International Conference on Recent Advancements in Materials (ICRAM) 2015 Synthesis and dielectric properties of CdO nanoparticles for the fabrication of dye sensitized solar cell (original) (raw)
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An effective use of nanocrystalline CdO thin films in dye-sensitized solar cells
Solar Energy, 2006
Thin films of cadmium oxide (CdO) were synthesized by layer-by-layer deposition method on indium doped tin oxide (ITO) substrates. Post-deposition annealing at 250°C for 24 h produced pure phase CdO films by removal of trace amount of cadmium hydroxide, as confirmed from X-ray diffractogram. First time employment of CdO in place of TiO 2 in dyesensitized solar cells is reported to check feasibility and cell performance. A dye-sensitized nanocrystalline CdO photo-electrode was obtained by adsorbing cis-dithiocyanato (4,4 0 -dicarboxylic acid-2,2 0 -bipyridide) ruthenium (II) (N3) dye by keeping at 45°C for 20 h. The efficiency of dye-sensitized nanocrystalline CdO thin film solar cell was increased from 0.24% to 2.95% due to dye adsorption. This must be highest reported conversion efficiency for other metal oxides than TiO 2 based dye-sensitized solar cells.
Cadmium sulfide nanoparticles were prepared by chemical precipitation method in aqueous medium using cadmium acetate and sodium sulfide. The synthesized nanoparticles were characterized by using UV-Vis studies, X-ray diffraction studies (XRD), field emission scanning electron microscopy (FESEM), energy dispersive x-ray analysis (EDAX) and BET analysis. The X-ray diffraction pattern revealed that the synthesized cadmium sulfide nanoparticles were polycrystalline nature and grain size 7 nm was calculated by using Scherer method. Specific surface area, pore volume and pore size were estimated by nitrogen adsorption-desorption analysis. The specific surface area of the synthesized material is 74.26 m 2 /g. The temperature and frequency dependence of dielectric constant, dielectric loss and AC conductivities were studied over a range of frequency (50 Hz to 5 MHz) and temperature (40-200°C). These results demonstrate that the CdS nanoparticles has a potential applications in DSSC's.
Fabrication and Characterization of Zn-doped CdTe nanoparticles based Dye sensitized solar cells
In the present work, undoped and Zn-doped CdTe nanoparticles are grown by chemical reduction method. The grown synthesized nanoparticles are characterized structurally by X-Ray diffraction (XRD) and transmission electron microscopy (TEM). The X-ray diffraction study confirmed the crystal structure of undoped and Zn-doped CdTe nanoparticles. Transmission electron microscopy study indicates the nature and size of the nanoparticles. The grown nanoparticles are characterized optically by Optical Absorption, Photoluminescence (PL) studies. The optical properties of the dye are also studied. The extraction of Hibiscus mutabilis is used as a natural dye. Also photoconductivity study shows the change of photosensitivity and relaxation time with doping. Dye sensitized solar cells based on doped as well as undoped CdTe have been fabricated and characterized through J-V study at dark and under illumination of light condition. The measurement of efficiency and fill factor, open circuit voltage and short circuit current density of the dye sensitized solar device are also carried out.
Electrochimica Acta, 2014
Electrophoresis deposition (EPD) was used for fabrication of TiO 2 layer on the FTO glass substrate. Different chemical methods such as successive ion layer adsorption and reaction (SILAR), chemical bath deposition (CBD), microwave (MW) and hydrothermal (HT) were served to deposition of CdS on the prepared TiO 2 surface. Also TiO 2 /CdS nanocomposite was synthesized by hydrothermal method and was then deposited on the FTO surface via doctor balde (DB) technique. The effect of deposition method on optical properties was investigated. The results showed that different deposition methods create different electrodes with various optical properties. The surfaces was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), cross-section SEM, UV-Vis diffuse reflectance spectroscopy (DRS), energy dispersive X-ray analysis (EDX) spectroscopy, atomic force microscopy (AFM), cyclic voltammetry (CV) and UV-vis spectroscopy. Dye-sensitized solar cells (DSSC) made by the fabricated electrodes as working electrode and then investigated by current density-voltage (J-V) curve and electrochemical impedance spectroscopic (EIS). It was found that deposition method has significant role in solar cell performance and efficiency.
International Journal of ChemTech Research
Cadmium selenide (CdSe), Cu and Mn-CdSe nanoparticles were synthesized by solvothermal method using polyethylene glycol as a capping agent. The structures, elements, shape and spectral properties of these nanocrystals are investigated. The obtained Cu-CdSe and Mn-CdSe nanocrystal are consistent with the hexagonal wurtzite crystal structure and the crystallite sizes were found to be 13.70 nm, 8.05 nm, and 6.3 nm respectively. The band gap energy was computed from the absorption data as 1.7 eV for CdSe nanoparticles, 2.7 eV and 3.9 eV for Cu and Mn-CdSe nanoparticles respectively. Scanning electron microscope (SEM) illustrated that the dopants adhered to the substrate uniformly and the effective doping was further confirmed by EDX spectral analysis. The solar cell was fabricated using TiO 2 as photoanode, CdSe and Cu, Mn-CdSe as a counter electrode, ruthenium dye as sensitizer and I-/I 3 as electrolyte and the maximum conversion efficiency of solar cells were found to be 3.57 % for CdSe, 4.16 % for Cu-CdSe and 5.52 % for Mn-CdSe nanoparticles.
Fabrication of CdS nanorods and nanoparticles with PANI for (DSSCs) dye-sensitized solar cells
Solar Energy, 2017
A thin film and core-shell dye-sensitized solar cell containing cadmium sulfide (CdS) are fabricated by using low cost solution processes. CdS nanoparticles (NPs) and nanorods (NRs) are embedded within the dye-sensitized solar cells structures and investigated. The morphology of CdS NPs and CdS NRs were controlled and characterized with multiple techniques including scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Raman scattering, and optical absorption. The inclusion of CdS thin film in zinc oxide/polyaniline (ZnO/PANI) hybrid solar cells increases the energy conversion efficiency from 0.125% to 1.35%. The energy conversion efficiency of the core-shell devices was found higher than that of the corresponding planar structures fabricated under similar conditions. By increasing the crystallinity and absorption, the energy conversion efficiency of the CdS NRs device was increased to 2.44%.
Cadmium sulfide nanoparticles were prepared by chemical coprecipitation method using cadmium acetate and, sodium sulfide usingand tetrabutylammonium bromide (TBAB) as a capping agent. The synthesized nanoparticles were characterized by using UVVis spectroscopic analysis, Xray diffraction analysis (XRD), Field emission scanning electron microscopic analysis (FESEM), Energy dispersive Xray analysis (EDAX) and BET surface area nitrogen adsorptiondesorption analysis. The band gap of capped CdS was calculated by using UVVis absorption spectrum as 3.23 eV. The Xray diffraction pattern revealed that the synthesized cadmium sulfide nanoparticles were polycrystalline nature with wurtzite hexagonal structure and crystallite size was calculated as 7.2 nm by using Debye Scherer method. The surface area, pore volume and pore size were found to be 93.15 m /g, 1.64 × 10 cm /g and 6.2 Å by BET nitrogen adsorptiondesorption analysis. The dielectric constant, dielectric loss and AC conductivities were studied over a range of frequency (50 Hz– 5 MHz) and temperature (40–200 °C). Solar cell was fabricated using cadmium sulfide as photocathode material, titanium dioxide as photoanode material, potassium iodide/iodine as an electrolyte solution, ruthenium dye as a sensitizer and power conversion efficiency was found to be 2.7 %.
Synthesis and characterization of CdO nano particles by the sol-gel method
Cadmium oxide (CdO) nanoparticles were prepared starting from organometallic cis-[dmphen-CdI 2 ] complex (dmphen = 2,9-Dimethyl-1,10-phenanthroline) through one step calcination process at 800 o C, the thermal behavior of the complex during calcination was recorded by TGA/DTA. The obtained product are analyzed by FT-IR, UV-visible, X-ray diffractometer (XRD), EDS, SEM and TEM, the average size of CdO nanoparticles found to be 50 nm.
The mild and simple solution method was used for the synthesis of Co 2+-and Ni 2+-doped CdO powders at room temperature. The prepared powders were characterized using powder X-ray diffraction, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), optical absorption, and Fourier transform infrared spectroscopy (FTIR). From the powder X-ray diffraction patterns, it has been observed that the prepared Co 2+ and Ni 2+ ion-doped CdO powders belong to the cubic phase, and the evaluated average crystalline sizes of the powders are 20 and 14 nm, respectively. The SEM images and the EDS spectra show that the prepared powders are distributed over different sizes in the grain boundaries. Optical absorption studies allow determination of site symmetry of the metal ion with its ligands. The crystal fi eld (Dq) and inter-electronic repulsion (B and C) parameters have been evaluated from the optical absorption spectra. The FTIR spectra show the characteristic fundamental vibrations of the metal oxide and CdO. Introduction. Cadmium oxide (CdO) is a semiconductor with a band gap of 2.4 eV. It has excellent electrical, mechanical, and optical properties. It has a cubic crystal structure of high density (8150 kg/m 3) and melting point (1500 o C) with alternating Cd and O atoms located at lattice points. CdO is an n-type semiconductor and has been widely investigated owing to its potential applications in optical fi elds, photovoltaic cells, and transparent electrodes [1, 2]. So far a number of methods have been used to synthesize various nanostructures, including thermal evaporation [3, 4], chemical bath deposition [5], solvothermal synthesis [6] and plasma-assisted approach [7–9]. The opto-electrical properties of CdO could be controlled by doping with different metallic ions such as In, Sn, Al, Sc, Y, Tl, Fe, Sm, Dy, etc. [10–17]. It has been observed that doping with ions of a radius smaller than that for Cd 2+ results in an increase in the doped material conductivity. The addition of ions with ionic radii equal or larger than Cd 2+ does not sig-nifi cantly alter the lattice parameters. By introducing a magnetic element into a non-magnetic matrix, some special physical properties, such as the giant magneto-resistance effect and mixed magnetism, can appear because of the change in magnetism, structure, and electrical transport [18]. Zou et al. [19] have prepared CdO nanoparticles by the micro-emulsion method employing AOT reverse micelles. There is also a report of stearate-coated CdO nanoparticles of 5–10 nm size range, obtained by the micro-emulsion method starting from an aqueous solution of cadmium salt and stearic acid in xylene [20]. A new method to prepare CdO nanoparti-cles has been reported, wherein a cadmium precursor compound is decomposed under solvothermal [21, 22] conditions in the presence of a capping agent. For this purpose, the cadmium compound Cd(C 6 H 5 N 2 O 2) 2 was used as the precursor and CdO nanoparticles of different sizes were obtained using tri-n-octylphosphine oxide (TOPO) as the capping agent [23]. Among these methods, the mild and simple solution method is rather effective in realizing the diversifi ed forms of CdO nanostructures using aqueous and non-aqueous solutions. The advantage of this method compared with other mentioned techniques includes low process temperature, inexpensiveness, and the capability of controlling the morphology of metal oxide semiconductors.