ZnS Buffer Research Articles

Advancements in CIGS/ZnS heterojunction solar cells: Experimental and numerical analysis

This study presents a comprehensive experimental investigation conducted on a CIGS-based solar cell incorporating a ZnS buffer layer. The primary objective was to determine key parameters of the CIGS/ZnS heterojunction, including parasitic resistances (Rs and Rsh), ideality factor (n), and barrier height (ϕB), using experimental current-voltage (I-V) characteristics over a temperature range of 150 K to 300 K under dark conditions. The heterojunction was modelled using a single-diode electrical circuit that accounted for parasitic resistances. Two methods were employed for parameter determination: direct analysis of the (I-V) curves and Cheung's method. Additionally, the charge transport mechanism within the heterojunction is investigated and discussed. Furthermore, the performance of the Al:ZnO/i:ZnO/ZnS/CIGS/Mo solar cell was assessed using the SCAPS-1D simulator, demonstrating an initial solar energy conversion efficiency of 15.01 %. To enhance this efficiency, a hole transport layer (HTL) was integrated between the back electrode and the absorber layer. Extensive studies were conducted to optimize the thickness and doping density of the HTL, including a comparative analysis of different materials used as HTLs. These optimizations resulted in a significant increase in conversion efficiency, reaching up to 28.68 %.

Enhanced luminescence using the core‐shell‐shell structure of 3‐mercaptopropionic acid‐capped ZnSe/ZnS: Mn/ZnS quantum dot

AbstractIn this study, we used the surface stabilizer 3‐mercaptopropionic acid (MPA) to synthesize ZnSe quantum dots in nontoxic aqueous solvents. Because of the –COOH group, MPA is an SH‐R‐COOH molecule that is added to improve the dispersion and quantum dot (QD) compatibility with antibodies. The different structures ZnSe, Mn‐doped ZnSe, Mn‐doped ZnSe/ZnS, and ZnSe/Mn‐doped ZnS/ZnS were investigated to find the optimum photoluminescence (PL). The structure and distribution element of ZnSe/Mn‐doped ZnS/ZnS QD were analyzed by the high‐resolution TEM image and scanning transmission electron microscopy. This finding of the ZnS buffer layer helps to reduce the defect lattice of QDs, which increases PL significantly. The highest PL intensity of ZnSe/ZnS:Mn/ZnS is significantly more than that of ZnSe and ZnSe/ZnS 6.2 and 3.3 times, respectively. In addition, the fluorescence efficiency of ZnSe/ZnS:5%Mn/ZnS‐MPA was 74.37% higher than that of ZnSe:5%Mn/ZnS‐MPA (55.04%) in ZnS buffer.

Performance enhancement of CIGS/CZTS-based thin film solar cell using non-toxic ZnS buffer layer: a simulation approach

Performance enhancement of CIGS/CZTS-based thin film solar cell using non-toxic ZnS buffer layer: a simulation approach

Effect of bath temperature on the efficiency and properties of Cu2O/ZnS/ZnO heterojunctions thin film prepared by electrodeposition and chemical bath deposition methods

A novel p-n type Cu2O/ZnS/ZnO heterojunction thin film was successfully fabricated by a combination of electrodeposition and chemical bath deposition techniques. The effect of bath temperature (T = 75, 80, 85, 90 °C) on the growth of ZnS layers was investigated. The influence of ZnS buffer layers on the properties and efficiency of the prepared heterojunction thin films were examined using XRD, FE-SEM, AFM, EDS, UV–Vis, and electrochemical measurements. The analysis of prepared films revealed that the Cu2O/ZnS/ZnO heterojunction exhibits a unique combination of hexagonal structure of ZnO and the cubic structure of Cu2O. It was found that all the heterojunction films exhibit the growth of composed pyramids and corner grains with a homogenous distribution. The optical band-gap of the deposited ZnS buffer layers decreased from 3.46 eV to 3.35 eV with an increase of bath temperature from 75 °C to 90 °C. Moreover, the obtained results revealed that the thicknesses and the surface roughness of ZnS buffer layers increased when bath temperature increased. Mott-Schottky results of the heterojunctions indicate a p-type semiconductor behavior for the Cu2O, while it was observed an n-type semiconductor behavior for the ZnO and ZnS layers. As a result, the photocurrent response of Cu2O/ZnO heterojunctions with ZnS layer insertion was enhanced from 0.175 to 0.730 mA, which can be attributed to the reduced electron transfer resistance, enlarged photo-generated (e−/h+) carrier separation efficiency, and enhanced light absorption due to the presence of ZnS buffer layers. These results highlight the advantages of the bath temperature on the deposition of ZnS for photoelectrochemical and solar cells applications.

Investigation of suitable buffer layer for PbS-TBAI/PbS-EDT colloidal quantum dot solar cell using SCAPS-1D

Colloidal quantum dots (CQD) are emerging third-generation photovoltaic technologies because of their ability to link a wider range of the light spectrum compared to those of perovskite, crystalline, and copper indium gallium selenide (CIGS) solar cells. In this work, a Lead Sulphide (PbS) CQD solar cell architecture with Ag2S, CdS, ZnSe and ZnS buffer layer is presented. The device consisting of PbS-tetrabutyle ammonium iodide (PbS-TBAI) as an absorber layer, PbS-1,2-ethanedithiol (PbS-EDT) as a hole transport layer (HTL), TiO2 as an electron transport layer (ETL), and fluorine tin oxide (FTO) as an oxide layer. The electrical performances of the solar cells were simulated using SCAPS-1D while taking into account different buffer layers with increasing bandgap values. With ZnS acting as a buffer layer, the computational modelling and analysis of architectural PbS CQD solar cell result in an efficiency of 17.12%. Additionally, the parameters of the solar cell have been studied to be affected by the thickness and bandgap of the absorber and HTL layers, the effect of acceptor concentration with various buffer layers, the impact of temperature, the effect of HTL doping density, and the effect of absorber layer defect density. This study can serve as a guide for future PbS CQD solar cells.

Simulation and performance analysis of CdTe thin film solar cell using different Cd-free zinc chalcogenide-based buffer layers

In this study, the performance of a Cadmium Telluride (CdTe) thin-film solar cell was evaluated with various buffer layers (CdS, ZnSe, ZnO, ZnS) using the Silvaco-Atlas semiconductor device simulator. The impact of these buffer layers on the functionality of the CdTe solar cell was scrutinized at a temperature of 300 K under standard AM1.5G illumination. Initially, the modeling and simulation results of CdS/CdTe solar cell were examined, in comparison with the experimental and simulation results previously reported, to validate our reference structure and to explore its performance. The baseline CdS/CdTe solar cell, serving as a benchmark, yielded a conversion efficiency of 22.14 %. Then we attempted to identify an environmentally friendly alternative buffer layer for the CdTe thin film solar cell by substituting CdS with various Cd-free zinc chalcogenide-based materials (Zn(O,S,Se)) to boost efficiency. By trimming the layer thickness to approximately 0.01 μm, conversion efficiencies of 23.04 %, 23.13 % and 24.48 % were attained for the ZnO, ZnSe, and ZnS buffer layers, respectively. In order to investigate the performance of each proposed structure, thickness and doping density of the absorber and buffer layer were varied. Best efficiency around 25.23 % and 25.04 % are achieved for the optimized solar cells for ZnS and ZnSe buffer layer, respectively. As a result, ZnS and ZnSe are promising materials can be used as an alternative to the commonly used CdS buffer layer in CdTe solar cell. The influence of the operating temperature on solar cell performance was also investigated.

Starch Assisted the ZnS Buffer Layer in Enhancing the Photoluminescence of ZnSe/ZnS:Mn/ZnS Quantum Dots for Detecting E. Coli and MRSA Bacteria Quickly.

In this study, we used a starch paste stabilizer to synthesize ZnSe: Mn/ZnS- Starch and ZnSe/ZnS: Mn/ZnS-starch quantum dot (QDs) in a non-toxic aqueous solvent. The -CH2-OH group of the starch paste promotes dispersibility and improves the compatibility of quantum dots with antibodies, its bonding is observed in the FTIR spectrum. Besides, the Mn-doped ZnS buffer shell with various concentrations (1, 3, 5, 7, and 9%) influence structure, optical, and photoluminescence of QDs properties were investigated in detail. The greatest luminescence intensity is achieved at a molar ratio of 3% Mn2+/Zn2+. Moreover, the ZnS: Mn buffer shell helps to enhance the fluorescence intensity and quantum yield (QY) of the ZnSe/ZnS: Mn/ZnS QDs, which are higher than ZnSe: Mn/ZnS-starch QDs. Through protein A and EDC bridging, ZnSe/ZnS:3%Mn/ZnS- Starch resulted in good signal and sensitivity, with no toxicity to E. coli O157:H7 and MRSA strains.

Design and Numerical Analysis of Thin Film Solar Cells Based on Cu₂ZnSn (SₓSe₁₋ₓ)₄ with SnO₂ TCO and ZnS Buffer

Due to their earth-abundance, direct and adjustable bandgap in the range of visible light, and lower fabrication cost on large areas, Cu2ZnSn(SxSe1-x)4 semiconductors, commonly known as kesterite, are gaining recognition as potential materials for affordable, environment‐friendly, and high‐efficiency thin‐film photovoltaics. In this work, we numerically investigated the performance parameters of a single-heterojunction solar cell using Cu2ZnSnS4 (CZTS) / Cu2ZnSnSe4 (CZTSe) absorber layer and ZnS buffer layer, with SnO2 transparent conducting oxide (TCO) under a range of operating conditions and cell parameters. Maximum efficiency of 20.68% was obtained for a 5.5 µm absorber layer with 0.01 µm ZnS buffer layer for Cu2ZnSnSe4 solar cell, and 22.86% was obtained for a 6 µm thick Cu2ZnSnS4 absorber layer with 0.03 µm ZnS layer at room temperature and standard irradiance. The increase of irradiance to thrice the standard value led to 1% and 5% increase in efficiency for CZTS and CZTSe cells, respectively. Efficiency increased by 39% and 6.6% when the front surface was textured at an angle of 90° for CZTS and CZTSe cells, respectively. The CZTS and CZTSe based solar cells with optimized thickness and 90° textured front surface with three times the standard irradiation, showed 25.59 % and 21.52 % efficiency with open circuit voltage 1045 mV and 579.4 mV and short circuit current 85.84 mA/cm2 and 140.7 mA/cm2, respectively. The proposed architecture in this study will help produce next-generation solar cells that are both economical and energy-efficient.

Modeling and simulation of CZTS based solar cells with ZnS buffer layer and ZnO:F as a window layer using SCAPS-1D

ZnS is an excellent candidate for the substitution of the CdS buffer layer inCZTS based solar cells, is nontoxic and is relatively less costly.It has been shown that a surface composition adaptation is favorable for the replacement of the buffer layer CdS by ZnS so as to obtain an interface quality with the CZTS layer that makes it possible to control the diffusion phenomenon of faults to this interface. SCAPS-1Dsoftware is used to simulate CZTS/ZnS/ZnO:F thin-film solar cell where the key parts are p-CZTS absorber layer and n-ZnS buffer layer.

The effect of ZnS buffer layer on Cu2SnS3 (CTS) thin film solar cells performance: Numerical approach

The aim of this paper is to optimize a new structure of Cu2SnS3 (CTS) thin-film based solar cells by using the one-dimensional solar cell capacitance simulator (SCAPS 1D). We proposed ZnS as a non-toxic buffer layer and ITO as a window layer, neither of which has been reported with a CTS absorber layer. The effects of various parameters that affect CTS thin-film solar cell performance, such as thickness of the absorber layer, carrier concentration, band gap, and temperature, are investigated. The generation and recombination rates in both structures, Mo/CTS/ZnS/ITO and Mo/CTS/CdS/ITO, are studied. The results reveal that solar cell performance is enhanced within the range of 5e+16–2e+17 cm−3 of carrier concentration and 1.3–1.5 eV of band gap of CdS. The recombination rate at the CTS/ZnS interface is significantly lower compared to the CTS/CdS interface, indicating good conduction band alignment between the CTS absorber and ZnS buffer. Under the optimum parameters, power conversion efficiency (PCE) of CTS-based solar cells was boosted from 16.53% to 17.05% when ZnS was used as a buffer layer instead of CdS.

Effects of temperature, thickness, electron density and defect density on ZnS based solar cells: SCAPS-1D simulation

Using real input parameters from our experimental results of ZnO:Al, ZnS, and CZTS thin films, a numerical simulation using SCAPS-1D (Solar Cells Capacitance Simulator one-dimensional) software has been performed to evaluate the solar cell characteristics by giving the variations of the short-circuit current density (Jsc), the open circuit voltage (Voc), the fill factor (FF), and the efficiency parameters. The effects of temperature, thickness, electron density, and defect density on ZnS buffer layer with different concentration has been investigated. The results show a strong dependence on the studied parameters with a maximum efficiency of 11.86 % achieved for 0.1 M concentration, 10 nm of thickness, 1 × 1014 cm−3 of defect density, 300 K of operating temperature, and 1 × 1018 cm−3 of electron density.

Simulation and Numerical Modelling of CIGSSe-Based Solar Cells by AFORS-HET

A general equation to determine properties of penternary solar cell based on Cu (In, Ga) (Se, S) 2 (CIGSSe) with a double buffer layer ZnS/Zn0.8Mg0.2O(ZMO) were derived. Numerical analysis of a (CIGSSe) solar cell with a double buffer layer ZnS/ZMO, CdS free absorber layer, were investigated using the AFORS-HET software simulation. Taking into consideration the effect of thickness and doping concentration for the CIGSSe absorption layer, ZnS buffer layer and ZnO:B(BZO) window layer on the electron transport, short circuit current density (Jsc) and open circuit voltage (Voc); numerical simulation demonstrated that the changes in band structure characteristics occurred. The solar energy conversion efficiency is 28.34%, the filling factor is 85.59%, the open circuit voltage is 782.3 mV, the short circuit current is 42.32 mA. then we take the range of the gradient between the ratio of x and y for the absorption layer, and the best result of Voc, Jsc, FF, Eff equal (838.7 mV, 40.94 mA/cm2, 86.23%, 29.61%) respectively at x= 0, y= 0.26.

Enhancing the Performance of an Sb2Se3-Based Solar Cell by Dual Buffer Layer

In an Sb2Se3-based solar cell, the buffer layer is sandwiched between the absorber and the window layer, playing an essential role in interfacial electricity. Generally, CdS is used as a buffer layer, but its toxic nature and low bandgap can cause current loss because of parasitic absorption. In this work, we optimized the buffer layer by using ZnS as an alternative to the CdS buffer layer in order to decrease the use of CdS. The effect of different buffer layers on the solar device was explored by numerical simulation with the help of SCAPS 1D software. The basic parameters, such as open-circuit voltage (Voc), current density (Jsc), fill factor (FF), and efficiency (η) were analyzed and compared for both the buffer layers (CdS/ZnS). The results demonstrate that changing buffer materials and thicknesses has a significant impact on cell performance. The efficiency for the ZnS buffer layer was lower compared to that of the CdS-based solar cells because of insufficient energy band alignment. In order to enhance the efficiency of Sb2Se3-based solar cells, we used CdS/ZnS dual buffer layers and studied the device performance. The work function of the back contact also affects the device performance, and for work functions below 4.8 eV, the device’s efficiency was very low. The effect of varying the thicknesses and temperatures of the buffer layers on the I-V/C-V characteristics, quantum efficiency, and energy band structure are also reported. This study shall guide the researcher in reducing CdS and improving the device’s performance.

Theoretical simulation of ZnS buffer layer thin films with SCAPS-1D software for photovoltaic applications

This Work represents the influence of some parameters (Temperature, existence of Buffer layer and its thickness), using a Numerical simulation of thin film solar cells, named SCAPS (which is a one-dimensional solar cell capacitance simulator) in modeling of the high efficiency CIGS-based solar cells (with efficiency of η=10.87%).In each case, the photovoltaic parameters have been calculated. It has been concluded that, the efficiency of CIGS-based solar cells is decreasing with increasing of the temperature and the thickness of Zinc Sulfide buffer layer. However, when the buffer layer doesn’t exist in solar cells photovoltaic, we noticed that the efficiency of solar cells is increasing to (η=12.04%) under the AM1.5 spectrum, one sun and at room temperature, with increasing of the short-circuit current density (Jsc), and decreasing of open-circuit voltage (Vco).

Investigation of Cu2ZnSnS4 thin film with preannealing process and ZnS buffer layer prepared by magnetron sputtering deposition

Unlike traditional methods for fabricating a CdS buffer layer through chemical bath deposition in thin-film solar cells, this study fabricated a ZnS thin film by sulfurizing the Zn film that was deposited using a magnetron sputtering system at varied temperatures from 500° to 560 °C in a sulfurization furnace. The ZnS thin film have been used as a buffer layer on the Cu2ZnSnS4 absorption layer. In this study, the Cu2ZnSnS4 absorber layer was prepared by first depositing a copper–zinc–tin (CZT) precursor film with a metal stack order of Zn–Sn–Cu–Zn through magnetron sputtering, followed by a preannealing process on the CZT precursor, to promote the interdiffusion of elements for the transfer of the metal phase into the alloy phase. Experimental results revealed the increased crystallite size in the SEM observation, an enhanced Raman intensity at 336 cm−1, and a reduced FWHM value in the XRD study for the Cu2ZnSnS4 thin film fabricated at a sulfurization temperature of 510 °C for 20 min with a preannealing treatment of the CZT precursor at a temperature of 420 °C for 30 min. In addition, the improved optical transmittance to 81.3% and an increased optical band gap value to 3.28 eV due to the reduced grain boundaries was obtained for the ZnS film with improved crystallinity quality fabricated at a sulfurization temperature of 560 °C.

Investigation of Cu2ZnSnS4 solar cell buffer layer fabricated via spray pyrolysis

Copper zinc tin sulfide solar cells were fabricated by using spray pyrolysis from a window layer to an absorber layer. ZnS and In2S3 buffer layers were deposited on the TiO2 layer, and the photovoltaic characteristics were investigated. The ZnS buffer demonstrated a poor photovoltaic performance because of its poor surface coverage and micro-cracks at fluorine-doped tin oxide/TiO2 layers. The In2S3 buffer layer sprayed at low temperature (<360 °C) showed a large difference between photo and dark currents beyond the open-circuit voltage (VOC). When the spraying temperature exceeded 390 °C, the devices showed high dark leakage currents at reverse biases because of the high conductivity of the buffer layer, resulting in decreased VOC and short-circuit current density (JSC). The optimum temperature for spraying In2S3 is 360 °C, and the best performing device showed 410 mV, 30.4 mA/cm2, 35.3%, and 4.4% of VOC, JSC, fill factor, and efficiency, respectively.

Analysis of CIGS-based thin film tandem solar cell with ZnS buffer layers

In this paper, a thin film tandem solar cell based on CGS/CIGS structure incorporating ZnS buffer layers has been designed and its performance characteristics were obtained using Silvaco-Atlas 2D numerical simulator. A tandem cell with CdS buffer layers was also modeled and simulated with the same method for reference. Our results show that the tandem solar cell with ZnS buffer layers has a maximum conversion efficiency of 28.34% compared to a maximum conversion efficiency of 26.85% obtained for CdS-based tandem solar cell used as a reference. The maximum conversion efficiency for theoretically studied CdS-based tandem solar cell found in literature is 26.21%. Thus, ZnS can be used as a potential replacement for CdS that is notoriously known as a highly toxic compound. Optimum values of doping concentration and thickness are obtained for all layers of the solar cell. In addition, the effect of temperature on ZnS-based CGS/CIGS tandem cell was studied.

An emerging high performance photovoltaic device with mechanical stability constants of hybrid (HC(NH2)2PbI3) perovskite

Here in, we present the extensive analysis of the parameters associated with structural, electronic, optical and mechanical properties of HC(NH2)2PbI3 or FAPbI3 (FA = Formamidinium) by using full potential linearized augmented plane wave method (FP-LAPW) within framework on the density functional theory. The band structure shows that FAPbI3 has a direct band gap (1.44 eV) at the symmetry point R (0.5, 0.5, 0.5) and are in best agreement with experimental data. The strong hybridization of s orbitals of Pb and p orbitals of I in valance band plays an important role in the structural stability. From the mechanical constants, we have observed that this is ductile in nature and perfect use for photovoltaic applications. Further, FAPbI3 photovoltaic device has been prepared and device parameters have discussed for ZnO, ZnS, ZnSe, ZnTe and CdS buffer layers. The calculated results for FAPbI3 thin layer solar cell show maximum efficiency (20.48% and 20.77%) with ZnS and CdS buffer layers respectively. The proposed results further validate the prospects of methylammonium (MA) free perovskites and it would be persistent and consistent with the flexible substratum. These are the main features of commercialization perovskite solar cells. Thus, promoting the evolution of cubic FAPbI3, for achieving high performance-based optoelectronic devices and will pave a new path in solar cell industry.

A comparative study on generation and recombination process of kesterite CZTS based thin film solar cells for different designs

In this paper, a comparative study on generation and recombination process in different CZTS designs has been carried out in which their performances and band alignment are invistigated. Firstly, CdS/CZTS design has been modeled using the SCAPS-1D. Secondely, new designs have been proposed in which a back surface field (BSF) layer is inserted and CdS layer is replaced by ZnS. The obtained results exhibit a boosted efficiency from 12.03 % to 14.14 % by inserting a BSF layer with a ZnS buffer layer. The analysis of generation and recombination reveals a high recombination in CdS/CZTS interface in comparaison with ZnS/CZTS due to the high density of defect states at the CdS/CZTS interface. BSF increases recombination in P-region. Whereas, it fairly impacts generation process. ZnS/CZTS/BSF design enhances the collection efficiency in short and long wave length regions resulting in higher solar cell performances (VOC =0.89 V, JSC =25.38mA/cm2, FF=62.44 %, η=14.14 %).

Achieving desired quality of ZnS buffer layer by optimization using air annealing for solar cell applications

The possibility of maximum transmittance at lower thickness of light transmitting ZnS layer and its optimization by air-annealing as an alternative to hazardous and expensive CdS is reported in this communication in order to achieve better buffer layer for solar cells. Thin films of ZnS were deposited using e-beam evaporation on glass and ITO substrates and subjected to air-annealing followed by characterizations for physical properties. XRD patterns revealed amorphous behavior which transformed into cubic (111) plane with change of substrate and annealing whereas surface topography reveals hill and deep valley like structures. Optimal transmittance of maximum 95% in visible region, direct band gap of 3.38 eV and maximum electrical conductivity were observed for 200°C annealed films. The study refers that films annealed at 200°C are claimed to be suitable for buffer layer applications.