Absorber Layer In Solar Cells Research Articles

Enhanced optoelectronic characteristics of La-doped ZnO and its compatibility with Cs-doped MAPbI3 perovskite absorber material

Abstract The present study investigates the structural, electrical and optical characteristics of pristine and lanthanum (La)-doped zinc oxide electron transport layers (ETLs) fabricated by the sol gel method and their compatibility with Cs0.10MA0.90Pb(I0.9Br0.10)3 absorber layer for perovskite solar cells. All the ETLs were deposited under same deposition conditions, with the only difference in La percentage in the precursor solutions, ranging from 0 to 6%. X-ray diffraction (XRD) analysis demonstrated the presence of crystalline ZnO thin films and the absence of any impurity phases after La-doping. The calculated crystallite size, determined using Scherrer’s equation, increased from 11.13 to 21.76 nm after the introduction of dopant. The doping with 4% La led to the decrease in the optical bandgap from 3.32 eV of pristine ZnO to 3.23 eV. SEM analysis revealed better morphology of perovskite/4% La:ZnO specimen, which facilitated the absorbance and reduced the charge carrier recombination. It also exhibited superior resilience towards moisture and humidity which will eventually contribute to the development of more stable and efficient planar perovskite solar cells (PCSs).

Comprehensive evaluation of mechanical properties, optoelectronic features, photovoltaic performance, and crystal stability of Ba3MX3 (M = As, Sb; X = Cl, Br, I)

Herein, the first-principles computations are utilized to study the optoelectronic properties, photovoltaic performance, crystal stability, and mechanical features of Ba3MX3 (M = As, Sb; X = Cl, Br, I). Through comprehensive structural stability evaluation, all compounds are determined to be stable. The results indicate that Ba3MX3 (M = As, Sb; X = Cl, Br) is brittle while both Ba3AsI3 and Ba3SbI3 are ductile. The HSE06-based electronic structure calculations show that the direct-gap nature is revealed for six compounds, and the energy band gaps are within the range of 1.35–1.65 eV. The fundamental band gap can be modulated by virtue of X-anion substitution. The low carrier effective masses are disclosed for these compounds. Their optical features exhibit that high solar absorption and weak reflectance and energy loss are observed. Ultimately, an ultra-high theoretical conversion efficiency of 31.9 % is implemented for Ba3MI3 (M = As, Sb). Besides, the remaining four compounds also have high conversion efficiencies within 29–30 %. From the suitability for practical applications, both Ba3AsI3 and Ba3SbI3 are chosen as the best candidates for the absorber layers of effective single-junction solar cells. Our findings unveil the suitability of these inorganic materials for optoelectronic applications.

11.88% Efficient Flexible Ag-Free CZTSSe Solar Cell: Spontaneously Tailoring the Alkali Metal Level.

Alkali metal is the requirement for highly efficient Cu2ZnSn(S, Se)4 (CZTSSe) solar cells, thus it is crucial to additionally incorporate alkali metal into the absorber layer for flexible solar cells. However, the efficiency of flexible CZTSSe devices reported to date, based on the conventional alkali incorporation strategies, still lags behind those made on rigid substrates. One of the main issues is the inability to control the alkali content and distribution in the absorber layer. Here, a facile alkaline incorporation approach is proposed, effectively regulating the content and distribution of alkali metals in the film. Such a method can spontaneously tailor the alkali metal content to a proper level, thus leading to the suppression of non-radiative recombination and a better carrier transport through the enhanced film quality and the optimized band binding structure. Finally, a champion flexible CZTSSe solar cell with an efficiency of 11.88% is achieved, the highest reported efficiency for a CZTSSe solar cell without noble Ag doping. This study affords an innovative spontaneous alkali-doping design for the preparation of high-performance flexible CZTSSe solar cells and provides a deeper insight into the extent of alkali metal doping.

A Broadband Light‐Trapping Nanostructure for InGaP/GaAs Dual‐Junction Solar Cells Using Nanosphere Lithography‐Assisted Chemical Etching

III–V‐based multijunction solar cells have become the leading power generation technology for space applications due to their high power conversion efficiency and reliable performance in extraterrestrial environments. Thinning down the absorber layers of multijunction solar cells can considerably reduce the production cost and improve their radiation hardness. Recent advances in ultrathin GaAs single‐junction solar cells suggest the development of light‐trapping nanostructures to increase light absorption in optically thin layers within III–V‐based multijunction solar cells. Herein, a novel and highly scalable nanosphere lithography‐assisted chemical etching method to fabricate light‐trapping nanostructures in InGaP/GaAs dual‐junction solar cells is studied. Numerical models show that integrating the nanostructured Al2O3/Ag rear mirror significantly enhances the broadband absorption within the GaAs bottom cell. Results demonstrate that the light‐trapping nanostructures effectively increase the short‐circuit current density in GaAs bottom cells from 14.04 to 15.06 mA cm−2. The simulated nanostructured InGaP/GaAs dual‐junction structure shows improved current matching between the GaAs bottom cell and the InGaP top cell, resulting in 1.12x higher power conversion efficiency. These findings highlight the potential of light‐trapping nanostructures to improve the performance of III‐V‐based multijunction photovoltaic systems, particularly for high‐efficiency applications in space.

Investigation of thermally induced surface composition and morphology variation of magnetron sputtered Sb2Se3 absorber layer for thin film solar cells

One of the most promising semiconductor materials for the development of sustainable thin-film solar cell technology is antimony selenide (Sb2Se3). Its excellent optical and electrical properties have drawn attention lately for potential application in thin-film solar cells. In this study, Sb2Se3 films deposited using the direct current (DC) magnetron sputtering technique have been subjected to a post-annealing process without an extra selenium supply at temperatures between 150 and 450 °C. Without an extra selenium supply, the impact of post-annealing temperature on the surface composition as well as the physical properties of the fabricated films was investigated. The overall evaluations revealed that the post-annealing temperature is highly efficient in altering the physical properties of the Sb2Se3 absorber thin films. We further observed that the post-annealing process improved the crystallization and the heat treatment temperature quite affected preferential orientation. The surface morphology of films exhibited structural deformation at high post-annealing temperatures (> 350 °C). According to optical and electrical characterizations, respectively, the optical energy gap and the resistivity of Sb2Se3 films reduced with an increment in the post-annealing temperature. Based on the XPS result, the variation in temperature of post-annealing led to a change in the surface composition of the films. The findings on the growth of Sb2Se3 thin films indicate the existence of an intermediate growth temperature that permits the growth of Sb2Se3 films to be optimized. The study’s conclusions can serve as a guide to the growth of Sb2Se3 thin films with the desired crystallinity, surface morphology, and composition for thin film solar cell applications.

Unveiling the potential of FASnI3 solar cells through advanced charge transport materials: A SCAPS-1D perspective

As demand grows for efficient and affordable photovoltaic technology, investigating alternative materials becomes crucial. Tin-based perovskite has a low bandgap, great optoelectronic properties, and higher carrier mobility. It has become an interesting absorber layer for perovskite solar cells (PSCs). However, improving their device performance presents challenges. Copper-based hole transport materials (HTM) and zinc-based electron transport materials (ETM) offer low cost, easy fabrication, and high electrical conductivity. This research analyzes the impacts of these transport materials on the FASnI3 absorber layer using numerical modeling in SCAPS-1D. Through simulation analysis, the study thoroughly examines the effect of these materials on PSC performance parameters such as QE curve, layer thickness, defect density, interface defect, and doping concentration. Moreover, this study identifies the most efficient PSC configurations, achieving good performance by ITO/ZnSe/FASnI3/Cu2O/Au with aVoc of 2.05 V, Jsc of 29.316 mA/cm2, FF of 53.37 %, and power conversion efficiency (PCE) of 32.13 %, providing valuable insights in optimizing FASnI3 solar cells and advancing next-generation solar energy conversion technologies.

Effect of carrier gas on copper antimony sulfide thin films by spray pyrolytic approach

This study explores the ternary compound semiconductor as a potential absorber layer for third-generation solar cells. CuSbS2, a promising candidate for thin film absorber layers, is fabricated using a simple spray pyrolysis method. The research specifically investigates the influence of two different carrier gases during the fabrication process. X-ray diffraction as well as Raman studies confirm that the films exhibit a chalcostibite structure. Notably, films fabricated with nitrogen as the carrier gas demonstrate enhanced crystallinity, accompanied by reduced microstrain and dislocation density. Furthermore, these films exhibit a significantly improved absorption coefficient, reaching 105 cm-1 . Optical studies indicate that the materials possess a direct band gap of 1.50 eV and exhibit p-type conductivity. CuSbS2 thin film heterojunction solar cell exhibits a maximum efficiency of 0.49%.

Effect of Sb2S3 sacrificial layer thickness on structural, optical and electrical properties of CuSbS2 films and investigation of diode parameters of CuSbS2/CdS heterojunctions

The ternary copper chalcogenides CuSbS2 (CAS) is found to have appealing optical and photovoltaic properties to be used as absorber layer in thin film solar cells. However, the difficulty to grow good quality CuSbS2 layer of micrometer thickness by chemical bath deposition method holds a big challenge. In this work, we reported the effect of incorporating Sb2S3 sacrificial layer of different thickness on structural, optical and electrical properties of CAS films. The X-ray diffraction results and Raman spectroscopic analysis confirm the formation of single-phase orthorhombic crystal structure for CuSbS2. The increase of Sb content in CAS films with the increase in deposition time of Sb2S3 layer has been reflected in the change in relative intensity ratio of characteristic Raman peaks as well as in diffraction peak profiles. The magnitude of defect states in terms of Urbach energy is decreased drastically by increasing Sb percentage in the films. A clear improvement in electrical properties of CAS films is observed with the decrease in Cu/Sb ratio. The carrier density is increased by one order of magnitude from 1016 to 1017 cm−3 and hole mobility increases from 1.14 to 4.87 cm2/Vs. The impact of Sb concentration on Scottky diode parameters of CAS/CdS heterojunction was studied by using thermionic emission model. Both the ideality factor and series resistance are decreased with the increase in Sb content. The J-V measurements reveal that the integration of Sb2S3 sacrificial layer improves the PV parameters such as fill factor, open circuit voltage, photocurrent and efficiency. The overall improvement in diode parameters can be ascribed to decrease in defect states, better film quality, absorber layer thickness and improved stoichiometry of CAS films.

Exploring the potential of CsPbI3/CsPbBr3 heterojunction as an absorber layer in perovskite solar cells: a numerical and experimental study

Exploring the potential of CsPbI3/CsPbBr3 heterojunction as an absorber layer in perovskite solar cells: a numerical and experimental study

Thickness variation on some physical properties of CdS: MgO films

In this study, CdS: MgO films were synthesized using the chemical spray pyrolysis method, varying the film thickness. X-ray diffraction (XRD) analysis confirmed the polycrystalline nature of the films, with an observed increase in average crystallite size corresponding to thicker films, and The films' surface morphology indicates an absence of crystal defects such as holes and voids . The investigation of energy gap and optical parameters revealed a dependency on film thickness, with the energy gap shifting from 2.412 eV for a thickness of 150 nm to 2.354 eV for a thickness of 750 nm. Hall effect measurements demonstrated an augmentation in carrier concentration with increasing film thickness. The findings suggest a substantial influence of thickness on the physical properties of CdS: MgO thin films. Notably, thicker films exhibit characteristics that make them promising candidates for application as absorber layers in solar cells. This research provides valuable insights into tailoring the properties of these films for optimal performance in solar energy conversion devices, emphasizing the importance of controlling thickness in achieving desired electronic and optical characteristics.

Preparation of CuSe nanoparticles by antisolvent process for doping and passivation of absorber layer in CdTe solar cells

The p-type doping and passivation of the back surface of the CdTe absorber layer are two key steps to enhance the performance of CdTe thin film solar cells. In recent years, different Cu-doped precursors (Cu (I) and Cu (II) materials) and passivation materials (elements such as Se, Cl, Al, etc.) have been investigated. However, few researchers have proposed in new materials on both doping and passivation functions for backside applications. Here, CuSe, which combines the potential of p-type doping and Se passivation functions, is proposed for the first time as a doping precursor for the CdTe absorber layer. A certain amount of CuSe nanoparticles was deposited on the back surface of the CdTe absorber layer based on an antisolvent deposition process. The results show that the optimal device open-circuit voltage of the CuSe-treated CdTe solar cell reaches 842.5 mV, which is ∼ 6.5 % higher than that of the CuCl2-treated CdTe device (791.4 mV). The results of current-voltage and Mott-Schottky, impedance spectrum show that the CuSe-treated CdTe device not only achieves the purpose of p-type doping, but also introduces the passivation function of Se.

Numerical Optimization of Thickness and Optical Band Gap of Absorber and Buffer Layers in Earth-Abundant Cu2ZnSnS4 Thin-Film Solar Cells

Numerical Optimization of Thickness and Optical Band Gap of Absorber and Buffer Layers in Earth-Abundant Cu2ZnSnS4 Thin-Film Solar Cells

Enhancing CsSn0.5Ge0.5I3 Perovskite Solar Cell Performance via Cu2O Hole Transport Layer Integration

Perovskite solar cells (PSCs) have emerged as a promising alternative to traditional silicon solar cells due to their low cost of fabrication and high power conversion efficiency (PCE). The utilization of lead halide perovskites as absorber layers in perovskite solar cells has been impeded by two major issues: lead poisoning and stability concerns. These hindrances have greatly impeded the industrialization of this cutting-edge technology. In light of the harmful effects of lead in perovskite solar cells, researchers have shifted their attention to exploring lead-free metal halide perovskites. However, the present alternatives to lead-based perovskite exhibit poor performance, thus prompting further inquiry into this matter. The primary objective of this research is to investigate the use of Cu2O as a hole transport layer in combination with lead-free metal halide perovskite (CsSn0.5Ge0.5I3) to achieve superior performance. Through meticulous experimentation, the suggested model has achieved outstanding results by optimizing several key variables. These variables include the thickness of the absorber layer (CsSn0.5Ge0.5I3), defect density, and doping densities, as well as the back contact work function and the operating temperature associated with each layer. The proposed FTO/PC60BM/CsSn0.5Ge0.5I3/Cu2O/Au solar cell structure surpassed prior configurations by comprehensively examining key aspects such as absorber layer thickness and defect density, doping densities, and back contact work. The structure has been also compared with multiple electron transport elements and concluded that the proposed model functions superior due to the use of PC60BM as an electron transport layer and it has an improved electron extraction procedure. Finally, the proposed model has achieved the optimized values as Jsc of 31.56 mA/cm-2, Voc of 1.12 V, FF of 81.47%, and PCE of 27.72%. As a consequence of this research, the investigated structure may be an excellent contender for the eventual creation of lead-free solar power cells made from perovskite.

First-principles study of the structural, mechanical, electronic, optical, and elastic properties of non-toxic XGeBr3 (X=K, Rb, and Cs) perovskite for optoelectronic and radiation sensing applications

In this study, a comprehensive analysis of the structural, electronic, optical, and elastic properties of cubic perovskite structure XGeBr3(X=K,Rb,andCs) was carried out using GGA-PBE functional based density functional theory in CASTEP code. The simulated values of the lattice parameter were increased with the changing of X from K to Cs (a = 5.51 Å, 5.54 Å, and 5.59 Å respectively). All the compounds possessed direct band gaps and acquired values for the structures KGeBr3, RbGeBr3 and CsGeBr3 were 0.525 eV, 0.599 eV, and 0.708 eV, respectively. Furthermore, the atomic orbital's contribution to the formation of band structure was clarified thoroughly. The thermodynamic, as well as the mechanical stability, has been accomplished with the assurance of negative formation energy and Born-Huang approximation. In addition, a larger shearing modulus attained by CsGeBr3 manifests its strength. Moreover, all structures bear the proof of having ductility and existing central force inside the structures. Finally, the calculated anisotropic index notifies that all structures exhibit anisotropy with the trend of CsGeBr3 < RbGeBr3 < KGeBr3. This is also authenticated through the 3D anisotropy contour plot generated by utilizing ELATE software, which is for the first time in regard to the comparative scenario among them. With the investigation of the optical characteristics of the compounds XGeBr3, intriguing features such as broad absorption spectrum, high dielectric function and refractive index at zero photon's energy, and high conductivity have been affirmed accompanying the marginal value of loss function as well as reflectivity that elevates the probability of being employed in optoelectronic applications along with different absorber layers of tandem solar cells. In addition, these compounds could be used as radiation detectors since they have broad absorption at extreme ultraviolet rays.

Synthesis and characterization of CZTS and Cu2-xAgxZnSnS4 thin films for the application of solar cells

We report on colloidal Cu2ZnSnS4 (CZTS) and Cu2-xAgxZnSnS4 (X=0.25) nanoparticles synthesis by sol-gel spin coating process and hot injection method. The colloidal nanoparticles were deposited on ITO substrates by using spin-coating techniques. The deposited thin films were characterized by X-ray diffraction (XRD), UV-visible spectrometer, FE-SEM, Raman spectroscopy and Keithley 2450 Source meter. XRD reveals that the crystal structure of CZTS is confirmed tetragonal structure with peak (112) and observed the changes to wurtzite peak (002) due to the presence of Ag. UV visible spectra show that the optical band gap of CZTS nanoparticles decreases from 2 eV to around 1.75 eV, and there is a significant improvement in absorption coefficient when the sample is prepared under a nitrogen atmosphere. FESEM captured the microstructure image of CZTS and Cu2-xAgxZnSnS4. Photoluminescence (PL) reveals the emission peaks and Raman spectra investigate the secondary phases present. XPS confirms the presence of each element and their oxidation state. Further, electrical properties are studied using the four-probe method at room temperature. CZTS offers optical and electrical properties, which allow it to be suitable for thin-film solar cell absorber layers, and Ag doping enhances its properties.

Effect of defect density, bandgap profile, material composition, thickness, and doping density of the absorber layer on the performance of thin film solar cell based on antimony selenosulfide Sb2(Se1-ySy)3

This article deals with the optimization by simulation of a graded bandgap thin film solar cell based on antimony selenosulfide Sb2(Se1-ySy)3 having the following structure: Front contact/n-ZnO/i-ZnO/p-SbSSe/n-CdS/Back contact. The simulation is performed using SCAPS-1D software. The optimization process includes optimizing the bulk defect density, bandgap profile, material composition, thickness, and doping density of the absorber layer of thin film solar cell based on antimony selenosulfide Sb2(Se1-ySy)3. We found that for a bulk defect density below 1013 cm-3 , using an absorber material with a graded bandgap profile leads to an efficiency of 25.33 % (For a bulk defect density of 1010 cm-3 ) higher than that with a uniform bandgap profile. However, for a bulk defect density of 1013 cm-3 , both profiles provide almost the same maximum solar cell conversion efficiencies of about 13.6 %. Ultimately, for a bulk defect density above 1013 cm-3 , the graded bandgap profile is not useful, and a maximum solar cell conversion efficiency of 10.5 % (For a bulk defect density of 1014 cm-3 ) is achieved with a uniform bandgap profile. These optimization results help to improve the efficiency of low-cost fabricated thin-film solar cells.

Production and Characterization of Electrodeposited Cadmium Sulfide Semiconductor Films with Different Boron Content

AbstractIn this study, Cadmium Sulfide (CdS) semiconductor films are electrodeposited on Indium Tin Oxide (ITO) substrates at 80 °C base temperature for different boric acid (H3BO3) ratios. The effect of boric acid on these films is investigated. For this, first of all, the structural change of the films is examined. Among the films obtained with different boric acid ratios, the optimum film is achieved with 0.06 m boric acid doped. From the basic absorption spectra (αhʋ) of the obtained CdS:B films, the variation of hʋ is drawn and it is determined that the CdS:B semiconductor films has a direct band transition. From the basic absorption spectra of the obtained CdS:B films, it is observed that the CdS:B semiconductor films has a direct band transition. In addition, the optical energy bandgap values obtained are in agreement with the values in the available literatures. The results of the structural, optical, and morphological properties of the films produced in this study indicate that among the selected additive ratios, 1% boric acid gives the best and optimum deposition condition. The thin films obtained are also found to be useful as absorber layers in photovoltaic solar cells.

Influence of Supplementary Oxide Layer on Solar Cell Performance

The increasing use of solar energy for electricity production has led to a directly proportional growth in the production of solar cells. Photovoltaic (PV) performance of silicon solar cells can be improved by using more efficient technologies, optimizing processes, and changing behavior in order to reduce operational costs and greenhouse gas emissions. In order to propose solutions for commercial solar cell production with better performance, this article presents an experimental assessment on Supplementary Oxide Layers (SOLs) that are deposited on the surface of a solar cell absorber layer. SOLs are typically used to improve the performance of solar cells by passivating surface defects, reducing recombination losses, and improving the electrical contact between the absorber layer and the metal electrodes. The obtained solar cells are tested under natural sunlight conditions, following a variable dynamic electronic charge profile. The experimental results along with the corresponding I-V and P-V curves, are assessed according to the process parameters, the lighting parameters, and the dynamic load scenario. SOLs have been shown to improve the Power Conversion Efficiency (PCE) of solar cells considerably. The proposed method for increasing the energy efficiency of solar cells can be applied to any type of commercial solar cell and it is easy to implement at the industrial or research level by controlling process parameters. The integration of the whole process, i.e. development of precursor solutions, deposition of thin films, and testing of electrical properties is another contribution of the current study, along with its interdisciplinary character, which involves materials science, electronics, and software programming.

Numerical investigation of CuSbS2 thin film solar cell using SCAPS-1D: enhancement of efficiency on experimental films by defect studies

The study of photovoltaic solar cells has been an exciting field of research because of their environmentally friendly nature. Scientists are continuously searching for new methods to develop solar cells that are highly efficient and cost-effective. One promising option is the use of Copper Antimony Sulphide (CuSbS2) based ternary compound semiconductor in ultrathin film photovoltaic cells. This material has a high absorption coefficient, low cost, and is readily available in the earth’s crust. These characteristics make it an ideal candidate for use as a thin-film absorber layer in solar cells. In this work, FTO/CdS/In2S3/CuSbS2/Spiro-OMeTAD/Au device is proposed to improve the efficiency of experimentally designed CuSbS2-based thin film solar cells using numerical modeling. Device simulation was carried out using SCAPS-1D software, and the illumination spectrum used for this optimization was 1.5 AM. The simulated results from SCAPS-1D were compared to the experimental data. After optimizing the device parameters all the electrical parameters of the solar cell were improved. The optimized CuSbS2-based device shows power conversion efficiency (PCE) of 21.11% with short circuit current density (Jsc) of 20.96 mA cm−2, open circuit voltage (Voc) of 1.23 V, and fill factor (FF) of 81.84%. Based on the simulation results, it is possible to increase the performance of the device by varying different parameters such as the defect density of each layer, interfacial defect density, thickness, and doping concentration.

Enhancing the properties of Cd-free MgZnS buffer for solar cells by co-sputtering ZnS and Mg targets

The buffer is an essential component that connects the window and absorber layers in thin film solar cells, which has significant impacts on the performance of cell device. CdS is widely used buffer material, but it has drawbacks of toxicity and narrow band gap of 2.4 eV. This work explores the fabrication of a novel Cd-free MgZnS buffer layer through co-sputtering ZnS and Mg targets. The grain size, morphology, phase composition, transmittance and band gap of MgZnS films are manipulated by adjusting the substrate temperature, sputtering power of ZnS target and sputtering current of Mg target. The MgZnS film exhibits remarkable characteristics, including high crystallinity with grain size of about 35 nm, high transmittance of over 80%, and high band gap of 3.44 eV. The process parameters with favorable outcomes include substrate temperature of 300 °C, ZnS sputtering power of 100 W, and Mg sputtering current of 0.05 A. Furthermore, compared with the CdS buffer, the MgZnS buffer has better compactness and transmittance. This method provides a promising new and effective avenue to fabricate Cd-free buffers for solar cells.