DFT insights into the effects of substitutionally doped Sb defects in CuIn(S,Se)2 solar cell absorber Elham Mazalan, Muhammad Safwan Abd Aziz, Nor Aishah Saidina Amin Physica Scripta, 2023 Metal chalcogenide-based semiconductors are gaining attention for optoelectronic applications like thin-film photovoltaics (PV). Sb dopant incorporation in CuIn(S,Se)2 (CISSe) solar cell has been proven to significantly enhance PV performance, as demonstrated in our previous experimental work. However, the underlying mechanisms behind this improvement remained unclear. In this study, we report on the influence of substitutionally doped Sb defect on the structural, formation energy, band structure, and optical absorption properties in CISSe, employing the hybrid HSE06 functional within the density functional theory framework. We find that the Sb prefers to substitute at In site, resulting in the most stable Sb-doped CISSe structure. Under cation-poor growth conditions, Sb prefers to substitute on In sites, while under anion-poor growth conditions, it shows a preference for substituting on Se sites. Interestingly, only SbIn defects do not form impurity states in the band gap. Additionally, SbIn, SbS, and SbSe show a reduction in the band gap. Our results reveal that Sb-doped CISSe exhibits enhanced optical absorption in the IR to visible regions, leading to increased photocurrent generation and improved photovoltaic device efficiency, consistent with our experimental findings. These findings provide valuable theoretical insights into the influence of Sb-doping in CISSe, aiding the design of effective metal chalcogenide PV.
First-principles study on crystal structures and bulk modulus of CuInX2(X = S, Se, S-Se) solar cell absorber E Mazalan, M S A Aziz, N A S Amin, F D Ismail, M S Roslan, K Chaudhary Journal of Physics Conference Series, 2023 Chalcopyrite semiconductors are widely used as absorbers in thin film solar cells, especially flexible solar cells, due to their high power conversion efficiency. They also have interesting mechanical properties, making them promising materials for flexible, light, and thin solar cells. In this work, we report the first-principle calculations of the lattice constant and bulk modulus for CuInS2, CuInSe2, and CuIn(S,Se)2 absorber solar materials. All calculations are performed using plane wave as implemented in the Quantum ESPRESSO software package in the framework of density functional theory using PBE-GGA approximations and ultrasoft pseudopotentials. The calculated lattice constant correlates well with the available experimental study. The energy-volume and pressure-volume relations are described using the third order of Birch-Murnaghan’s equation of state to calculate the bulk modulus of the absorber solar material, which is associated to the hardness of a material under particular conditions. The values of bulk modulus obtained for CuInS2 and CuInSe2 are in good agreement with available theoretical results, except for CuIn(S,Se)2, which have been calculated and reported for the first time.
Effect of sample temperature on spectroscopic investigation of laser-induced aluminum and copper plasma E Mazalan, Z Haider, K Chaudhary, M Duralim, F D Ismail, M S Roslan, S N Wathiqah, J Ali Journal of Physics Conference Series, 2020 In this work, the influence of samples temperature and laser energy on the optical emission spectra and plasma parameters of laser-induced breakdown spectroscopy for aluminum and copper metallic target is investigated. The samples are uniformly cooled down to −70 °C and heated up to 200 °C by an external liquid nitrogen and ceramic heater, respectively. The plasma formed is generated by ablating the surface targets using Nd:YAG laser with laser energies of 100 mJ, 200 mJ and 300 mJ. The emission spectra at ambient atmospheric pressure are recorded using HR4000 spectrometer. From these spectra, plasma temperatures and electron densities are determined by using Boltzmann plot and Stark broadening methods, respectively. A significant increase in the peak intensity of spectral lines is observed with increase in the laser energy as well as sample temperature for both elements. Both of these parameters have shown a clear influence on dynamics of laser-induced plasma for each species. In brief, both laser energy and sample temperature affect the emission intensity, temperature and density of the laser-induced plasma generated from aluminum and copper samples.
Potassium doping effect on cu2znsn(S,se)4 thin film absorber layer deposited via spray pyrolysis Mohd Shahril Salleh, Kashif Tufail Chaudhary, Elham Mazalan, Jalil Ali Solid State Phenomena, 2020 This article reports on the role of potassium (K) as dopant in Cu2ZnSn (S,Se)4, CZTSSe thin film in context of optical properties. Thin film precursor solution is prepared in dimethyl sulfoxide (DMSO) solvent, and doped by K with six different concentrations. The prepared solution are deposited on heated soda lime glass (SLG) substrates using spray pyrolysis technique, followed by selenization process using three-step temperature approach. UV-Visible spectra show high absorption coefficient, α, more than 104cm-1 and bandgaps in narrow range 0.98eV to 1.10eV. X-ray diffractograms show that all samples exhibit kesterite structure with preferential orientation along (112) orientation. Field Emission Scanning Electron Microscopy was used to determine the morphologies of the K-doped CZTSSe thin films. 1.5 mol % of K has shown better characteristics as an absorber layer among other tested samples.
Growth of Wall-controlled MWCNTs by Magnetic Field Assisted Arc Discharge Plasma M.S. Roslan, K.T. Chaudhary, N. Doylend, A. Agam, R. Kamarulzaman, Z. Haider, E. Mazalan, J. Ali Journal of Saudi Chemical Society, 2019 Carbon nanotubes have long attracted great scientific interest because of their simplicity, ease of synthesis and unique properties. The novel properties of nanostructured carbon nanotubes including its high surface area, stiffness, tensile strength, thermal and electrical properties which become suitable for the application in the fields of energy storage, hydrogen storage, electrochemical supercapacitor, field-emitting devices, transistors, nanoprobes and sensors, composite material, templates, etc. In this study, carbon nanotubes were synthesized through arc discharge plasma with two different configurations, transverse and axial field, applied across arc plasma synthesis process to enable a much rapid rate growing of tubular carbon multi-walled carbon nanotubes (MWCNTs). TEM, FESEM, RAMAN, FTIR and XRD were used to investigate the morphology and structural evolution of the MWCNT samples produced with different synthesis environment. Introduction of magnetic field during the MWCNTs synthesized through arc discharge plasma technique has also been found to enhance the carbon nanotube growth, increase the high aspect ratio and its chemical stability, and shows potential for regulating the number of walls formed.
Determination of calcium to phosphate elemental ratio in natural hydroxypatite using LIBS Elham Mazalan, Kashif Chaudhary, Zuhaib Haider, Siti Fatimah Abd Hadi, Jalil Ali Journal of Physics Conference Series, 2018 In this work, laser induced breakdown spectroscopy (LIBS) is employed for determination of calcium to phosphate (Ca/P) ratio in hydroxyapatite (HA) extracted from animal bones. HA was extracted from the biological bones of lamb, bovine, and fish separately. Fresh bones were boiled in deuterium-depleted water (DDW) for 4 hours and immersed it in acetone for 15 hours followed by drying process in the oven. Dried bones were heated at 600 °C and crushed into powder form which was then mixed with potassium bromide (KBr) in a known quantity. The mixture for each sample was palletized into pellets of identical mass using a hydraulic press. The palletized samples of HA extracted from the bones were ablated with 10 ns Q-switched Nd-YAG laser pulses having an energy of 320 mJ/pulse. The optical emissions produced from the laser induced plasma were recorded. Ca and P emission lines are identified and the Ca/P is calculated. Ca/P ratio by LIBS analysis has been verified by EDX measurements and are found in good agreement.
Development of automated system for real-time LIBS analysis Elham Mazalan, Jalil Ali, Kashif Tufail, Zuhaib Haider Aip Conference Proceedings, 2017 Recent developments in Laser Induced Breakdown Spectroscopy (LIBS) instrumentation allow the acquisition of several spectra in a second. The dataset from a typical LIBS experiment can consist of a few thousands of spectra. To extract the useful information from that dataset is painstaking effort and time consuming process. Most of the currently available softwares for spectral data analysis are expensive and used for offline data analysis. LabVIEW software compatible with spectrometer (in this case Ocean Optics Maya pro spectrometer), can be used to for data acquisition and real time analysis. In the present work, a LabVIEW based automated system for real-time LIBS analysis integrated with spectrometer device is developed. This system is capable of performing real time analysis based on as-acquired LIBS spectra. Here, we have demonstrated the LIBS data acquisition and real time calculations of plasma temperature and electron density. Data plots and variations in spectral intensity in response to laser ene...
