Search Results (26)

Metallurgical-grade silicon (MG-Si) is an important source material for many industrial applications, including the manufacture of alloys, solar photovoltaics, and electronics. The process to refine raw materials into MG-Si is energy-intensive, with the predominant method of submerged-arc furnaces requiring energy consumption of approximately 11–13 kWh/kg Si. Recent research has discussed promising methods for reducing the energy required for the silicon production process, including the use of molten-salt electrolysis (MSE), a technique that offers potential savings in energy consumption without requiring carbon inputs for the process. This paper presents a techno-economic study of a potential industrial-scale MSE plant for MG-Si production to evaluate the trade-offs between capital and operating costs of the system. Capital costs are sourced from recent MG-Si plants and an existing cost model developed for MSE processes that includes the size of the plant and the operating temperature among its inputs. The results show that MSE technology has the potential to be an economically cost-competitive option for MG-Si production if the technology successfully scales to industrial production and matures enough to allow for financing costs similar to that of a comparably sized submerged-arc furnace plant. Full article

The growing use of integrated circuits has made it essential to assess and minimize the environmental impacts of these systems. As most integrated circuits are manufactured on electronic-grade silicon (EG Si) wafers, the first step is to obtain reliable, consistent and complete life cycle inventory (LCI) data on their production. This work proposes an update to the LCI of EG Si wafers with recent data available for solar-grade silicon (SoG Si) wafers. In addition, as thickness, shape and purity differ greatly between SoG and EG Si wafers, an adaptation to the manufacturing process’s LCI has been made. Full article

Tandem solar cells offer a promising route to surpass single-junction efficiency limits. The amorphous silicon (a-Si)/lead sulfide quantum dot (PbS QD) configuration is a strong candidate for broadband solar spectrum utilization. Planar devices with this material combination suffer from significant optical losses, making advanced light management essential. To address this, we propose a novel experimentally guided nanostructure design. Our proposed method utilizes nanostructures to increase the optical path length by diffracting light to off-normal directions and employs graded-index material stacks to suppress surface reflectance. This work establishes a clear design pathway and provides valuable insights into alternative light management strategies for the future commercialization of these tandem solar cells. Full article

As global economies accelerate their energy transitions, the photovoltaic sector faces critical challenges linked to material supply, security, and sustainability. Solar-grade silicon, enabling over 90 percent of photovoltaic technologies, has become a strategic commodity underpinning the expansion of renewable energy infrastructures. This short communication examines the evolving role of solar-grade silicon within the global energy transition, moving beyond its traditional classification as a technical material to frame it as a commodity of geopolitical and economic significance. We analyze recent price trends, regional production asymmetries, and trade dependencies, identifying key vulnerabilities in current supply chains. Although alternative photovoltaic materials such as perovskites and organics attract research interest, their commercial immaturity reinforces the centrality of silicon. The novelty of this contribution lies in treating solar-grade silicon through a commodity lens, integrating techno-economic metrics with policy and investment considerations. We highlight opportunities for reinforcing supply resilience through domestic production, circular economy strategies such as silicon recovery and reuse, and diversification of technological pathways. Our findings advocate for the inclusion of solar-grade silicon in strategic resource planning and industrial policy frameworks. Recognizing its unique position at the intersection of energy, technology, and trade is essential to achieving secure, scalable, and sustainable photovoltaic deployment worldwide. Full article

As a critical impurity in the production of solar-grade silicon, the concentration of phosphorus (P) significantly affects photoelectric conversion efficiency. To address the challenge of P removal in solar-grade silicon production, this study proposes a combined process of Si-Fe solvent refining and SiO₂-TiO₂-CaO-CaF₂ slag treatment. Under conditions utilizing collaborative refining with an alloy composition of Si-10 wt. %Fe and a slag composition of 32 wt. %SiO₂-48 wt. %CaO-10 wt. %TiO₂-10 wt. %CaF₂, the removal rate of P in silicon can reach up to 96.8%. This paper investigates the effectiveness of combining solvent refining with slag making under fixed conditions of a Si-10 wt. %Fe alloy paired with various slag systems (no slag addition, binary slag SiO₂-TiO₂, ternary slag SiO₂-CaO-TiO₂, and quaternary slag SiO₂-TiO₂-CaO-CaF₂). Based on the experimental results, the optimal TiO₂ content in the slag system for maximizing P removal was analyzed and determined. Finally, leveraging both theoretical analysis and experimental findings, the mechanism of P removal was elucidated as a dual process: P is oxidized into Ca₃(PO₄)₂ within the slag phase, and residual P is captured by the Fe-Si-Ti ternary phase. Full article

The growing demand for renewable energy positions it as a cornerstone for climate change mitigation and greenhouse gas emissions reduction. Although renewable energy sources generate around 30% of global electricity, their production and deployment involve significant environmental challenges. This review analyzes renewable energy projects from a life cycle perspective, focusing on environmental impacts throughout the supply chain. Particular emphasis is placed on the energy-intensive nature of manufacturing phases, which account for 60% to 80% of total emissions. The extraction of critical raw materials such as neodymium, dysprosium, indium, tellurium, and silicon is associated with emission levels ranging from 0.02 to 0.09 kg of carbon dioxide equivalent per kilowatt-hour for rare earth elements, along with an estimated average land degradation of 0.2 hectares per megawatt installed. Furthermore, the production of solar-grade silicon for photovoltaic panels consumes approximately 293 kilowatt-hours of electricity per kilogram, significantly contributing to the overall environmental footprint. Through a comprehensive review of the existing literature, this study integrates life cycle assessment and sustainable supply chain management approaches to identify environmental hotspots, quantify emissions, and propose strategic improvements. The analysis provides a structured, systematized, and data-driven evaluation, highlighting the relevance of circular economy principles, advanced recycling technologies, and digital innovations to enhance sustainability, traceability, and resilience in renewable energy supply chains. This work offers actionable insights for decision-makers and policymakers to guide the low-carbon transition. Full article

The integration of perovskite with silicon for constructing tandem solar cells (TSCs) represents a promising route in photovoltaic technology. The hybrid sequential deposition (HSD) method, combining thermal evaporation and spin-coating, is crucial for developing perovskite films in textured perovskite/silicon tandem solar cells. However, the process faces challenges due to incomplete reactions caused by the dense perovskite coverage layer (CPCL) formed from high-crystallinity precursors. The CPCL hinders the diffusion of organic salts into the bottom precursor layer, leading to performance degradation and accelerated device aging. Herein, this study explores several polar solvents as additives to n-butanol (nBA) solvent in order to enhance the permeability of organic salts through the CPCL, and we demonstrate that dimethyl sulfoxide (DMSO) as an additive solvent can effectively assist organic salts in rapidly diffusing through the precursor layer, thereby promoting the complete transformation of uniform perovskite crystals. The resulting perovskite films exhibited complete conversion, uniform crystallization, and improved quality. As a result, the target TSCs achieved an increased maximum power conversion efficiency (PCE) of 29.12%. This study offers a robust pathway for depositing high-quality perovskite films on industrial-grade textured silicon substrates, laying a solid foundation for advancing perovskite/silicon tandem solar cells technology. Full article

Diamond wire saw silicon slurry (DWSSS) is a waste resource produced during the process of solar-grade silicon wafer preparation with diamond wire sawing. The DWSSS contains 6N grade high-purity silicon and offers a promising resource for high-purity silicon recycling. The current process for silicon extraction recovery from DWSSS presents the disadvantages of lower recovery and secondary pollution. This study focuses on the original DWSSS as the target and proposes flotation for efficiently extracting silicon. The experimental results indicate that the maximal recovery of silicon reached 98.2% under the condition of a dodecylamine (DDA) dosage of 0.6 g·L⁻¹ and natural pH conditions within 24 min, and the flotation conforms to the first-order rate model. Moreover, the mechanism of the interface behavior between DWSSS and DDA revealed that DDA is adsorbed on the surface of silicon though adsorption, and the floatability of silicon is improved. The DFT calculation indicates that DDA can be spontaneously adsorbed with the silicon. The present study demonstrates that flotation is an efficient method for extracting silicon from DWSSS and provides an available option for silicon recovery. Full article

Copper nitride (${\mathrm{Cu}}_3\mathrm{N}$), a metastable poly-crystalline semiconductor material with reasonably high stability at room temperature, is receiving much attention as a very promising next-generation, earth-abundant, thin film solar light absorber. Its non-toxicity, on the other hand, makes it a very attractive eco-friendly (greener from an environmental standpoint) semiconducting material. In the present investigation, ${\mathrm{Cu}}_3\mathrm{N}$ thin films were successfully grown by employing reactive radio-frequency magnetron sputtering at room temperature with an RF-power of 50 W, total working gas pressure of $0.5\mathrm{Pa}$, and partial nitrogen pressures of $0.8$ and $1.0$, respectively, onto glass substrates. We investigated how argon affected the optical properties of the thin films of Cu${}_3$N, with the aim of achieving a low-cost solar light absorber material with the essential characteristics that are needed to replace the more common silicon that is currently in present solar cells. Variable angle spectroscopic ellipsometry measurements were taken at three different angles, ${50}^{\circ }$, ${60}^{\circ }$, and ${70}^{\circ }$, to determine the two ellipsometric parameters psi, $\psi$, and delta, $\Delta$. The bulk planar ${\mathrm{Cu}}_3\mathrm{N}$ layer was characterized by a one-dimensional graded index model together with the combination of a Tauc–Lorentz oscillator, while a Bruggeman effective medium approximation model with a $50\%$ air void was adopted in order to account for the existing surface roughness layer. In addition, the optical properties, such as the energy band gap, refractive index, extinction coefficient, and absorption coefficient, were all accurately found to highlight the true potential of this particular material as a solar light absorber within a photovoltaic device. The direct and indirect band gap energies were precisely computed, and it was found that they fell within the useful energy ranges of $2.14$–$2.25$ eV and $1.45$–$1.71$ eV, respectively. The atomic structure, morphology, and chemical composition of the Cu${}_3$N thin films were analyzed using X-ray diffraction, atomic force microscopy, and energy-dispersive X-ray spectroscopy, respectively. The Cu${}_3$N thin layer thickness, profile texture, and surface topography of the ${\mathrm{Cu}}_3\mathrm{N}$ material were characterized using scanning electron microscopy. Full article

A nondestructive detection method that combines convolutional neural network (CNN) and photoluminescence (PL) imaging was proposed for the multi-classification and multi-grading of defects during the fabrication process of silicon solar cells. In this paper, the PL was applied to collect the images of the defects of solar cells, and an image pre-processing method was introduced for enhancing the features of the defect images. Simultaneously, the defects were defined by 13 categories and three divided grades of each under the definition rules of defects that were proposed in accordance with distribution and characteristics of each defect category, and expand data were processed by various data augmentation. The model was therefore improved and optimized based on the YOLOv5 as the feature extractor and classifier. The capability of the model on distinguishing categories and grades of solar cell defects was improved via parameter tuning and image pre-processing. Through experimental analysis, the optimal combination of hyperparameters and the actual effect of data sample pre-processing on the training results of the neural network were determined. Conclusively, the reasons for the poor recognition results of the small target defects and complex feature defects by the current model were found and further work was confirmed under the foundation of the differences in recognition results between different categories and grades. Full article

In this paper, we use numerical simulations to investigate ultrathin Cu (In_1−xGa_x) Se₂ solar cells. In the first part, we focus on the cell configuration in which the PV parameters fit and match the fabricated cell characteristics. Our goal is to investigate the impact of different loss mechanisms, such as interface trap density (D_it) and absorber trap density (N_t), in different cell pitch sizes on cell performances. D_it defines the number of carrier traps at CIGS/Al₂O₃ interfaces to recombine with photogenerated carriers. N_t defines the number of carrier traps in the absorber layer. Recombination through traps has been found to be the primary loss process in the investigated cell. Additional numerical simulations reveal appreciable gains in cell performance for various cell pitch sizes, absorber doping densities, Ga content, and graded bandgap under AM1.5 illumination. Research during the recent decade has clarified that the most promising strategy to achieve maximum efficiency consists of the so-called tandem configuration. Therefore, we here propose a u-CIGS/PERT silicon device employing, as a top cell, a u-CIGS cell optimized to take into account the above procedure. The results of these simulations provide insights into the optimization of ultrathin-film CIGS solar cells. Full article

Charge carriers’ generation from zinc includes silicon quantum dots (ZnSiQDs) layer sandwiched in-between porous silicon (PSi) and titania nanoparticles (TiO₂NPs) layer-based solar cell is an efficient way to improve the cell’s performance. In this view, ZnSiQDs layer with various QDs sizes have been inserted, separating the PSi and TiO₂NPs layers to achieve some graded bandgap quantum dot solar cells (GBQDSCs). In this process, ZnSiQDs of mean diameter 1.22 nm is first prepared via the top-down method. Next, ZnSiQDs have been re-grown using the bottom-up approach to get various mean diameters of 2.1, 2.7 and 7.4 nm. TiO₂NPs of mean diameter in the range of 3.2 to 33.94 nm have been achieved via thermal annealing. The influence of different ZnSiQDs sizes on the designed GBGQDSCs performance has been determined. The proposed cell attains a short circuit current of 40 mA/cm² and an efficiency of 4.9%. It has been shown that the cell performance enhances by optimizing the energy levels alignment in the PSi, ZnSiQDs, TiO₂NPs layers. Full article

In this review article, the state of the art of the complete processing chain in the production of solar photo-electric modules from raw materials (quartzites, quartz sand) is detailed. In particular, the silicon and silane production technologies of the Institute of Physics and Technology of Almaty, Kazakhstan, can become part of an expansive technologies chain. Such integration could present a number of benefits in comparison with the analogs, including less environmental pressure and increased safety. The combination of innovative production technologies of highly effective solar cells and modules with competitive production technologies of solar-grade silicon and silane constitutes a basis for the creation of an industrial cluster in the field of silicon solar photo energy with a complete vertically integrated production cycle. Full article

Solar grade silicon (SoG-Si) is the core material of solar cells. The removal of boron (B) has always been a challenge in the preparation of high purity Si. Slag refining has always been considered as one of the effective methods to remove B, but the design of refined slag has been limited by the cognition of the relationship between slag structure and impurity removal, and can only rely on the apparent basicity and oxygen potential adjustment of slag based on a large number of conditional experiments. In order to clarify the B removal mechanism of slag refining from Si, nuclear magnetic resonance (NMR) and Raman vibrational spectroscopy were used to investigate in detail the behavior and state of B and aluminum (Al) in the SiO₂–CaO–Al₂O₃–B₂O₃ slag. The role of the degree of B–Si cross linking on the B activity in slag was highlighted by comparing the partition ratio (L_B) between slag and Si. Q² structural unit of slag is an important site for capturing B. BO₄ (1B, 3Si) species is the main form of connection between B and silicate networks, which determines the activity of B in the slag. The addition of Al₂O₃ into SiO₂–CaO slag can change the relative fraction of Q² and BO₄ (1B, 3Si). Increasing Al₂O₃ content from 0 to about 20 wt% can lead to the overall increase of Q² population, and a tendency to decrease first and then increase of BO₄ (1B, 3Si) fraction under both basicity conditions (0.6 and 1.1). When Al₂O₃ content is less than 10 ± 1 wt%, the decrease of BO₄ (1B, 3Si) population plays a major role in deteriorating the connectivity between B and aluminosilicate network, which leads to a higher activity of B. When the Al₂O₃ content is greater than 10 ± 1 wt%, B is incorporated into the silicate network more easily due to the formation of more Q² and BO₄ (1B, 3Si), which contributes to a rapid decline in activity of B in slag. Full article

The market for photovoltaic modules is expanding rapidly, with more than 500 GW installed capacity. Consequently, there is an urgent need to prepare for the comprehensive recycling of end-of-life solar modules. Crystalline silicon remains the primary photovoltaic technology, with CdTe and CIGS taking up much of the remaining market. Modules can be separated by crushing or cutting, or by thermal or solvent-based delamination. Separation and extraction of semiconductor materials can be achieved through manual, mechanical, wet or dry chemical means, or a combination. Crystalline silicon modules are currently recycled through crushing and mechanical separation, but procedures do exist for extraction and processing of intact wafers or wafer pieces. Use of these processes could lead to the recovery of higher grades of silicon. CdTe panels are mostly recycled using a chemical leaching process, with the metals recovered from the leachate. CIGS can be recycled through oxidative removal of selenium and thermochemical recovery of the metals, or by electrochemical or hydrometallurgical means. A remaining area of concern is recycling of the polymeric encapsulant and backsheet materials. There is a move away from the use of fluorinated backsheet polymers which may allow for improved recycling, but further research is required to identify materials which can be recycled readily whilst also being able to withstand outdoor environments for multi-decadal timespans. Full article