350 nm and average diameters of 20–30 nm were almost independent on the quality of introduced chromium. Energy dispersive spectrum (EDS) measurements demonstrated that the synthesized products were consisted of S, Cd and Cr. The vibrating sample magnetometer (VSM) indicated that the Cr-doped CdS nanorods had ferromagnetism at room temperature, while the pure CdS nanorods had weak ferromagnetism. The saturation magnetization Ms of Cr-doped CdS nanorods (Cr = 4.17at%, 7.31at%) was approximately 3.907 and 8.798 (10−3emu/g), respectively. The coercivity of Hc was approximately 96.21, 137.15 Oe. The ferromagnetism of CdS nanorods was associated with Cr substitution in the CdS lattice.

Promoting body carriers migration of CdS nanocatalyst by N-doping for improved hydrogen production under simulated sunlight irradiation

Cadmium sulfide (CdS) has been extensively employed to achieve highly efficient H2 production under visible-light irradiation due to its features of narrow bandgap and appropriate conduction band position. However, fast carriers recombination and severe photocorrosion inevitably result in low carriers utilization, leading to undesirable photocatalytic performance and poor durability. To address the issues, N heteroatoms were introduced into the lattice of hexagonal CdS NPs to prepare the N-doped CdS (N-CdS) nanocatalyst via a wet chemical precipitation coupled with a hydrothermal process. Due to the synergetic promotion of heteroatom-semiconductor coordination (HSC) interaction to body carriers migration of CdS, their recombination behavior was effectively hampered, resulting obviously increased photocurrent density (~2 times) and significantly improved photoexcited carriers utilization. Thereby, high apparent quantum yield (AQY = 32.41%, λ = 500 nm) was achieved by the optimized N0.2-CdS nanocatalyst. Under simulated sunlight (SSL) irradiation, about 3983.4 μmol·h−1·g−1 of HER rate with excellent photostability was achieved at absence of cocatalyst, which raises to about 9-fold greater than that of bare CdS NPs. Moreover, density functional theory (DFT) calculations proved that the energy barrier of water splitting on Cd sites and |ΔGH*| of H2 generation on S sites were reduced obviously due to the synergetic HSC interaction, which thermodynamically accelerated the H2 generation. This study provides a simple and green strategy for gaining highly stable CdS photocatalyst with improved HER photoactivity.

Ultrafast interfacial charge evolution of the Type-II cadmium Sulfide/Molybdenum disulfide heterostructure for photocatalytic hydrogen production

The interfacial charge dynamics was crucial for semiconductor heterostructure photocatalysis. Through the rational design of the heterostructure interface, heterojunction expressed variable recombination and migration dynamics for excited carriers. Herein, followed by a typical chemical bath strategy with the hexagonal cadmium sulfide (CdS) overlapped on the exfoliated molybdenum disulfide (MoS2) film, we developed a cadmium sulfide/molybdenum disulfide (CdS-MoS2) nano-heterojunction and investigated the interfacial charge dynamics for photocatalytic hydrogen evolution. Photoelectron spectroscopy detected an energetic offset between CdS and MoS2, revealing the formation of an interfacial electric field with efficient charges separation. Through transient absorption spectra, we demonstrated the type-II contact at the CdS-MoS2 interface. Driven by the electric field, the excited carriers separated and rapidly migrated to sub-band defects of CdS within the first 500 fs. The carriers-restricted defects provided catalytic active sites, endowing CdS-MoS2 a highly efficient photocatalytic capability. Consequentially, the CdS-MoS2 achieved an enhanced hydrogen evolution rate of 2.3 mmol·g−1·h−1 with significantly stronger photocurrent density. This work gave an insight to the channel of interfacial separation and migration for excited carriers, which could contribute to the interfacial engineering of advanced heterojunction photocatalysts.

Silver doped cadmium sulfide thin films on a PET flexible substrate

Silver doped cadmium sulphide thin films were deposited on a polyethylene terephthalate flexible substrate through the chemical bath deposition method varying the silver deposition time. In this study we analyzed the absorbance in the visible range between 430 and 800 nm. The direct band gap was calculated with the Tauc method, yielding values of 2.25 to 2.46 eV. The crystallographic structure was determined by X-ray diffraction. An evolution was observed from the original hexagonal cadmium sulphide pattern to the appearance of characteristic signals of metallic silver. Scanning electron micrographs were obtained to describe the morphology of the films’s surface. Finally, the electric resistivities measured were in the range of 5.0 and 12.1 x 107 Ω cm.

Pyroelectric effect in CdS nanorods decorated with a molecular Co-catalyst for hydrogen evolution

Abstract Hexagonal cadmium sulfide (CdS) with a noncentro-symmetric structure exhibits piezoelectric and pyroelectric effect due to spontaneous polarization changes companied by temperature variation. However, its pyroelectric effect in pyroelectro-catalytic hydrogen evolution has not been well identified. Herein, we found that CdS nanorods decorated with an organic molecule 2-mercaptobenzimidazole (2MBI) can greatly enhance the pyroelectro-catalytic hydrogen evolution activity. The 2MBI acted as a molecular co-catalyst improves the pyroelectric property of CdS and enhances the separation of pyroelectro-induced charges. Under thermal cycling between 25 °C and 55 °C, CdS-2MBI shows apparently improved pyroelectro-catalytic H2 evolution activity, which is about 5 folds of that for CdS alone. This work may initiate a new prospect for pyroelectric effect in photocatalysis, such as the photocatalytic hydrogen evolution under natural temperature fluctuations.

Photoelectrochemical Investigation on the Cadmium Sulfide (CdS) Thin Films Prepared using Spin Coating Technique

Photoelectrochemical cell technology is one of the simplest technologies, which converts light energy directly into electricity. The synthesis of cadmium sulfide (CdS) nanocrystals (NCs) was performed by the facile hot injection method. The NCs were characterized by different techniques such as XRD, Raman, UV-Vis, FESEM, and XPS. The XRD pattern confirms the phase pure hexagonal CdS NCs. The band gap of NCs calculated from the UV-Visible spectrum is at 2.40 eV, indicating good absorption in the visible spectrum. XPS analysis confirmed the presence of individual elements in CdS NCs. The CdS thin-films having different thicknesses were prepared on FTO substrates using the spin coating technique. Photoelectrochemical (PEC) investigation of CdS NCs thin-films photoelectrodes was performed by varying its thickness. The increase in the thickness of thin-films increased photocurrent density.

Promoting charge carriers transfer of Co–S bonds in Co/CdS for enhanced photocatalytic CO<sub>2</sub> reduction

Converting greenhouse gas of carbon dioxide (CO2) into hydrocarbon fuels using solar energy has been generally considered to be possible to solve the ever-growing energy crisis and environmental pollution, simultaneously. As one promising method, photocatalytic CO2 reduction into useful chemicals is receiving considerable attention around the world. However, the efficiency of photocatalytic CO2 reduction is far beyond satisfactory due to the low catalytic performance and poor stability. In general, the whole photocatalytic CO2 reduction process involves three steps to achieve: (1) Generation of electron-hole pairs resulting from light absorption of a semiconductor, (2) separation and transfer of photoexcited electron-hole pairs to the surface of the semiconductor, and (3) surface reactions of CO2 with H2O. The kinetic process of charge separation/transfer and surface reactions involved in the second and third steps are believed to be the two key steps to limit the efficiency of photocatalytic CO2 reduction. As one of the promising photocatalysts for CO2 reduction, cadmium sulfide (CdS) has attracted extensive attention due to its relatively suitable bandgap (2.4 eV) to utilize visible light and sufficiently negative potential of the conduction band edge to reduce CO2 to other carbon sources. However, the photocatalytic activity of pure CdS for CO2 reduction is very low due to the fast charge carrier recombination as well as photocorrosion during the photocatalytic process. Both disadvantages of CdS can be overcome after introducing noble metal cocatalysts onto CdS, which can not only realize the suppressing of charge carrier recombination but also afford reaction active sites for proton-reduction, and finally boost photocatalytic efficiency for CO2 activation. Nevertheless, the scarcity and high costs of noble metals inspired the researchers to explore earth abundant metals as alternative cocatalysts. The recent investigation showed that cobalt metal (Co) has loosely bonded d-electrons as high electrical conductivity. More importantly, partial oxidation of Co to CoO x can improve the CO2 adsorption capacity. Because of these merits, Co is expected to be a suitable cocatalyst for photocatalytic CO2 reduction. In this work, highly dispersed Co/CdS photocatalyst was synthesized via a two-step method. Firstly, the hexagonal phase CdS was prepared by a hydrothermal method. The Co metal was deposited on the surface of CdS using NaBH4 as the reductant. The results of energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) suggested that highly dispersed Co2+ was anchored on CdS surface to form Co–S bond. Combined with the photoluminescence (PL), transient photocurrent ( I-t ) and electrochemical impedance spectroscopy (EIS) analysis, the Co–S bonds acted as charge transfer channels were revealed to effectively enhance the separation and migration of photogenerated carriers from Co/CdS. Theoretical calculation using DFT demonstrated that the introducing Co onto CdS improved the adsorption ability of CO2 and CO, and promoted the formation of CH4, achieving 64.9% selectivity toward CH4 evolution. As a result, the formation rates of CO (3.23 μmol g–1 h–1) and CH4 (1.86 μmol g–1 h–1) were 2.5 and 7.5 folds higher than that of bare CdS, respectively. In addition, the photocatalytic activity remained CO (3.07 μmol g–1 h–1) and CH4(2.01 μmol g–1 h–1) after 5 recycle tests. Therefore, this work provides an attractive strategy for designing efficient and stable CdS photocatalyst for CO2 reduction.

A comprehensive study of opto-electrical and nonlinear properties of Cu@CdS thin films for optoelectronics

Good quality cadmium sulfide (CdS) thin films were deposited on substrates of glass with different Cu concentrations using a sophisticated spray pyrolysis technique. Structural study confirms the formation of hexagonal phase CdS films with good crystallinity. The crystallite size was calculated to be in range from 19 to 21 nm and the texture coefficient was found to be higher along (110) plane for 1.0 wt.% CdS:Cu film. Further confirmation of hexagonal phase with improved crystallinity was approved by vibrational spectroscopy analysis. SEM mapping/EDX spectra shows the homogeneous presence of Cu in final film. SEM signify the nanostructured thin films fabrication with nanocrystallites formations. The optical transparency of fabricated films was noticed in range of 60 to 80%. The absorption and refractive indices values were estimated and found in range of 0.03 to 0.24, 1 to 3. The direct energy gap was noticed to reduce from 2.44 to 2. 31 eV by Cu doping. The PL spectra contains a single peak in range from 502 to 532 nm for pure and Cu doped CdS films, which is assigned to green emission and noted to be shifted towards lower wavelength. Dielectric constant, loss. loss tangent and conductivity were also determined and discussed. Moreover, the third order nonlinear susceptibility and nonlinear refractive index were calculated and found to be of high orders. The optical limiting study was also carried and shows noticeable effect of Cu doping. All results suggest that the CdS:Cu films are of good quality hence can be employed in opto-nonlinear devices.

Preparation of carbon-supported CdS photocatalysts with high performance of dye photodegradation using cadmium-enriched Perilla frutescens biomass

Cadmium sulfide (CdS), which is a typical and important semiconductor, has become enormous research concern in photocatalysis for environmental remediation. However, the practical usage of CdS in photocatalysis was largely limited because of photocorrosion, and the toxic Cd2+ ions would be released which leading to the potential environmental risks. To improve this defect, specific research has been focusing on fabrication of stable CdS nanocomposites by supporting with carbon-based materials. In this study, cadmium-enriched Perilla frutescens root was selected to in situ fabricate carbon-supported CdS nanocomposite photocatalyst. It was found that the CdS@CP contained CdS nanoparticles which were indexed to mixed-phase cubic and hexagonal CdS. Estimated band gap energy of CdS@CP (2.21 eV) was obviously lower than the pure CdS (2.57 eV), which implying that the new synthesis of CdS@CP was more easily to be motivated by visible light and required less energy compared with pure CdS. Moreover, the photodegradation rate of Rhodamine B (RhB) by CdS@CP was ca. 98%, and it exhibited high catalytic performance and durability in photodegradation of dye. The synthesis of CdS@CP photocatalysts with high performance of dye photodegradation would be a facile and low-cost pathway for achieving high value utilization of Cd-enrich biomass.

An Effective of Dye Molecules with Cadmium Sulfide Nanorods in Dye Sensitized Solar Cell (DSSCs)

The aligned hexagonal cadmium sulfide nanorods (CdSNR) have been synthe-sized by hydrothermal technique at 200&#186C on fluorine tin oxide (FTO) sub-strates. Dye sensitized solar cells (DSSCs) based on the photoelectrode core-shell CdSNR array with conductive polymers nanocomposite of polyaniline (PANI) and poly(3,4-ethylenedioxyl-thiophene)/poly(styrene-sulfonate) (PEDOT:PSS) were fabricated and designed with different types of dye molecules. DSSCs were characterized utilizing scanning electron microscopy (SEM), Raman scattering, energy dispersive spectroscopy (EDS), UV-Vis absorption spectroscopy, X-ray diffraction (XRD), and photocurrent-voltage (J-V) characteristic. Results show that under illumination (AM 1.5 G), the high power conversion energy (PCE) was achieved for CdSNR/PANI-PEDOT:PSS device when it sensitized with ruthenium (II) (dye N-719) of 0.91% and a short circuit current density (Jsc) of 4.21 mA/cm2 in comparison with the other devices, which sensitized with natural dyes. The high performance of the CdSNR/PANI-PEDOT:PSS-N719 device attributed to the wide range of absorption and photostability for N719. This work shows that the CdSNR with N719 can be appropriate candidate for photovoltaics device for their low cost fabrication procedure and excellent absorption.

XRD, OPTICAL AND VIBRATIONAL PROPERTIES OF ANNEALED CADMIUM SULFIDE FILMS

Cadmium sulfide (CdS) films have been formed using an ultrasonic spray pyrolysis method. These films annealed at a temperature range of 200-500oC in air for 5 hours. The effects of annealing on the vibrational, structural, optical and morphological properties of cadmium sulfide films were looked at using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, UV-visible spectroscopy(UV–vis) and atomic force microscopy (AFM). The X-ray diffraction data showed that the films had settled along (100) direction with a hexagonal wurtzite type structure. It was found that grain size goes up with an increase in the annealing temperature. The optical band gap numbers of the CdS film at different annealing temperatures were calculated and were found to be in the range of 2.40-2.44 eV. Raman results showed two rises attributed to the 1LO (300cm-1) and 2LO (601cm-1) modes of hexagonal CdS. The chemical bonding was studied by FTIR spectra. The saturation rises in the FTIR spectra of the films located at 550–715 and 844–1160 cm-1 can be given to the Cd–S and C–O phonon modes, respectively. The AFM of all the films were determined. These images colors changed with the annealing temperature.

A facile route for synthesis of cadmium sulfide thin films

This study describes a facile spin-coating deposition technique for cadmium sulfide thin film. The structural analysis revealed the formation of a pure hexagonal cadmium sulfide phase. The lattice constant, the crystallite size, dislocation density and micro strain were calculated. Energy dispersive x-ray analysis confirmed that these as-prepared CdS thin films are stoichiometric. The surface morphology studies showed homogenous and uniform films without any cracks with a low surface roughness of value 9 nm. The optical analysis indicated a relatively high transmission, optical band gap of 2.4 eV and Urbach energy value of 0.48 eV. All these properties indicate that cadmium sulfide thin films prepared by this simple route can be used as a window in heterojunction photovoltaic solar cells.