Absorber Layer In Solar Cells Research Articles

Investigating the Impact of Interfacial Layers on Device Performance of Highly Stable Cs2InBiBr6 Based Double Perovskite Solar Cells

AbstractPerovskite solar cells, a third‐generation photovoltaic technology, have recently emerged as a game‐changing innovation. However, lead (Pb) is a toxic heavy metal, and it is crucial to explore lead‐free perovskite solar cells with continuously improving efficiency for long‐term development. Recently, materials researchers have discovered a lead‐free double perovskite solar cell material, Cs2InBiBr6 with a small direct bandgap of 1.27 eV and strong thermodynamic and mechanical structural stability. The power conversion efficiency of Cs2InBiBr6‐based perovskite solar cells is not reported yet. To investigate its potential, a solar cell capacitance simulator to analyze the solar cell structure of FTO (Fluorine Doped Tin Oxide)/ETL (Electron Transport Layer)/Cs2InBiBr6/HTL (Hole Transport Layer)/Au, selecting appropriate hole transport materials and electron transmission materials to achieve high efficiency is used. Moreover, this study explores the impact of several factors, including absorber layer thickness, acceptor and donor doping density, and the influence of total defect density of the perovskite and interface layers on the performance of solar cells. Advanced device characterization methods such as Mott‐Schottky analysis are performed to unravel the effect of interfaces on the device performance. The solar cell with the device structure FTO/TiO2/Cs2InBiBr6/Cu2O/Au achieves an outstanding PCE of 23.64% demonstrating the immense potential of Cs2InBiBr6 as a lead‐free double perovskite solar cell absorber layer.

Two-dimensional CsPbI3/CsPbBr3 vertical heterostructure: a potential photovoltaic absorber

First-principles methods have been employed here to calculate structural, electronic and optical properties of CsPbI3 and CsPbBr3, in monolayer and heterostructure (HS) (PbI2-CsBr (HS1), CsI-CsBr (HS2), CsI-PbBr2 (HS3) and PbI2-PbBr2 (HS4)) configurations. Imaginary frequencies are absent in phonon dispersion curves of CsPbI3 and CsPbBr3 monolayers which depicts their dynamical stability. Values of interfacial binding energies signifies stability of our simulated heterostructures. The CsPbI3 monolayer, CsPbBr3 monolayer, HS1, HS2, HS3 and HS4 possess direct bandgap of 2.19 eV, 2.73 eV, 2.41 eV, 2.11 eV, 1.88 eV and 2.07 eV, respectively. In the HS3, interface interactions between its constituent monolayers causes substantial decrease in its resultant bandgap which suggests its solar cell applications. Static dielectric constants of all simulated heterostructures are higher when compared to those of pristine monolayers which demonstrates that these heterostructures possess low charge carrier recombination rate. In optical absorption plots of materials, the plot of HS3 displayed a red shift and depicted absorption of a substantial part of visible spectrum. Later on, via Shockley-Queisser limit we have calculated solar cell parameters of all the reported structures. The calculations showed that HS2, HS3 and HS4 showcased enhanced power conversion efficiency compared to CsPbI3 and CsPbBr3 monolayers when utilized as an absorber layer in solar cells.

A-Site Cation Replacement of Hydrazinium Lead Iodide Perovskites by Borane Ammonium Ions: A DFT Calculation.

Organometallic perovskites have become one of the most common multifunctional materials in optoelectronic research fields. This research studies density functional theory calculation on orthorhombic hydrazinium lead iodide (N2 H5 PbI3 ) perovskite by replacing A-site cation with a borane ammonium (BH2 NH3 + ) ion. The perovskite showed a significant structural deformation and an orthorhombic to triclinic phase transition due to A-site ion replacement. The N2 H5 PbI3 perovskite has a band gap of 1.64 eV, suitable for the solar cell absorber layer. The band gap has increased to 2.12 eV after complete A-site ion replacement. All structures showed a high absorption coefficient over 104 cm-1 in the low wavelength region and an increase in refractive index from 2.5 to 2.75 due to ion replacement. All the structures showed high optical conductivity of 1015 s-1 order in the blue wavelength region. These new perovskite structures hold the potential to provide a revolution in optoelectronic research.

Synthesis and characterization of lithium-doped copper zinc tin sulfide (CZTS) thin films

The non-toxic nature and remarkable optoelectronic properties of kesterite (Cu2ZnSnS4 and CZTS) make CZTS a potential candidate for solar cell absorber layer material. Since alkali metal doping has shown a performance boost of active layers of solar cells, this work investigates the effects of significant lithium doping on sol-gel-produced CZTS thin films. CZTS- and lithium (Li)-doped CZTS thin films were prepared using the spin coating technique. The variation of structural, morphological, and optical properties of CZTS due to Li-doping has been studied by x-ray diffraction, scanning electron microscopy, and UV–visible spectroscopy techniques. All the synthesized LixCu2−xZnSnS4 (x = 0, 0.2, 0.4, 0.6) films showed fine crystallinity with average crystallite sizes of 4.745, 6.013, 6.255, and 6.404 nm, respectively. The average grain size decreases from 0.336 to 0.310 µm via increasing Li concentration. The inclusion of Li increased the bandgap energy ranges from 1.5 to 1.808 eV. The Li0.6Cu1.4ZnSnS4 thin showed the highest absorption coefficient of 3.505 × 104 cm−1 among all the prepared thin films. A high optical conductivity over 1014 s−1 was observed for CZTS, which further increased with an increased Li concentration. The synthesized structures showed enhanced characteristics suitable for solar cell application.

3D and Multimodal X-Ray Microscopy Reveals the Impact of Voids in CIGS Solar Cells.

Small voids in the absorber layer of thin-film solar cells are generally suspected to impair photovoltaic performance. They have been studied on Cu(In,Ga)Se2 cells with conventional laboratory techniques, albeit limited to surface characterization and often affected by sample-preparation artifacts. Here, synchrotron imaging is performed on a fully operational as-deposited solar cell containing a few tens of voids. By measuring operando current and X-ray excited optical luminescence, the local electrical and optical performance in the proximity of the voids are estimated, and via ptychographic tomography, the depth in the absorber of the voids is quantified. Besides, the complex network of material-deficit structures between the absorber and the top electrode is highlighted. Despite certain local impairments, the massive presence of voids in the absorber suggests they only have a limited detrimental impact on performance.

Numerical modeling and performance analysis of a novel Cd-free all-Kesterite tandem solar cell using SCAPS-1D

Tandem solar cells have the potential to surpass conventional single-junction photovoltaics by harnessing a wider range of the solar spectrum and reducing losses caused by thermalization and transmission. This study examines the performance of a kesterite-kesterite tandem solar cell with two different absorber layers in each subcell using SCAPS-1D. The upper subcell comprises CZTS and ACZTS with wider bandgaps, while the lower subcell comprises ACZTSe and CZTSe with narrower bandgaps. The CZTS- and CZTSe-based solar cells were first validated using experimental data to determine the feasibility of the tandem solar cell design. The CZTS-based solar cell was modified by replacing the back contact, adding a Cd-free buffer layer of ZnMnO, and using a SnMnO2 layer as a window layer. The band gap and electron affinity of ZnMnO and SnMnO2 layers were adjusted by changing their manganese contents for optimal conduction band offset. A thin ACZTS layer was also added as a second absorber layer in the CZTS-based solar cell to enhance open circuit voltage. The CZTSe-based solar cell was thereafter modified by including an ACZTSe layer as a second absorber layer and by selecting ZnSe as a buffer layer and optimizing the thicknesses of all layers. Both upper and lower subcells were analyzed for tandem configuration using filtered spectra and current-matching techniques. The thickness of the CZTS layer in the upper subcell was adjusted to achieve current matching; consequently, the proposed tandem cell had an efficiency of ∼24%. These findings provide valuable insights for future advancements in kesterite-kesterite-based tandem solar cells.

Identifying the photon absorption characteristics of Cr-doped Cu2ZnSnS4 (CZTS:Cr) thin film deposited by Co-sputtering technique

This study investigates the potential of a quaternary compound semiconductor to be realized as the absorber layer for third-generation intermediate band solar cells (IBSCs). In this work, the effects of Cr doping into Cu2ZnSnS4 (CZTS) host material to form intermediate band within the forbidden bandgap were studied. The films were deposited by a co-sputtering technique. It has been found that Cr has a high preference to substitute Zn, followed by Sn, then Cu. Insufficient Cr does not lead to intermediate band but, instead, forms defect states within the bandgap. Excess Cr however deteriorates CZTS (112) peak while at the same time secondary phase of cubic-ZnCr2S4 starts to grow. At sufficient levels of Cr content, absorption coefficient tremendously improved to 105 cm−1, resulting in an additional absorption peak attributed to possible formation of an intermediate band. This intermediate band is located at 1.40 ± 0.02 eV below CBM, while the band gap Eg is 1.55 eV. Further optimization to the sulphurization process reveals that the intermediate band peak, ECIL could be adjusted towards blue or red shift by manipulating Cr and/or sulphur content. This yields a bandgap of 1.52 eV with two intermediate bands positioned at 0.90 eV and 1.20 eV above the VBM. These preliminary findings are beneficial prior to realizing a working device of CZTS:Cr intermediate band solar cell.

Optoelectronic Evolution in Halogen-Doped Organic-Inorganic Halide Perovskites: A First-Principles Analysis.

Cl, Br, and I are elements in the halogen family, and are often used as dopants in semiconductors. When employed as dopants, these halogens can significantly modify the optoelectronic properties of materials. From the perspective of halogen doping, we have successfully achieved the stabilization of crystal structures in CH3NH3PbX3, CH3NH3PbI3-xClx, CH3NH3PbI3-xBrx, and CH3NH3PbBr3-xClx, which are organic-inorganic hybrid perovskites. Utilizing first-principles density functional theory calculations with the CASTEP module, we investigated the optoelectronic properties of these structures by simulations. According to the calculations, a smaller difference in electronegativity between different halogens in doped structures can result in smoother energy bands, especially in CH3NH3PbI3-xBrx and CH3NH3PbBr3-xClx. The PDOS of the Cl-3p orbitals undergoes a shift along the energy axis as a result of variances in electronegativity levels. The optoelectronic performance, carrier mobility, and structural stability of the CH3NH3PbBr3-xClx system are superior to other systems like CH3NH3PbX3. Among many materials considered, CH3NH3PbBr2Cl exhibits higher carrier mobility and a relatively narrower bandgap, making it a more suitable material for the absorption layer in solar cells. This study provides valuable insights into the methodology employed for the selection of specific types, quantities, and positions of halogens for further research on halogen doping.

Analysis of degradation of Sb2Se3 thin film solar cells deploying a time-dependent approach linked with 1D-AMPS simulation

In this paper, we have developed a time-dependent model to study defect growth in the absorber layer of Sb2Se3 thin film solar cells. This model has been integrated with the AMPS-1D simulation platform to investigate the impact of increasing defect density at different positions within the Sb2Se3 layer on the electrical parameters of the solar cell. We adopted the Gloeckler standard model for thin films in AMPS to represent Sb2Se3 materials. The study focuses on tracking the degradation of device performance parameters as donor-like mid-gap states accumulate in the Sb2Se3 layer over time. We monitored the variation of key electrical parameters, including efficiency (η), fill factor (FF), open-circuit voltage (Voc), and short-circuit current (Jsc), at three different positions: the interface with CdS, the bulk of the Sb2Se3 layer, and the interface with the top contact. These positions are susceptible to increasing defect density during prolonged operation and irradiation. To pinpoint the most sensitive part of the Sb2Se3 layer to defect accumulation, we divided the layer into three sub-layers. Our simulation results highlight that the CdS/Sb2Se3 interface is the most vulnerable position in the cell when it comes to defect accumulation. The practical implication of this study is that special attention should be given to the CdS/Sb2Se3 interface during material deposition and the development of high-stability Sb2Se3 thin film solar cells.“

An additive manufacturing approach based on electrohydrodynamic printing to fabricate P3HT:PCBM thin films

Additive manufacturing (AM) enables the production of high value and high performance components with applications from aerospace to biomedical fields. We report here on the fabrication of poly(3-hexylthiophene): phenyl-C61-butyric acid methyl ester (P3HT:PCBM) thin films through the electrohydrodynamic atomization (EHDA) process and its integration as absorber layer for organic solar cells. Prior to the film fabrication, the optimization of the process was carried out by developing the operating envelope for the P3HT:PCBM ink to determine the optimal flow rate and the appropriate applied voltage to achieve a stable-cone deposition mode. The EHDA printed thin-film’s topography, morphology and optical properties were systematically analyzed. The root-mean-square roughness was found to vary significantly with the annealing temperature and the flow rate and ranged from 1.938 to 3.345 nm. The estimated film mass and thickness were found between 3.235 and 23.471 mg and 597.5 nm to 1.60 µm, respectively. The films exhibited a broad visible absorption spectrum ranging from ~ 340 to ~ 600 nm, with a maximum peak λmax located at ~ 500 nm. As the annealing temperature and the flow rate were increased, discernible alterations in the PCBM clusters were consequently observed in the blends of the film and the size of the PCBM clusters has decreased by 3% while the distance between them was highly reduced by as much as 82%.

First-principles study of physical properties of Na2ZnIM6 (M = Br, Cl, Se) double perovskites

In this article, the physical properties of the double perovskites based on Na2ZnIM6 (M = Br, Cl, Se) are explored using the first-principles techniques. Investigations of the elastic properties in terms of elastic constants, bulk and shear moduli, anisotropy, Poisson’s ratio, and Young’s modulus reveal that these compounds are covalent and brittle. Furthermore, calculations of the electronic structures indicated them as semiconductors with wide and direct bandgaps. In optical properties, the dielectric constants (real and imaginary parts) were plotted against the frequency, and the trends in absorption, refraction, loss functions, and optical conductivities and their essential electronic and optical implications have been analyzed and discussed. Meanwhile, the studied compounds with strong absorptions, low reflections, and direct band gaps can be employed as photoelectric absorption layers in solar cells.

Harnessing the tunability of intrinsic defects in isovalent Zn doped spray deposited CuO thin films

Doping is a versatile tool for tailoring the properties of semiconductor thin films. This article investigates the influence of isovalent dopant, Zinc (Zn), on the electronic, optical and structural characteristics of copper oxide (CuO) thin films prepared by spray pyrolysis technique. Structural characterization from XRD and Raman studies confirms the successful incorporation of Zn atoms into the CuO lattice without altering monoclinic structure of the films. The absence of secondary phases like Cu2O and ZnO confirms the good quality of the prepared films. A significant variation in the morphology of the films was observed in FESEM images. The EDS analysis confirmed the incorporation of Zn atoms in CuO films and showed that the prepared films are oxygen rich in nature. The band gap of the films increased from 1.50 eV in pristine samples to 1.62 eV in 8 at% Zn-doped sample. Different defect related emissions were observed in PL spectra with the resultant emission in yellowish green region as obtained from chromaticity diagram. XPS analysis confirmed that both Cu and Zn are found in +2 oxidation state. The electrical conductivity and carrier concentration of CuO films improved with doping due to the enhanced oxygen interstitial defects. The carrier density increased from 2.17 × 1014 to 2.82 × 1015 cm−3 after 6 at %doping with the lowest resistivity of 708 Ω cm. Hence, the properties of CuO films can be effectively modified by Zn doping. Zn doping improved the electrical properties of the films without trading off the excellent optical properties of CuO thin films making them suitable in solar cell absorber layer applications.

Efficient modeling of double absorber layered structure in perovskite solar cells using machine learning techniques

This research article investigates the perovskite solar cells double absorber layer structure with 13 different absorber layer combinations. Our primary objective is to explore the potential for achieving high efficiency in perovskite solar cells. We present a double-layer structure for high efficiency, leveraging double absorber layers in perovskite solar cells expands spectral absorption and reduces thermalization losses, thereby enhancing power conversion efficiency and stability. Double absorber layer perovskite solar cells adaptability and integration potential further promise efficiency and reliability advancements. Through a comprehensive examination of all possible combinations of absorber layers we have identified a double absorber layer structure that exhibits an impressive efficiency exceeding 35%. To further enhance our understanding of the underlying factors influencing efficiency, we generated a dataset of 3490 samples. These samples were characterized by 20 input features and four attributes, including the efficiency of the perovskite structure. Leveraging machine learning approach, we developed model using the Random Forest algorithm to predict the efficiency and classify the structures into four distinct classes. Our findings contribute valuable insights into the optimized design of perovskite solar cells, offering a pathway towards achieving higher efficiencies and advancing the field of renewable energy.

Impact of absorber layer thickness and defect density on the performance of MAPbI3 solar cells based on CuO2 as hole transport material

Perovskite solar cells are a promising next-generation solar energy harvester because of their excellent photovoltaic performance and simple fabrication procedure. The high power conversion efficiency of this cell, together with its low cost of materials and processes, differentiates it from commercial silicon or other organic and inorganic solar cells. In this work, numerical simulation was performed using Solar Cell Capacitance Simulator (SCAPS)−1D for the device structure (FTO/HTM/ CH3NH3PbI3/ETM/Au) to analyze the impact of absorber layer thickness and defect density on various parameters of Photovoltaic cells. The purpose of this research was to explore the properties of CH3NH3PbI3-based solar cells with different HTM layers, such as Cu2O and ETM layers, such as SnO2, TiO2, and ZnO, respectively. Additionally, the thicknesses of the perovskite absorber are adjusted to obtain the highest photovoltaic efficiency, and the impact of the defect at the perovskite absorber layer on solar cell performance is also investigated. According to the findings of this article, the thickness of the absorber layer and defect density in a perovskite solar cell had a significant impact on JSC, FF, VOC, and efficiency. The findings show a substantial gain in efficiency (18%) when the ETM layer is ZnO. As the defect density of the absorber layer increases, the JSC, VOC, FF, and PCE values of perovskite solar cells decrease considerably. According to our findings, the ZnO as ETM is the most likely to provide a high photovoltaic (PV) efficiency when combined with Cu2O-based HTM.

First-principles calculations to investigate structural, mechanical, electronic, optical, and thermoelectric properties of novel cubic double Perovskites X2AgBiBr6 (X=Li, Na, K, Rb, Cs) for optoelectronic devices

ABSTRACT Structural, elastic, electronic, optical, and thermoelectric properties of cubic double perovskites X2AgBiBr6 (X = Li, Na, K, Rb, Cs) were investigated using the density functional theory (DFT) method. The DFT calculations were carried out with various exchange-correlation potentials, e.g. LDA, GGA-PBE, GGA-WC, and hybrid functionals (YS-PBE0). Structural and elastic properties of X2AgBiBr6 demonstrate that these compounds are ionically bonded, elastically stable, ductile, and anisotropic. Calculations show that the compounds are semiconductors with indirect bandgap at the (X- L) point, with bandgap values of 2.124, 2.222, 2.198, 2.209, and 1.902 eV for X2AgBiBr6 (X = Li, Na, K, Rb, and Cs), respectively. Due to their distinguishing optical characteristics and indirect wide bandgap, these compounds might be utilised as absorber layers in solar cells and other optoelectronic devices. Moreover, thermoelectric properties show that the Figure of Merit (ZT) has values of 0.713, 0.723, 0.721, 0.726, and 0.728 for X2AgBiBr6 (X = Li, Na, K, Rb, Cs). The Figure of Merit shows a plateau in the temperature range of 500–900 K, which corresponds to the highest value of ZT. All investigated compounds have holes as the majority of charge carriers. Thermoelectric properties of X2AgBiBr6 compounds reveal that these compounds can be employed in thermoelectric devices.

Effect of substrate temperature on the structural optical and electrical properties of new Cu2Cd0.8Mn0.2SnS4 photo-absorber layer for solar cells

We report for the first time the effect of substrate temperature on the structural, optical, and electrical properties of Cu2Cd0.8Mn0.2SnS4 new photovoltaic absorber layer. Cu2Cd0.8Mn0.2SnS4 thin films were deposited on soda lime glass (SLG) substrates by the spray pyrolysis method at different substrate temperatures. X-ray diffraction measurement revealed the formation of cernyite structure by Cu2Cd0.8Mn0.2SnS4 thin film. Also, an increase in crystal size from 7.23 to 14.35 nm and crystallinity improvement of Cu2Cd0.8Mn0.2SnS4 thin film with an increase in substrate temperature were achieved. The atomic force microscopy indicated an increase in surface roughness with substrate temperature. The elemental composition of the Cu2Cd0.8Mn0.2SnS4 thin films showed Cu-poor, S-poor, and Sn-poor conditions. The optical characterization showed that the absorption coefficient of Cu2Cd0.8Mn0.2SnS4 is in the order of 104 cm−1 and the bandgap decreased from 1.89 to 1.87 eV with an increase in substrate temperature. The refractive index dispersion parameters were discussed in terms of the Wemple-Didomenico and Sellmeier equations. Hall effect measurement indicated that the Cu2Cd0.8Mn0.2SnS4 films exhibit P-type conductivity. High hole mobility and the highest conductivity of 2.77 x104 cm2/Vs and 5.60 (Ω.cm)-1 respectively, were achieved at 400 °C substrate temperature. The Cu2Cd0.8Mn0.2SnS4 deposited at 400 °C is a potential candidate for use as a top absorber layer in the tandem solar cell.

Tungsten dopant incorporation for bandgap and type engineering of perovskite crystals

Organic–inorganic hybrid halide perovskites have shown to be viable semiconductor materials, as the absorber layer of solar cells. Unfortunately, the polycrystalline qualities of perovskite films result in nonuniform coverage or a high recombination rate, which weakens the photoelectric capabilities of thin films. Here, the pure and tungsten (W)-doped methylammonium lead bromide (CH3NH3PbBr3 or MAPbBr3) films are deposited to FTO-glass substrates using the sol–gel spin coating method. The W-doping causes the nucleation and crystallization processes, which then have an impact on the film’s characteristics. It is discovered that the introduction of tungsten metal significantly enhances the quality of the perovskite film, resulting in larger grain sizes, lower band gap energy, and shorter recombination lifetimes, increasing the power conversion efficiency of perovskite thin film solar cells.

Design and Optimization of a Triple‐Cation Perovskite Solar Cell for Efficiency Promotion using Numerical Simulations

AbstractFormamidinium lead iodide (FAPbI3) perovskite has recently gained immense interests as a possible absorber of hybrid halide perovskite (HHP) based solar cells and are extensively investigated both on experimental and theoretical fronts. However, it is unstable against the moisture, making this material domain inappropriate for long run. The compositional engineering i. e., doping in the absorber layer (FAPbI3) of HHP solar cells appears to be very significant for enhancing the stability and overall photovoltaic performance of perovskite solar cells (PSCs). We deal with the numerical simulation and optimization of (GA/FA/Cs)PbI3 based PSC. A diverse set of ETLs and HTLs have been explored to find the optimal combination from 35 device structures. Among them, La‐doped BaSnO3 (LBSO) and CBTS are found to be most appropriate electron/hole transport layers (ETL/HTL) combination for (GA/FA/Cs)PbI3 absorber layer, respectively. In addition, the impact of various parameters such as thickness, defect density, working temperature and back contact work function on the overall device performance have been investigated. After comprehensive optimizations, the proposed PSC demonstrated the superior photovoltaic performance with power conversion efficiency of 24.36 % and fill factor (FF) of 80.17 %. The present simulation work can serve as a benchmark for the fabrication of proposed PSCs.

Two-stage growth of Cu3BiS3 thin films: Influence of the Cu/Bi ratio

Thin films composed of Cu3BiS3 have shown significant promise as light-harvesting materials because of their suitable optoelectronic properties and abundant, non toxic constituent elements. A large-grained, highly crystalline Cu3BiS3 films is a prerequisite for application of these layers in solar cells. We have grown large-grained, highly crystalline Cu3BiS3 films by a two-stage process via thermally evaporating Cu/Bi/Cu metallic layers and sulfurization at 400 °C for 30 min. The influence of the Cu/Bi ratio on the growth of Cu3BiS3 thin films was investigated by varying the Bi precursor thickness. The Cu/Bi ratio significantly influenced the structural, microstructural, optical, and electrical properties of Cu3BiS3 thin films. The Cu3BiS3 film synthesized with a Cu/Bi ratio of 4.35 contained Cu1.8S spurious phase, a non-uniform grain morphology, a direct optical bandgap of 1.41 eV, and an electrical resistivity of 75.5 Ωcm. Upon decreasing the Cu/Bi ratio from 3.38 to 2.77, the Cu1.8S spurious phase was eliminated, and phase-pure Cu3BiS3 was crystallized with a uniform grain morphology, particle size of 2–4 μm, direct bandgap of 1.42 eV, and electrical resistivity of 53.5 Ωcm. A further decrease in the Cu/Bi ratio from 2.77 to 2.54 resulted in a slight decrease in the grain size and electrical resistivity of the Cu3BiS3 films. This study demonstrates that Cu3BiS3 films synthesized with near-stoichiometric composition possess better structural, microstructural, optical, and electrical properties than those synthesized with Cu-rich composition and are suitable for use as solar cell absorber layer.

Scrutinizing the effect of substrate temperature and enhancing the multifunctional attributes of spray deposited copper gallium sulfide (CuGaS2) thin films

ABSTRACT Polycrystalline chalcopyrite CuGaS2 thin films were prepared using a spray pyrolysis route has been considered a potential material for the solar cell absorber layer. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) studied the impact of substrate temperature in the range of 200–300˚C on surface profile and roughness. Powder X-ray diffraction disclosed that the films were polycrystalline at all examined substrate temperatures, with crystallite size increasing with increased substrate temperature. The UV-Vis displays the cut-off wavelength in 550–880 nm for varied substrate temperatures of CuGaS2 thin films, and the observed band gap is 2.75 eV–1.89 eV. The electrical attributes showed the enhancement in mobility (4.632 cm2 V−1 s−1) for varied substrate temperatures of CuGaS2 thin films. The 300˚C temperature sprayed CuGaS2 polycrystalline films are a decent candidate to be apposite as an absorber layer in thin film photovoltaic solar cells.