Thin Film Solar Cells Research Articles

Optical and optoelectrical characterizations of Cu2ZnSn3S8: A potential nominee for optoelectronic and photovoltaic applications

A successful trial has been accomplished in synthesizing a stable phase of Cu2ZnSn3S8 (CZTS8). The deposited thin films have been obtained by utilizing the chemical bath deposition (CBD) process. Basic characterizations have been applied to check the formation of our new stable material. The formed CZTS8 films disclose the amorphous nature as presented in the x-ray diffraction (XRD) patterns. Also, an enhancement in film morphology has been obtained by expanding the film thickness. Moreover, optoelectrical and linear/nonlinear optical features have been studied for the as-deposited films. Our material has interesting characteristics to be a promising window sheet for thin film solar cells. It reveals a tendency to be an n-type semiconductor material. Further, it shows high optical absorption as well as high optical conductivity. Moreover, it has a direct optical transition, and its energy gap is varied in the range (3.89 eV - 3.94 eV). Additionally, the dispersion and optoelectrical indices were affected by the variation in both film thickness and film roughness. Furthermore, the nonlinear optical indices χ(1),χ(3) and n2 were improved via the increase in film thickness. A satisfactory correlation has been performed between all of the evaluated parameters. The main goal of this study has been achieved by obtaining n-type material by increasing the Tin and Sulfur contents in the CZTS8 as compared with the known p-type material (Cu2ZnSnS4) CZTS4. The revealed findings acknowledge that CZTS8 could be a promising nominee for either optoelectronic or photovoltaic applications.

Ternary Ag3AuS2 Nanocrystals for Thin-Film Solar Cells.

The concept of clean and pollution-free energy development has promoted the rise of environmentally friendly silver-based chalcogenide nanocrystal (NC) solar cells, but currently reported silver-based NCs need complex synthesis processes at high temperatures that may bring zerovalent noble metal impurities for their high redox potentials. In this study, we report a facile synthesis of novel Ag3AuS2 NCs by injecting highly active oleylamine sulfur complexes as sulfur sources into metal precursor solutions at low temperatures of 60 °C. The obtained Ag3AuS2 NCs exhibit broad absorption spectra and high molar extinction coefficients (106 M-1 cm-1). Then, the Ag3AuS2 NCs are applied as the light-absorbing active layer in environmentally friendly thin-film solar cells. By introducing a hybrid mixture of charge acceptors and donors (NCs/P3HT hybrid film) at the interface, the device gains an absorption increment and enhanced charge extraction, achieving a final power conversion efficiency of 3.38%. This work demonstrates the enormous potential of Ag3AuS2 NCs from low-temperature preparation for photovoltaic applications.

The Sustainable Development Trend, Progress and Challenge of Solar Cells

The current development of solar cells indicates that this field is experiencing rapid technological progress and market expansion. Various types of solar cells, from traditional silicon-based ones to emerging thin-film, dye-sensitized, perovskite, and organic solar cells, are constantly being developed to improve efficiency, reduce costs, and meet different application needs. While silicon-based solar cells remain one of the most mainstream types on the market, researchers are exploring third-generation photovoltaic devices such as multi-junction series cells, intermediate band gap cells, multiple exciton-generating cells hot carrier cells thermal-light photovoltaic solar cells to further bolster efficiency and reduce costs. These new solar cell technologies theoretically offer higher conversion efficiency and are anticipated to replace traditional silicon-based ones in the future. Advancements in the technology of solar cells mainly involve continuous progress and innovation in materials' development structural design manufacturing processes-from early silicon-based designs to today's thin-film arrays. Each generation is developed with the goal improving efficiency lowering costs; subsequently leading to recent developments in organic and perovskite arrays currently under exploration creating a final product at a lower price. At present, current attention within development primarily lies towards material components advancement efficiency maximization. Cost reduction strategies large scale production Although faced with certain obstacles; through consistent research proving their overwhelming effectiveness; implications for widespread use suggest performance. Overall prospects within Solar energy appear limitless.

High efficiency Sb and Ag double doped Cu2ZnSn(S, Se)4 thin film solar cells realized by post-heat treatment process of heterojunction

Cu2ZnSn (S, Se)4 (CZTSSe) semiconductors have become a recent focus of research owing to their cost-effectiveness, environmental friendliness, and high efficiency. However, insufficient band alignment between the CZTSSe absorption layer and the CdS buffer layer significantly hampers the high conversion efficiency of CZTSSe devices. In this study, problems related to energy-band matching were solved by the post-heat treatment (PHT) of the absorber and buffer layers. Based on obtaining a high-quality absorption layer through double-doped (Cu, Ag)2Zn(Sn, Sb)(S, Se)4 (CAZTSSSe), the impact of the PHT process of CAZTSSSe/CdS on the device performance and heterojunction quality was investigated. The PHT process promoted the reciprocating motion of elements in the heterojunction region, directly inducing the movement of Cd towards the absorption layer and Cu towards the buffer layer. Furthermore, the PHT method enhances the recrystallization of CdS, resulting in the formation of a CdS layer with excellent crystalline quality. After PHT processing, a more favorable conduction band arrangement was obtained, which helps to reduce non-radiative recombination. Ultimately, when the PHT temperature reaches 200 °C, we get an optimal device with an efficiency of up to 9.44 %, as open circuit voltage (VOC) escalates to 431 mV, and lower fill factor (FF) attains 55.63 %. It is believed that this PHT process can be better applied in thin film cells to obtain high-efficiency solar cells.

Tailoring Li assisted CZTSe film growth under controllable selenium partial pressure and solar cells.

It is still critical to prepare a high-quality absorber layer for high-performance Cu2ZnSnSe4 (CZTSe) multi-component thin film solar cell. The gas pressure during the selenization process is commonly referred to as the pressure of inert gas in the tube furnace, while the exact selenium partial pressure is difficult to be controlled. Therefore, the grain growth under different selenium partial pressures cannot be made clear, and the film quality cannot be controlled as well. In this work, we use a sealed quartz tube as the selenization vessel, which can provide a relatively high and controllable selenium partial pressure during the selenization process. To further tailor the grain growth, lithium doping is also utilized. We find that lithium can greatly promote the growth of CZTSe films as the selenium partial pressure is controlled near the selenium saturation vapor pressure. Combined with ALD-Al2O3, the crystallization quality of CZTSe absorber films is significantly enhanced and the efficiency of CZTSe solar cells achieved a significant improvement. This work clarifies the effect of controllable Se pressure on CZTSe film growth and can lead to better results in CZTSe and other multi-compound thin film solar cells.

Application of in-situ synthesized gelidium-like core-shell structure FeCo2S4@NiCo2S4/carbon paper composite on titanium mesh in counter electrode of liquid thin film solar cells

Design inexpensive and stable counter electrodes materials is great essential for accelerating the industrial application of dye-sensitized solar cells. Herein, transition metal sulfides FeCo2S4 and NiCo2S4 were in-situ synthesized into composite with core–shell structure on surface of carbon paper by hydrothermal method, and is used as CEs material of DSSCs. Besides, titanium mesh with lower resistivity is also used as a conductive base to prepare the CEs and reduce the series resistance of DSSCs. Therefore, after electrochemical analysis and photoelectric performance test, it is found that the photoelectric conversion efficiency of the DSSCs assembled with composite material CEs can be as high as 10.08 % (with the Jsc is 19.59 mA·cm−2, Voc is 0.796 V, FF is 0.65), which much higher than traditional Pt CEs (7.99 %) and other corresponding counterparts, indicating that the core–shell structure is more conducive to improving the catalytic activity of the material.

Management of Light Absorption Based on Sidewall Reflection for Fabricating High-Performance Flexible Nano-Coned Sb2Se3 Thin Film Photovoltaics.

High performance and robustness are the key factors to boosting wearable and portable applications. Although the 1D crystal structure makes the Sb2Se3 thin film more tolerant to physical deformation upon bending, the conventional planar structures still cannot undergo repeated mechanical bending due to the induced stress/strain inside devices, which can be well addressed by constructing three-dimensional nanostructures. Besides, the electron diffusion length has two values, 0.3 μm in the [221] direction and 1.7 μm in the [001] direction, in the Sb2Se3 thin film, which limits the absorber thickness, for getting an effective carrier collection; thus, a strong light trapping effect enabling sufficient light harvesting is needed to allow the use of a very thin light absorption layer. Herein, the nanoconed Sb2Se3 solar cells have been designed, and their light absorption behaviors were investigated within a finite-element simulation under the substrate back-reflection, indicating that the reflection of the bottom part always works positively, while the effect of the nanocone sidewall on absorption enhancement largely depends on its geometry, arising from resonant or scattering modes. These results provide a practical guide in designing/establishing an easier/simpler way to fabricate high-performance and mechanically stable flexible nanostructured Sb2Se3 thin film solar cells.

Trends Research Synthesis of TiO2 Thin Films as Solar Cell Materials (2015-2024): A Systematic Review

Research in the field of solar cells continues to increase along with the development of the times and human needs for renewable energy sources. One of the fields of study that is often used as a research topic is the development of Thin Film Solar Cells or known as Thin Film Solar Cells (TFSC). This research aims to identify and analyze research trends of synthesis of TiO2 thin films as solar cell materials. This research method is descriptive and analytical. The data used in this research was obtained from documents indexed by Google Scholar from 2015-2024 using Publish or Perish and Dimension.ai. Research procedures use PRISMA guidelines. The data identified and analyzed are the type of publication, publication source, and the title of research on synthesis of Ti02 thin films as solar cell materials that is widely cited. The data analysis method uses bibliometric analysis assisted by VOS viewer software. The results of the analysis show that research trend on synthesis of TiO2 thin films as solar cell materials indexed by Google Scholar from 2015 to 2024 has experienced increases and decreases. There are many documents in the form of articles, proceedings, chapters, preprints, monograph and edited books that discuss research about synthesis of TiO2 thin films as solar cell materials. Key words that are often used in research about it are dye sensitized cell, electrode, electron, characterization, etc.

Growth temperature-dependent properties of electrodeposited CdSe thin films for optoelectronic application

Cadmium selenide (CdSe) thin films were synthesized using a two-electrode electrodeposition technique in potentiostatic mode. The solution matrix contains 0.3 M Cd(NO3)2.4H2O and 0.03 M SeO2 on conductive glass substrates/fluorine-doped tin oxide (FTO). The electrodeposited CdSe thin films were examined at various growth temperatures of 55, 65, and 85 °C, both as-deposited (AD) and annealed (HT) samples. A polycrystalline cubic structure of the prepared CdSe thin films was identified using x-ray powder diffraction. The energy bandgap of films was found to vary with deposition temperature and was recorded as 1.85, 2.00, and 2.13 eV for AD and 1.86, 2.16 and 2.70 eV for HT samples deposited at 55, 65, and 85 °C, respectively. Surface morphology images show that the form and grain size varied with growth temperature. The average surface roughness varied with deposition temperature. The elemental analysis confirmed that the proportion of cadmium (Cd) increased while that of Se decreased as the deposition temperature increased for both AD and HT films. The film that was deposited at low temperature (55 °C) can be as a layer for absorption. Conversely, however the film deposited at a high growth temperature (85 °C) is capable of serving as a buffer layer in thin-film solar cell technology.

Numerical simulations of novel multi- chalcogenide CuAgBeSnSe4 based thin film solar cell with over 24% efficiency using SCAPS-1D

Abstract For solar cell applications, the multi-chalcogenide CuAgBeSnSe4 (CABTSe) shows promise as a potential absorbing material. In this study, numerical simulations were conducted for the ITO/CABTSe/Ag2S/Au structure, which was screened from a group of 50 CABTSe-based thin film solar cells (TFSCs) using the SCAPS-1D code. We explored the influence of various parameters such as thickness, doping concentration, defect density, mobility, and electron affinity on the photovoltaic performance of the screened device. Under optimized parameters, the open circuit voltage, short circuit current, filling factor, and efficiency of the photovoltaic device were 1.099 V, 25.5 mA/cm2, 86.48%, and 24.24%, respectively. This study provides an effective approach for using CABTSe-based TFSCs as a replacement for traditional Cu2ZnSn(S,Se)4-based TFSCs.

Improving the performance of ZnO/CdS/CZTS thin film solar cell by AMPS-1D numerical tool: effect of the absorber, buffer and window layer parameters

Improving the performance of ZnO/CdS/CZTS thin film solar cell by AMPS-1D numerical tool: effect of the absorber, buffer and window layer parameters

Titanium Nitride as an Alternative Plasmonic Material for Plasmonic Enhancement in Organic Photovoltaics

This paper investigates TiN for its potential to enhance light-harvesting efficiency as an alternative material to Au for nanoscale plasmonic light trapping in thin-film solar cells. Using nanosphere lithography (NSL), plasmonic arrays of both Au and TiN are fabricated and characterized. Later, the fabricated TiN and Au arrays are integrated into a thin-film organic photovoltaic (OPV) device with a PBDB-T:ITIC-M bulk heterojunction (BHJ) active layer. A comparative study between these Au and TiN nanostructured arrays evaluates their fabrication process and plasmonic response, highlighting the advantages and disadvantages of TiN compared to a conventional plasmonic material such as Au. The effect of the fabricated arrays when integrated into an OPV is presented and compared to understand the viability of TiN. As one of the first experimental studies utilizing TiN arrays for the plasmonic enhancement of photovoltaics, the results offer valuable insight that can guide future applications and decisions in design.

Performance analysis and optimization of SnSe thin-film solar cell with Cu2O HTL through a combination of SCAPS-1D and machine learning approaches

Tin selenide (SnSe) is an auspicious light-harvesting material in photovoltaic (PV) technology due to its larger absorption coefficients and earth-abundance nature. However, because of the potential difficulty of defect-free fabrication, and non-optimized electron transport layer (ETL) and hole transport layer (HTL) alignment, it could no longer achieve its realistic objectives. Therefore, designing a suitable SnSe-based PV device with an appropriate ETL and HTL is crucial to achieving optimum performance. In this research, we proposed a novel heterojunction thin-film solar cell (TFSC) configuration of Ni/Cu2O/SnSe/WS2/FTO/Al and simulated its PV performance metrics using SCAPS-1D solar cell simulation software. This research additionally provided a comparative performance analysis of the SnSe TFSC with numerous ETLs and HTLs. It is evident that the suggested TFSC with WS2 ETL and Cu2O HTL creates appropriate band alignment with the SnSe light harvesting layer, which reduces charge recombination at both the ETL/absorber and absorber/HTL interfaces. Here, the impact of absorber layer thickness, doping concentration, bulk defect density, and defect density at the ETL/absorber and absorber/HTL interfaces is investigated. Besides, the impact of radiative recombination, back contact metal work function, and working temperature are carefully examined. After optimization of all the material properties, a maximum efficiency of 29.31 % with open circuit voltage (Voc) of 0.89 V, short circuit current density (Jsc) of 38.23 mA/cm2, and fill-factor (FF) of 86.30 % were attained for the SnSe-based proposed structure. Furthermore, a supervised linear regression machine learning algorithm is employed to investigate how the behavior of the material attributes affects the solar cell's designed PV performance. Overall, our findings can be helpful to experimentalists to fabricate inexpensive, highly efficient, and Cd-free SnSe-based heterostructure solar cells in the near future.

Formation of High-Photoresponsivity BaSi2 Films by Radio-Frequency Sputtering and Evaluation of a BaSi2/TiN/Glass Heterojunction by Transmission Electron Microscopy.

Barium disilicide (BaSi2) is a thin-film solar cell material composed of abundant elements, and its application potential is further enhanced by its formation on inexpensive substrates, such as glass. The effect of the substrate temperature on the co-sputtering of BaSi2 and Ba targets to form BaSi2 films on Si(111) and TiN/glass substrates was investigated. Contrary to expectations, the photoresponsivity reached maximum values exceeding 5 and 2 A W-1, respectively, the highest value ever reported for as-deposited samples formed at 750 °C, more than 100 °C higher than those reported previously. Because the photoresponsivity is proportional to carrier lifetime, this result indicates that high-temperature growth can bring out the high performance of BaSi2 as a light-absorbing layer. Because amorphous SiC (a-SiC) has a larger forbidden band gap and electron affinity than BaSi2, it is considered suitable as an electron transport layer (ETL) material for BaSi2 solar cells. On the basis of this, the formation of BaSi2 (absorption layer)/a-SiC (ETL)/TiN (electrode)/glass heterojunctions was also attempted, and the layered structure was examined by cross-sectional transmission electron microscopy (TEM). Polycrystalline BaSi2 films were found to be even on the amorphous layer by TEM. A high photoresponsivity of over 2 A W-1 was obtained. Therefore, the BaSi2/a-SiC/TiN structure provides a guideline for the structural design of BaSi2-based thin-film solar cells on glass.

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.

Theoretical Optimization of an Earth-Abundant and Environmentally Friendly Photovoltaic Absorber Cu3PSe4 from First-Principles Study to Device Simulation.

To seek an earth-abundant and environmentally friendly absorber for thin-film solar cells, Cu3PSe4 is investigated by first-principles calculations and device simulations. We demonstrate that the compound has a suitable band gap width of 1.3 eV as well as a high sunlight absorption coefficient. However, drawbacks like small electron affinity, high hole concentration, large lattice mismatch with CdS, etc., are revealed, which may degrade the photovoltaic performance. To address those shortcomings, we propose (1) to optimize the carrier concentration by preparing the samples at low temperature and under a Cu-rich environment, (2) to replace the CdS buffer layer by a more suitable wide-gap semiconductor with smaller lattice mismatch, and (3) that the selected buffer layer should have small electron affinity in order to reduce the open-circuit voltage losses. After implementation of these optimization approaches, the device simulations demonstrate that the power conversion efficiency reaches 17.7% for a solar cell with the configuration Mo/Cu3PSe4/WS2/n-ZnO. The combination of first-principles calculations at the atomistic level and device simulations at the macroscopic level provides an appropriate approach to design ideal solar cells.

Enhanced Design of Kesterite Solar Cells through High-Throughput Screening and Machine Learning Approaches.

Kesterite Cu2ZnSnS4 (CZTS) is regarded as one of the most promising materials for thin-film solar cells due to its high light absorption capability, composition of earth-abundant and nontoxic elements, and ease of low-cost mass production. Although the certified power conversion efficiency (PCE) of kesterite solar cells has exceeded 14%, this efficiency remains significantly below the Shockley-Queisser limit. In this study, we generated a Perdew-Burke-Ernzerhof (PBE) band gap data set encompassing 263 64-atom species for high-throughput screening by substituting elements at different sites in A2BCX4 quaternary kesterite materials. Additionally, we utilized a symbolic regression method based on genetic programming to explore the functional relationship among the oxidation state, ionic radius, and electronegativity of kesterites with PBE band gaps. Simultaneously, we employed decision tree models (XGBoost, LightGBM, CatBoost, and random forest) and convolutional neural network (CNN) models (CustomCNN, VGG16, DenseNet121, Xception, and EfficientNetV2B0) to predict band gaps, achieving a coefficient of determination (R2) of up to 0.93. Furthermore, we selected 54 kesterite materials with PBE band gaps ranging from 0.4 to 1.5 eV for detailed electronic structure calculations with Heyd-Scuseria-Ernzerhof (HSE06) functional and investigated the effects of B-site atomic substitutions on the performance of solar cell materials. Compared to Ag2CaSnSe4, Ag2SrSnSe4 exhibits fewer deep defects and richer shallow defects, which contribute to an increased carrier concentration and reduced charge and energy losses, making it a superior candidate for solar cell applications.

An electro-thermal finite element method (FEM) model for local hotspot kinetics in Cu(In, Ga)Se2 thin-film solar modules

Partial shading can significantly impair the efficiency of thin-film solar cells. When exposed to partial shading, cells within the array tend to become reverse biased, leading to thermal runaway events and the emergence of hotspots. In Cu(In,Ga)Se2 (CIGS) solar cells such hotspots are also associated with so-called worm-like defects. Both theoretical and experimental studies have shown that in CIGS, a positive-feedback loop leads to instability and thermal runaway events. However, we observe an inconsistency between published simulation results and recently published experimental work. In a recent experimental study, it was shown that under certain conditions, a hotspot develops within 1ms, showing signs of melting of the CIGS in an area with a 5μm radius. However, in published simulation results, the time for such high temperatures to develop is in the order of seconds, a discrepancy of three orders of magnitude. In this work, we argue that this discrepancy is explained by the size of the seed defect, demonstrating that the origin of these experimentally observed, fast-developing hotspots is likely microscopic defects. To this end, we developed an electro-thermal finite element model, with very high temporal and spatial resolution. We demonstrate that, assuming a seed defect with a 10nm radius, we can reproduce the experimental results with respect to the size of the defect and the time it took to develop.

Performance Enhancement of SnS Solar Cell with Tungsten Disulfide Electron Transport Layer and Molybdenum Trioxide Hole Transport Layer

Herein, a new heterojunction photovoltaic (PV) device is designed by incorporating molybdenum trioxide (MoO3) as a hole transport layer (HTL), tin sulfide (SnS) as an absorber, and tungsten disulfide (WS2) as an electron transport layer (ETL). The PV outputs of the proposed thin‐film solar cell (TFSC) of Ni/MoO3/SnS/WS2/FTO/Al are investigated using the widely used solar cell simulator (SCAPS‐1D). It is found that the SnS TFSC with suitable band alignments at both the SnS/WS2 and MoO3/SnS interfaces gives better photoconversion efficiency than the conventional one. To optimize the material properties, the performance parameters, including open‐circuit voltage (Voc), short‐circuit current density (Jsc), fill factor (FF), and efficiency, have been calculated by varying the influences of the material's thickness, doping concentration, bulk and interface defect densities, operational temperature, and work function of back‐contact. At optimized thicknesses of 0.1 μm for MoO3 HTL and 1.0 μm for SnS absorber, the efficiency is estimated to be 30.42% with Voc of 1.02 V, Jsc of 34.38 mA cm−2, and FF of 87.04% for the suggested TFSC. These outcomes imply that the nontoxic MoO3 and WS2 materials can be applied as HTL and ETL into the inexpensive, highly efficient, and environmentally friendly SnS‐based PV cell.

Interplay between strain and charge in Cu(In,Ga)Se2 flexible photovoltaics

Flexible and lightweight Cu(In,Ga)Se2 (CIGS) thin-film solar cells are promising for versatile applications, but there is limited understanding of stress-induced changes. In this study, the charge carrier generation and trapping behavior under mechanical stress was investigated using flexible CIGS thin-film solar cells with various alkali treatments. Surface current at the CIGS surface decreased by convex bending, which occurs less with the incorporation of alkali metals. The formation energy of the carrier generating defects increased in convex bending environments clarifying the degradation of the surface current. Moreover, alkali-related defects had lower formation energy than the intrinsic acceptors, mitigating current degradation in mechanical stress condition. The altered defect energy levels were attributed to the deformation of the crystal structure under bending states. This study provides insights into the mitigating of strain-induced charge degradation for enhancing the performance and robustness of flexible CIGS photovoltaic devices.