Fabrication Of Solar Cells Research Articles

Comparison of different approaches to texturing monocrystalline silicon wafers for solar cell applications

Texturing the surface of crystalline silicon wafers is a very important step in the production of high-efficiency solar cells. Alkaline texturing creates pyramids on the silicon surface, lowering surface reflectivity and improving light trapping in solar cells. This article provides a comparative evaluation of various wet texturing methods using alkaline solutions with or without additives commonly known as surfactants. One method uses sodium hydroxide (NaOH) and isopropyl alcohol (IPA) to create a surface with a height of about 4.5 μm by texturing for about 30 min, while the other method uses potassium hydroxide (KOH) and other additions known as additives. Texturing was performed using chemicals for only 15 min to create a surface shape with a height of approximately 3.5 μm. Additionally, the two solutions showed reflectance of 8.01 % or 12.1 % in 400–1100 nm, respectively. Both processes used alkaline etching at 80 °C for saw damage removal (SDR) before texturing. These processes have also been investigated in terms of removing potential organic contaminants from surfaces. Characterization techniques used throughout the investigation included optical microscopy, surface reflectance measurements, scanning electron microscopy (SEM), and electron dispersive spectroscopy (EDS). The purpose of this study is to confirm through experiments which texturing techniques are more suitable for mass production and to develop time- and cost-effective texturing techniques for industrial production of high-throughput, high-efficiency solar cells.

Synthesis of conjugated structural copolymer poly(3-hexylthiophene-random-benzoyl dithieno[3,2-b:2’,3’-d]pyrrole) by electrochemical method

Electrochemical copolymer synthesis of benzoyl dithieno[3,2-b:2’,3’-d]pyrrole and 3-hexylthiophene (3HT) promises to create new polymer with suitable improved HOMO and LUMO with the energy level of acceptor compounds such as Fullerene (C60) or the novel accepted organic compound in the heterojunction in organic solar cell. Electrochemical synthesis of copolymer (3-hexylthiophene-random-benzoylbdithieno[3,2-b:2’,3’-d]pyrrole by linear potential scanning method was studied and applied for synthesis of conjugated copolymer where three electrodes have been used for polymerisation including the working electrode of Indium Tin Oxide (ITO) substrate, the reference electrode of Ag/AgCl in saturated KCl and the counter electrode of platinum wire. The synthesised copolymer was characterised and evaluated through an electrochemical process, Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and ultraviolet-visible spectroscopy (UV-Vis) measurements. The synthesised copolymer has a bandgap of 2.09 eV, HOMO and LUMO energy levels of -5.21 and -3.12 eV, respectively. The HOMO-LUMO of the synthesised conjugated copolymer is closed with the HOMO-LUMO of Fullerene; therefore, the conjugated copolymer is a potential material for the fabrication of organic solar cell.

Nanosecond laser-induced crystallization of SiOx/Au bilayers in air and vacuum

High-quality polycrystalline silicon films on low-cost and low-temperature substrates have attracted much attention as promising materials for high-speed thin-film transistors and thin-film solar cells fabrication. To obtain poly-Si films on low temperature substrates, several concepts have been proposed. Usually the amorphous material undergoes crystallization which can be achieved by various methods including solid-phase crystallization, metal-induced crystallization or liquid-phase crystallization. In this work, we tried to combine the advantages of metal-induced crystallization and liquid-phase crystallization. To achieve this we explored the nanosecond laser crystallization of a bilayer structure consisting of Au and SiO0.1 layers with thicknesses of 30 nm and 130 nm, respectively. The study reveals that when exposed to 532 nm wavelength radiation leads to its destruction due to rupture. On the other hand, when subjected to 1064 nm wavelength radiation, no similar material behavior is observed, and the measured modification threshold is 0.15 J/cm2, representing a 40 % reduction compared to SiO0.1 film without gold. It is demonstrated that at laser fluences of 0.35 J/cm2 and higher, the treatedsurfaceinair becomes enriched with silicon dioxidenanoporous coating, attributed to the return of evaporation products to the target surface. Theoretical modeling, assuming thermal evaporation of the coating, suggests that the undesirable nanoporous layer formation can be avoided.

Investigation of structural, morphological and optoelectronic properties of (Ni, Co)-doped and (Ni/Co) co-doped SnO2 (110) sprayed thin films

The manuscript details the application of spray pyrolysis for the deposition of an economically viable transparent conductive oxide film comprised of (Ni/Co) co-doped SnO2 on a glass substrate. The primary objective of this research was to systematically examine the impact of Ni/Co co-doping on diverse properties of the SnO2 thin film. These properties encompassed the film's structural composition, surface morphology, optical response, and electrical behaviors. A comparison was made with pure SnO2 film, as well as SnO2 films doped with 3 %Ni and 1 %Co. The results indicate that all the samples exhibited a tetragonal structureThe introduction of Co and Ni atoms had no impact on the favored alignment of the (110) plane or the crystal structure of the SnO2 film. The crystallite size of the pure SnO2 film, as well as the (Co, Ni)-doped and (Ni/Co) co-doped SnO2 films, varied within the range of 11 to 20 nm. Scanning electron microscopy (SEM) images were employed to assess how doping and co-doping influenced the surface characteristics of the films. The presence of pores and/or roughness on the surface resulted in a hydrophilic character and a decrease in the contact angle for the doped films (Ni, Co). However, the co-doped film exhibited a hydrophobic characteristic due to the surface enhancement provided by SnO2:3 %Ni:1 %Co. The research also focused on the optical characteristics of the films, showing a positive impact with the proper incorporation of Ni and Co atoms into the SnO2 lattice. It was notably observed that the addition of Ni and Co atoms improves the optical properties of the undoped transparent SnO2 film in the visible spectrum, with a high transmittance of 87 % achieved for the Ni-doped film. Furthermore, the hydrophobic nature achieved by adding a concentration of 3 %Ni to the SnO2:1 %Co film enhances its optical transmission in the range of 300 nm to 750 nm. The SnO2 film shows an improvement in the electrical resistivity upon doping and co-doping with low resistivity value of 2.22 × 10−2 Ω.cm for the film (3 %Ni/1 %Co)-SnO2. Drawing from these insightful results, the study proposes the potential utilization of (Ni/Co) co-doped SnO2 films as transparent electrodes in optoelectronic applications, especially in the manufacturing of thin film solar cells.

Highly Efficient Cadmium telluride Solar Cell with a Thin CuInTe2 Current Booster: Theoretical Insights

CdTe‐based thin film solar cell has been modeled and enumerated with a thin CuInTe2 (CIT) current booster layer. CdTe‐based n‐CdS/p‐CdTe/p+‐CIT/p++‐WSe2 heterojunction device is evaluated for the highest performance. It is revealed that physical parameters such as thickness, doping, and defects of the CIT layer have a significant influence on the performance of the CdTe solar cell. The device shows an efficiency of 37.46% with an open‐circuit voltage, VOC, of 1.102 V, short‐circuit current density, JSC, of 38.50 mA cm−2, and fill factor, FF, of 88.30%. The use of the photon recycling technique with a Bragg reflector with 98% back and 95% front reflectance only provides an efficiency of ≈44.3% with a current of 45.4 mA cm−2. These findings are very hopeful for the production of efficient CdTe solar cells in the near future.

Crystallization processes for photovoltaic silicon ingots: Status and perspectives

The choice of the crystallization process plays a crucial role in determining the quality and performance of the photovoltaic (PV) silicon ingots, which are subsequently used to manufacture solar cells. Silicon ingots are typically grown using either the Czochralski (Cz) process or the direction solidification (DS) method, with each technique influencing the microstructure and defects density as well as the final solar cells’ performance. In this work, we describe these two processes with a brief overview of the main challenges. For monocrystalline silicon ingots, we discuss the role of crucible and bubble development as well as structure loss. For multicrystalline silicon ingots, we briefly review some of the methods that have been developed in the past years and present results of high-performance multicrystalline (HPMC) ingots.

Dissolvable photovoltaic cells on hydrogel

Solar energy is potentially the largest source of renewable energy for providing electrical power for human society. However, significant advances are required to make photovoltaic technologies have a low-carbon footprint in manufacture, be environmentally friendly at the end of their lives through recyclability, and be biodegradable. Here we report dissolvable organic photovoltaic devices based on poly(2-hydroxyethyl methacrylate), which show equal power conversion efficiency to their glass substrate-based counterparts. We use a novel method of including smectic liquid crystal (7-dioctyl[1]benzothieno[3,2- b][1]benzothiophene, C8-BTBT) as a crystal phase regulator in the heterojunction donor:acceptor polymer system to maintain the disposable organic solar cell efficiency without pre- or post-thermal annealing. The results show strong promise not only for more sustainable solar-cell fabrication but also as disposable and biocompatible solar cells for self-powered (energy harvesting) wearable and biomedical devices.

Review Metode Deposisi Elektrokimia Cu2ZnSnS4 sebagai Lapisan Absorber Sel Surya Lapisan Tipis

Cu2ZnSnS4 is a low-cost and environmentally friendly thin layer solar cell absorber material. The electrochemical deposition method is intended to study because it enables producing films with high homogeneity based on solution precursors. This research review focuses on examining the CZTS electrochemical deposition method in order to identify the effect of the sulfurization process (sulfurization temperature and time) so that the best electrochemical deposition process can be identified for future work of high-efficiency CZTS thin layer solar cell fabrication based on solution precursor. The results show that the Cu2ZnSnS4 layer deposited through the electrochemical method has a 1.4-1.6 eV bandgap range. The etching process to post-annealing 0.1M KCN is crucial to effectively and selectively remove CuS, ZnS, and Cu6Sn5 secondary phases.

Proposal for Promotion of the Solar Photovoltaic Power Industry in Korea

This paper focuses on the crucial role of solar power generation in addressing global warming. It examines South Korea's solar technology, which demonstrates high proficiency at approximately 90% (EU standard) and outperforms the EU in system operation and maintenance. Despite China's lower technological score (87.5%), its competitive pricing has led to an increase in the market share of Chinese products, eroding South Korea's competitiveness. The research identifies cost issues compared to coal and explores avenues for improvement, particularly in direct and indirect cost aspects. In the direct cost domain, proposals include establishing solar cell production facilities in countries with low labor costs and favorable tax incentives to reduce equipment costs. In the indirect cost domain, suggestions involve leveraging building-integrated solar and unused land to cut permit and financial expenses. The paper highlights reasons for the inadequate adoption of building-integrated solar in South Korea, such as mortgage issues, pricing constraints due to the System Marginal Price (SMP) system, and the limited deployment of microgrids. Emphasis is placed on the activation of microgrids, introducing new transaction methods and promoting efficient power transactions through infrastructure. These efforts are expected to lead to the sustained growth of the solar power generation industry in the future.

Controllable Fabrication of Silicon Solar Cells with Inverted or Upright Pyramid Structures by a One-Step Copper Catalysis Method

Silicon has garnered significant attention as the primary material for solar cell preparation. Traditional alkaline etching solutions are limited to creating an upright pyramid structure on monocrystalline silicon surfaces. However, research indicates that an inverted pyramid structure exhibits superior light-trapping properties compared to the upright pyramid structure. In this study, we employed a one-step copper ion metal-assisted chemical etching process to fabricate an inverted pyramid structure on monocrystalline silicon wafers. This method allows for the customization of either inverted or upright pyramid structures by adjusting the concentration of specific solution components. Characterization of the textured silicon wafers reveals that the inverted pyramid structure exhibits lower reflectivity than both the upright pyramid structure and polished silicon. By integrating this texturing technique into the solar cell production line, we successfully produced solar cells with both inverted and upright pyramid structures. Evaluation of various solar cell parameters demonstrates that the inverted pyramid structure outperforms the upright pyramid structure, showcasing lower reflectivity and higher photoelectric conversion efficiency.

Photovoltaic Manufacturing Factories and Industrial Site Environmental Impact Assessment

Life cycle inventories (LCIs) and life cycle assessments (LCAs) of photovoltaic (PV) modules and their components focus on the operations of PV factories, but the factories and industrial site product and construction stages are either not or only partially tackled. This work contributes through the bottom-up, model-based generation of LCIs and LCAs for setting up a vertically integrated 5 GWp/a PV industrial site, including the manufacturing of silicon ingots, wafers, solar cells, and PV modules, on a 50 ha greenfield location. Two comparative LCAs are performed. The first compares the annualized environmental impacts of the developed LCI sets with four existing inventories in the Ecoinvent v3.8 database. The second comparative LCA explores the environmental impact differences concerning the industrial site when using different building systems for the factories. Here, the reference system with a steel structure is compared with two alternative building systems: precast concrete and structural timber. The results show that the wafer, cell, and module factories’ annualized environmental impacts with the Ecoinvent LCIs are strongly overestimated. For the ingot factory, the opposite result is identified. The impacts of all four factories show reductions of between 11.7% and 94.3% for 14 of the 15 impact categories. High mean environmental impact shares of 79.0%, 78.2% and 79.2% for the steel, precast concrete and timber structural building systems, respectively, are generated at the product stage. The process and facilities equipment generates 54.2%, 54.4% and 58.2% of the total product and construction stages’ mean environmental impact shares. The proposed alternative timber building system reduces the environmental impacts in 14 of the 15 evaluated categories, with reductions ranging from 1.1% to 12.4%.

Optimizing the metallization process for high fill factor of n-type crystalline silicon TOPCon solar cells

The primary challenge in solar cell manufacture concerning the metallization process is the need to achieve a balance between the electrical and optical performance of the metal contacts as the contribute to shading and the series resistance (Rs) of solar cells. Addressing these challenges with the optimization of the metallization process is crucial for achieving a high fill factor (FF) in solar cells, as FF is a key parameter indicating the quality and efficiency of a solar cell. An impact of different snap-off, distances between mask and cells, of n-type TOPCon (Tunnel Oxide Passivated Contact) solar cells during the screen-printing process was conducted. This experiment employs testing and analysis to determine the most effective snap-off distance that minimizes the Rs variability, resulting in an overall enhancement in cell efficiency. The smaller snap-off distance can lead to better performance in n-TOPCon solar cells due to finer lines, uniform contacts, and lower Rs. The I-V characteristics of 1.4 mm are Jsc of 39.58 mA/cm2, Voc of 684.63 mV, FF of 80.54 %, and power conversion efficiency (PCE) of 21.83 %, respectively. In addition, dark I-V measurement is essential for diagnosing performance issues; we got shunt resistance (Rsh) of 4.97 x 106 Ω which is the highest value that indicates minimal Rs of 0.3 Ω. As a result, it is a potential strategy for n-TOPCon solar cell improvements.

Fabrication and Properties of Bi2S3 Nanowire Thin Film Solar Cells by Spin Coating with Varying Sulfur Concentrations in the Precursor

We conducted a simple solution-based method to fabricate Bi2S3 nanowire thin film solar cells by spin coating with varying sulfur-to-bismuth ratios. Spherical nanoparticles were observed in the thin film with low-concentration sulfur solution, with these nanoparticles gradually changing to nanorods. Finally, nanowires of Bi2S3 were observed in the thin film with a high sulfur concentration in solution. The band gap gradually decreased with the increase in sulfur concentration. The solar cell performance was significantly improved with the nanowire structure. During film fabrication, sulfur vacancy defects appeared primarily because of high annealing temperatures. These defects were somewhat reduced by the high concentration of sulfur in the solution, supported by the energy-dispersive x-ray spectroscopy (EDS) results. The elemental chemical composition of Bi2S3 material showed an increase in the sulfur-to-bismuth ratio, reaching saturation at almost 0.9. In this work, we systematically observed the effect on the optical properties, surface morphology, and photovoltaic properties by changing the concentration of sulfur in the precursor. The nanowire structure with a high concentration of sulfur in the solution is a promising way to improve the Bi2S3 thin film solar cell.

Investigating the Application and Impact of Laser Etching Technology in the Fabrication of Solar Cells

The most crucial initial step in the metallization process of electroplating is the local contact openings in dielectric layers. In this article, an ultraviolet picosecond laser (UV‐ps), is used to open the front and back dielectric layer of the precursor of n‐TOPCon solar cells. By changing the laser parameters and spot overlap rate, the surface morphology of laser etching under different conditions is obtained and characterized by optical microscope and scanning electron microscope. The results indicate that there are three separate laser shock zones in the dielectric layer under the action of Gaussian light spot, and the corresponding ablation mechanisms are proposed. The longitudinal distribution of B element is characterized by secondary ion mass spectrometry to explore the effect of laser on its pn junction. In addition, the electrical characterization of lifetime photoluminescence is measured and calibrated using WCT120, and this indicates that the majority of the amorphous silicon is recrystallized when applying a fast firing oven process, and this hence improve the minority carrier lifetime and implied open‐circuit voltage. The laser damage to the emitter at the laser‐ablated regions is investigated using the emitter saturation current density, J0laser extracted by WCT120.

Prospects of buffer layer optimization for electrodeposited CZTS-based thin-film solar cell using SCAPS-1D

Kesterite Cu2ZnSnS4 (CZTS) has recently attracted the intensive attention of researchers as a significant photovoltaic material for the scalable production of thin film solar cells. We have particularly focused on replacing the conventional CdS buffer layer with non-toxic and earth-abundant materials of zinc stannate (Zn2SnO[Formula: see text] in environmentally friendly thin-film solar cells based on CZTS. Zinc stannate (ZTO) with a wide bandgap energy of about 3.33[Formula: see text]eV can be a promising material to reduce photon absorption loss and improve the photovoltaic performance of the device. Thus, the absorber and buffer layers were practically prepared to determine the bandgaps of layers for citation in SCAPS-1D simulation program. We employed chemical methods to deposit the CdS and CZTS layers and succeeded to obtain a high-quality kesterite phase of CZTS. The common configuration of FTO/CZTS/buffer/ZnO/AZO was the basis of the simulations in which, the thicknesses of the absorber and buffer layers were optimized by using the SCAPS-1D. According to the outcome of the simulations, the ZTO buffer layer has a better performance than CdS.

Porous PbBr2 films modulation by indium tribromide additive for the fabrication of SnO2-based CsPbBr3 perovskite solar cells

The achievement of complete conversion of PbBr2 films presents a significant challenge in the development of CsPbBr3 films with consistent growth, comprehensive coverage, and controllable components. To address this challenge, introducing a porous structure in the planar PbBr2 film is advantageous for facilitating the immersion of CsBr precursor, thereby reducing impurity phase formation and mitigating strain caused by the film volume expansion. In order to accomplish this, indium tribromide (InBr3) was employed as an additive and the InBr3(DMF)3 adduct was utilized to expedite the release of organic molecules in PbBr2(DMF), resulting in the transformation of planar PbBr2 film into porous structures. The growth orientation of PbBr2 crystals was altered by this transformation, effectively suppressing the generation of metallic Pb impurities in the film. Additionally, it not only optimizes the morphology of CsPbBr3 film but also reduces impurity phase. As a result, the InBr3:CsPbBr3 perovskite solar cell achieved an efficiency of 7.28 %. The majority of In3+ ions were concentrated near the buried interface between SnO2 and InBr3:CsPbBr3, leading to significant improvements in both non-radiative recombination defect states within the perovskite film and electron injection and collection capabilities within the device.

Wet synthesis of Cu2MnSnS4 thin films for photovoltaics: Oxidation control and CdS impact on device performances

The manganese-based quaternary chalcogenide Cu2MnSnS4 could have the chance to promote the production of sustainable solar cells, but the reported photovoltaic efficiencies are still too poor to push the research on the topic. Herein, a low-cost, straightforward, and sustainable wet methodology to synthesise Cu2MnSnS4 thin films is reported. The main issues that hindered their power conversion efficiencies have been investigated. Firstly, the manganese oxidation state has been stabilised by fine-tuning the synthesis parameters. Cu2MnSnS4 was obtained in the crystalline structure of stannite, and no oxygen was found in the material bulk. Prototype devices in substrate configuration were produced, and the new record efficiency (η = 0.92 %) for wet-synthesised Cu2MnSnS4 was reached. Since the photovoltaic performances were poor despite the high quality of Cu2MnSnS4 produced, the interface between the light absorber material and the buffer layer, CdS, was investigated, and its suitability to work as an efficient photovoltaic p-n junction was evaluated. We reveal that the buffer layer deposition procedure highly impacts the composition of the Cu2MnSnS4 surface, and that band alignment between Cu2MnSnS4 and CdS is unfavourable. The statements have been sustained by X-ray diffraction and Raman analysis, X-ray and ultraviolet photoelectron, electron paramagnetic resonance, and energy dispersive X-ray spectroscopies.

Influence of inverted pyramid texturization on front metallization and performance of crystalline silicon solar cells

The silicon surface texturing is an essential part for the fabrication of crystalline silicon solar cells to increase the conversion efficiency. By adjusting the etching texturing condition, inverted pyramid (IP) and upright pyramid (UP) texturization were prepared on crystalline silicon substrates for fabrication of PERC solar cells. The surface morphology not only affects the light trapping but also impacts electrode shading loss and front electrode contact interface. The IP texturization presents better anti-reflective performance due to more common light paths and narrower silver grids owing to less flow of Ag paste on concave blocked structure, both of which results in the higher short-circuit current density (Jsc). Yet in terms of front Ag/Si contact interface, the IP texturization causes more Ag crystallites and more surface recombination under the present condition suitable for UP texturization because of more edges on the upper part of IP, which leads to the lower open-circuit voltage (Voc). The final conversion efficiency of IP solar cells (23.61 %) is 0.06 % higher than that of UP solar cells (23.55 %). An improvement about 0.07 mA/cm2 of Jsc was achieved with IP samples and Voc has a decrease of 0.3 mV caused by the surface recombination on IP texturization. In summary, the structural characteristics of IP results in lower reflectivity and less electrode shading, while Ag/Si contact interface could be optimized by adjusting the processing condition, ultimately promising the higher efficiency.

Enhancing Reproducibility in Organic Solar Cell Fabrication via Static Sequential Deposition with Cross-Linked Polymer Donor and Nonfullerene Acceptor

Enhancing Reproducibility in Organic Solar Cell Fabrication via Static Sequential Deposition with Cross-Linked Polymer Donor and Nonfullerene Acceptor

Effect of Natural Dye Extracts on the Absorbance Characteristics of TiO2 in Dye-Sensitized Solar Cells

Natural dye extracts from Chinese Ixora (Ixora chinensis) flower, Cassod flower (Cassia Siamea), Cassava leaf (Manihot Esculenta), purple heart (Tradescantia Pallida) and Copper leaf (Acalypha Wilkesiana) have been explored as sensitizers for the fabrication of dye-sensitized solar cells. The properties of the dyes were investigated using the FTIR and they all showed broad absorption bands in the 3800 to 3000cm-1 wavelenght and strong presence of intermolecular H-bonds. The effect of dye extracts on the absorbance and transmittance features of TiO2 was well studied by the UV-VIS and the absorbance peak was in the case of sensitization with Manihot Esculenta seen to radically improve above 1.0 at 350nm wavelength. Finally, the current and voltage characteristics of the DSSC were studied in sunlight and at a peak sunlight intensity of 601m/w2, the Manihot and Cassod sensitized devices exhibited maximum voltage values of 115 and 84mV respectively and maximum current values of 4.32 and 2.99mA. These plants have shown great potential for application in fabrication of cost effective and environmentally friendly DSSCs.