scholarly journals Growth evolution and phase transition from chalcocite to digenite in nanocrystalline copper sulfide: Morphological, optical and electrical properties

2014 ◽  
Vol 5 ◽  
pp. 1542-1552 ◽  
Author(s):  
Priscilla Vasthi Quintana-Ramirez ◽  
Ma Concepción Arenas-Arrocena ◽  
José Santos-Cruz ◽  
Marina Vega-González ◽  
Omar Martínez-Alvarez ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Electrical Properties ◽  
Band Gap ◽  
Copper Sulfide ◽  
Amorphous Structure ◽  
Band Gap Energy ◽  
Morphological Properties ◽  
One Pot ◽  
Nanocrystalline Copper ◽  
Lower Energy Band

Copper sulfide is a promising p-type inorganic semiconductor for optoelectronic devices such as solar cells, due its small band gap energy and its electrical properties. In this work nanocrystalline copper sulfide (Cu x S), with two stoichiometric ratios (x = 2, 1.8) was obtained by one-pot synthesis at 220, 230, 240 and 260 °C in an organic solvent and amorphous Cu x S was obtained in aqueous solution. Nanoparticle-like nucleation centers are formed at lower temperatures (220 °C), mixtures of morphologies (nanorods, nanodisks and nanoprisms) are seen at 230 and 240 °C, in which the nanodisks are predominant, while big hexagonal/prismatic crystals are obtained at 260 °C according to TEM results. A mixture of chalcocite and digenite phases was found at 230 and 240 °C, while a clear transition to a pure digenite phase was seen at 260 °C. The evolution of morphology and transition of phases is consistent to the electrical, optical, and morphological properties of the copper sulfide. In fact, digenite Cu1.8S is less resistive (346 Ω/sq) and has a lower energy band gap (1.6 eV) than chalcocite Cu2S (5.72 × 105 Ω/sq, 1.87 eV). Low resistivity was also obtained in Cu x S synthesized in aqueous solution, despite its amorphous structure. All Cu x S products could be promising for optoelectronic applications.

scholarly journals One-Pot Synthesis of Ru-Doped ZnO Oxides for Photodegradation of 4-Chlorophenol

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Maria E. Manríquez ◽  
Luis Enrique Noreña ◽  
Jin An Wang ◽  
Lifang Chen ◽  
Jose Salmones ◽  
...  
Keyword(s):  
Band Gap ◽  
Mixed Oxides ◽  
Active Surface ◽  
Band Gap Energy ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
One Pot ◽  
Notable Increase ◽  
Doped Zno ◽  
The One

The photocatalytic degradation of 4-chlorophenol in water using Ru-doped ZnO mixed oxides (0, 0.5, 1, and 3 wt% RuO2) synthesized by the one-pot homogeneous coprecipitation method is reported. ZnO with wurtzite structure was present in the mixed oxide as corroborated by Raman spectroscopy and X-ray diffraction analysis. All the samples showed nanorod morphological features. The presence of Ru6+/Ru4+ couples on ZnO modified the band gap of the mixed oxides and led to a shift of the band gap energy from 3.20 eV to 3.07 eV. Ru addition increased the surface area and significantly promoted the formation of active surface oxygen species such as hydroradicals evidenced by the fluorescence spectroscopy measurement. In the photodegradation of 4-chlorophenol solution under UV irradiation, a notable increase in photoactivity was obtained as the amount of RuO2 in the mixed oxides increased to 3 wt%. The charge transfer between Ru6+/Ru4+ couples and ZnO nanoparticles together with the formation of free radical oxidant species effectively inhibits electron-hole recombination rate, thus favoring the photodegradation of 4-chlorophenol.

scholarly journals Processing and Study of Optical and Electrical Properties of (Mg, Al) Co-Doped ZnO Thin Films Prepared by RF Magnetron Sputtering for Photovoltaic Application

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2146 ◽  
Author(s):  
Chayma Abed ◽  
Susana Fernández ◽  
Selma Aouida ◽  
Habib Elhouichet ◽  
Fernando Priego ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Magnetron Sputtering ◽  
Band Gap ◽  
Rf Magnetron Sputtering ◽  
Band Gap Energy ◽  
Thin Layers ◽  
Working Pressure ◽  
Hall Effect Measurements ◽  
Diffraction Patterns

In this study, high transparent thin films were prepared by radio frequency (RF) magnetron sputtering from a conventional solid state target based on ZnO:MgO:Al2O3 (10:2 wt %) material. The films were deposited on glass and silicon substrates at the different working pressures of 0.21, 0.61, 0.83 and 1 Pa, 300 °C and 250 W of power. X-ray diffraction patterns (XRD), atomic force microscopy (AFM), UV-vis absorption and Hall effect measurements were used to evaluate the structural, optical, morphological and electrical properties of thin films as a function of the working pressure. The optical properties of the films, such as the refractive index, the extinction coefficient and the band gap energy were systematically studied. The optical band gap of thin films was estimated from the calculated absorption coefficient. That parameter, ranged from 3.921 to 3.655 eV, was hardly influenced by the working pressure. On the other hand, the lowest resistivity of 8.8 × 10−2 Ω cm−1 was achieved by the sample deposited at the lowest working pressure of 0.21 Pa. This film exhibited the best optoelectronic properties. All these data revealed that the prepared thin layers would offer a good capability to be used in photovoltaic applications.

scholarly journals Investigating the Photoelectrochemical Performance of WO3-TiO2 Nanorod Photoanodes in Water Splitting

2021 ◽  
Author(s):  
Armin Hariri ◽  
Neda Gilani ◽  
Javad Vahabzadeh Pasikhani
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Hydrogen Generation ◽  
Band Gap Energy ◽  
Pure Tio2 ◽  
High Rate ◽  
Photoelectrochemical Performance ◽  
One Pot ◽  
Gap Energy ◽  
Tio2 Nanorod

TiO2 nanorod as a superior nanostructure has attracted a lot of attention to exert in the photocatalytic and photoelectrocatlytic applications in recent years. Nevertheless, its practical usage is restricted by a number of limitations such as the large band gap energy, the low rate of photo-induced carriers generation and the high rate of charge carriers recombination. Therefore in this study, incorporation of TiO2 nanorod with WO3 is proposed as a suitable approach to overcome these defects. In this regard, WO3-TiO2 nanorod was constructed by a facile one pot hydrothermal method in two incessant steps and was then employed as a potent photoanode for photoelectrocatalytic hydrogen generation. The morphology, elemental compositions and optical properties were characterized by the FESEM, EDS and DRS analysis, respectively. Furthermore, voltammetry analyses were performed to assay the photoelectrochemical features of WO3-TiO2 nanorod. The results confirmed that the incorporation of TiO2 nanorod with WO3 not only significantly made the band gap energy narrower (from 3eV to 2eV), but also dramatically intensified the photocurrent density and photoconversion efficiency from 1mA.cm-2 to 1.8mA.cm-2 and from 0.3% to 0.45%, respectively. As a consequence of improving optical properties and photoelectrochemical features, WO3-TiO2 nanorod could generate 2.43 mmol H2 during 100 min under UV irradiation, which was 1.71 times more than hydrogen generated over pure TiO2 nanorod

Structural, optical and electrical properties of transparent conducting CuInO2 thin films prepared by RF sputtering

2005 ◽  
Vol 865 ◽  
Author(s):  
Bin Yang ◽  
Yunbin He ◽  
Angalika Polity ◽  
Bruno K. Meyer
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Electrical Properties ◽  
Band Gap ◽  
Rf Sputtering ◽  
Wavelength Dependence ◽  
Band Gap Energy ◽  
Optical And Electrical Properties ◽  
Transparent Conducting ◽  
Delafossite Structure

AbstractThe transparent conducting CuInO2 thin films were prepared by radio frequency (RF) reactive sputtering and post growth annealing. A study of structural, optical, and electrical properties was performed on the films. The crystalline phase in the films was identified to be the delafossite structure. The optical properties, such as the wavelength dependence of the transmittance and the band gap energy, were determined. The average transmittance is 70% in the wavelength range of 400-1100 nm and the band gap is ˜3.7 eV. The temperaturedependence of electrical conductivity in the CuInO2 delafossite thin films was measured from 70 to 400K. The resistivity, carrier density, and mobility of the thin films at 300K were 1.8x101 Δcm, 1.6x1019 cm-3 and 2x10-1 cm2/Vs, respectively. Hall coefficient indicated that the CuInO2 thin films are n-type conductors. The electrical conductivity showed semiconducting type at room temperature.

Colloidal copper sulfide nanocrystals: Electrochemical, electrical and morphological properties

2015 ◽  
Vol 1748 ◽  
Author(s):  
Alejandro Baray-Calderón ◽  
R. Galindo ◽  
J. L Maldonado. ◽  
Omar Martínez-Alvarez ◽  
L.S. Acosta-Torres ◽  
...  
Keyword(s):  
Copper Sulfide ◽  
Colloidal Solution ◽  
Argon Atmosphere ◽  
Morphological Properties ◽  
One Pot ◽  
Three Samples ◽  
Absorbing Material ◽  
Homo And Lumo ◽  
Homo Lumo ◽  
Sulfide Nanocrystals

ABSTRACTThe highlight of this work is the synthesis of copper sulfide nanocrystals by a simple one-pot colloidal process, and the study of its electrochemical, electrical and morphological properties. Nanocrystals of Cu1.8S of about 15-30 nm were obtained at a temperature of 240°C under an argon atmosphere. The colloidal solution of the nanocrystals was analyzed by cyclic voltammetry. Agreeing to the values of EOx and ERedvs. SCE, and the average of three samples the HOMO and LUMO levels are 6.16 and 4.27 eV, respectively, the calculated HOMO – LUMO (Eg) is 1.89 eV. The Eg value, differs of that value obtained from Kubelka-Munk equation (1.7 eV). The photocurrent vs. time results showed that the Cu1.8S/Cu junction is photosensitive and could be used as absorbing material. The morphology and the topography of the film were analyzed by SEM and AFM techniques. Irregular agglomeration of nanocrystals was observed and a roughness of about 194 nm.

scholarly journals Photoelectrochemical investigations of thermally formed films on titanium surfaces

2009 ◽  
Vol 28 (2) ◽  
pp. 181
Author(s):  
Irena Mickova
Keyword(s):  
Thermal Treatment ◽  
Band Gap ◽  
Amorphous Structure ◽  
Band Gap Energy ◽  
Theoretical Background ◽  
Thermal Treatments ◽  
Tio2 Films ◽  
Rutile Structure ◽  
Photoelectrical Properties ◽  
Titanium Surfaces

The semi-conducting and photoelectrical properties of TiO2 films prepared with thermal oxidation of titanium in the temperature range from 200 to 600 ºC were studied. Short theoretical background for application of photocurrent in semiconductor electrochemistry was presented. For all investigated temperatures and times of thermal treatments the semi-conducting properties as photocurrent peaks and band gap energies were determined. At lower temperatures the anodic values of photocurrent peaks confirmed the existence of n-type semiconducting TiO2 films with amorphous structure. With increasing the temperature and time of thermal treatment the development of crystalline structure in the film is followed with small decreasing of band gap energy. For films formed at higher temperatures and longer time of thermal treatment the determined band gap energies are close to the 3 eV that corresponds to the rutile structure of the film.

scholarly journals Study of the Optical, Electrical, Structural and Morphological Properties of Electrodeposited Lead Manganese Sulphide (PbMnS) Thin Film Semiconductors for Possible Device Applications

2021 ◽  
Vol 8 (1) ◽  
pp. 40-51
Author(s):  
Augustine Nwode Nwori ◽  
Nnaedozie Laz Ezenwaka ◽  
Ifenyinwa Euphemia Ottih ◽  
Ngozi, Agatha Okereke ◽  
Nonso Livinus Okoli
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Light Emitting Diode ◽  
Xrd Analysis ◽  
Band Gap Energy ◽  
Morphological Properties ◽  
Conductive Glass ◽  
Device Applications ◽  
High Absorption Coefficient ◽  
Range Of Values

Semiconductor thin films of lead manganese sulphide (PbMnS) have been successfully deposited on florinated tin oxide (FTO) conductive glass substrate using an electrodeposition method. Lead acetate (Pb(CH3COO)2), manganese sulphate (MnSO4.H2O) and thiourea (CH4N2S) were the precursor used for cadmium (Cd2+), manganese (Mn2+) and sulphur (S2-) sources respectively. The concentration of manganese (Mn2+) was varied while keeping the concentrations of Pb2+ and S2- constant at 0.2 M and 0.1 M respectively. The deposited films were annealed at temperature of 250 oC and subjected for optical, electrical, structural and morphological characterizations. The results of the characterizations showed that the deposited thin films of PbMnS have high absorbance, high absorption coefficient throughout VIS and NIR regions. The band gap energy of the films is tuned to the order of 1.9 eV to 2.0 eV and tends to constant as concentration of Mn2+ increased. The electrical properties (electrical resistivity and conductivity) of the films are dependent on the concentration of Mn2+ and film thickness. The range of values of the electrical properties is found to be within the range of values for semiconductor materials. The XRD analysis revealed that the deposited thin films of PbMnS is crystalline but the crystallinity declined with increase in concentration of Mn2+. The SEM morphology showed that the surfaces of the films are highly homogeneous in nature and particle sizes are uniform on the substrate with the majority of the particles been spherical in shape. These observed properties exhibited by the deposited thin films of PbMnS make the films good materials for many optoelectronic and electronic applications such as solar cell, light emitting diode (LED), photodetector etc.

Hybridization of zirconia, zinc and iron supported on HY zeolite as a solar-based catalyst for the rapid decolorization of various dyes

2015 ◽  
Vol 39 (6) ◽  
pp. 4526-4533 ◽  
Author(s):  
Norzahir Sapawe
Keyword(s):  
Band Gap ◽  
Band Gap Energy ◽  
Good Stability ◽  
One Pot ◽  
Hy Zeolite ◽  
Gap Energy ◽  
Lower Band ◽  
Nanocomposite Catalyst

A Zr/Zn/Fe/HY nanocomposite catalyst with high photoactivity, good stability and a lower band gap energy was generated via a one-pot electrosynthesis.

Modification of optical properties of PC-PBT/Cr2O3 and PC-PBT/CdS nanocomposites by gamma irradiation

2020 ◽  
Vol 92 (2) ◽  
pp. 20402
Author(s):  
Kaoutar Benthami ◽  
Mai ME. Barakat ◽  
Samir A. Nouh
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Color Difference ◽  
Band Gap Energy ◽  
Polybutylene Terephthalate ◽  
Γ Irradiation ◽  
Gap Energy ◽  
Vis Spectroscopy ◽  
Oxygen Atoms

Nanocomposite (NCP) films of polycarbonate-polybutylene terephthalate (PC-PBT) blend as a host material to Cr2O3 and CdS nanoparticles (NPs) were fabricated by both thermolysis and casting techniques. Samples from the PC-PBT/Cr2O3 and PC-PBT/CdS NCPs were irradiated using different doses (20–110 kGy) of γ radiation. The induced modifications in the optical properties of the γ irradiated NCPs have been studied as a function of γ dose using UV Vis spectroscopy and CIE color difference method. Optical dielectric loss and Tauc's model were used to estimate the optical band gaps of the NCP films and to identify the types of electronic transition. The value of optical band gap energy of PC-PBT/Cr2O3 NCP was reduced from 3.23 to 3.06 upon γ irradiation up to 110 kGy, while it decreased from 4.26 to 4.14 eV for PC-PBT/CdS NCP, indicating the growth of disordered phase in both NCPs. This was accompanied by a rise in the refractive index for both the PC-PBT/Cr2O3 and PC-PBT/CdS NCP films, leading to an enhancement in their isotropic nature. The Cr2O3 NPs were found to be more effective in changing the band gap energy and refractive index due to the presence of excess oxygen atoms that help with the oxygen atoms of the carbonyl group in increasing the chance of covalent bonds formation between the NPs and the PC-PBT blend. Moreover, the color intensity, ΔE has been computed; results show that both the two synthesized NCPs have a response to color alteration by γ irradiation, but the PC-PBT/Cr2O3 has a more response since the values of ΔE achieved a significant color difference >5 which is an acceptable match in commercial reproduction on printing presses. According to the resulting enhancement in the optical characteristics of the developed NCPs, they can be a suitable candidate as activate materials in optoelectronic devices, or shielding sheets for solar cells.

Stability Investigation in the Optical Properties of Thermally Evaporated Ge5Se95-x Znx Thin Films

2015 ◽  
Vol 7 (3) ◽  
pp. 1923-1930
Author(s):  
Austine Amukayia Mulama ◽  
Julius Mwakondo Mwabora ◽  
Andrew Odhiambo Oduor ◽  
Cosmas Mulwa Muiva ◽  
Boniface Muthoka ◽  
...  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Thermal Evaporation ◽  
Optical Transition ◽  
Bulk Material ◽  
Band Gap Energy ◽  
Optical Absorbance ◽  
Gap Energy ◽  
Constituent Elements

 Selenium-based chalcogenides are useful in telecommunication devices like infrared optics and threshold switching devices. The investigated system of Ge5Se95-xZnx (0.0 ≤ x ≤ 4 at.%) has been prepared from high purity constituent elements. Thin films from the bulk material were deposited by vacuum thermal evaporation. Optical absorbance measurements have been performed on the as-deposited thin films using transmission spectra. The allowed optical transition was found to be indirect and the corresponding band gap energy determined. The variation of optical band gap energy with the average coordination number has also been investigated based on the chemical bonding between the constituents and the rigidity behaviour of the system’s network.

Sign in / Sign up

Export Citation Format

Share Document