Silicon Modules Research Articles

(Not) in my city: An explorative study on social acceptance of photovoltaic installations on buildings

Existing buildings provide high surface potential for photovoltaic (PV) installations. When deciding whether a building is suitable for solar energy harvesting, social acceptance needs to be considered. While PV is accepted in general, research regarding the acceptance of PV for specific types of buildings is sparse. In two explorative studies, we investigated the building-specific acceptance of PV installations, taking new PV module designs into account.The aim of the first study (N = 76, passersby in the Botanical Garden, Freiburg i. Br. Germany who volunteered to participate) was to investigate which PV module designs are accepted for different buildings. Six different PV crystalline silicon module prototypes varying in color and surface structure were presented on an exhibition table. Using a paper-pencil-survey, participants rated the modules and combined them with presented buildings. Results show that depending on the building, different modules were favored whereby PV modules were chosen mostly due to color integration.In a second study (N = 109, recruited from the participant pool of the institute of psychology, University of Freiburg, Germany, mostly students, and in social media), participants indicated their acceptance of a PV installation for 24 different buildings in an online survey. Results revealed that social acceptance for PV installations on buildings was generally high and was even higher if the PV module was aesthetically integrated or invisibly. PV modules on historical buildings (including a church) were less accepted than on modern buildings. Yet for invisible PV modules, there were no acceptance differences between buildings. Building variables were found to be more important to predict building-specific acceptance than person-related variables such as environmental concerns, values or political attitude.Taken together, the study gives a first insight into the subject of the social acceptance of urban PV installations. Results underline the importance of aesthetic integration and (in)visibility for PV installation on buildings.

RF crosstalk mitigation via floating shields in parallel silicon traveling-wave modulators

High-density integration of electro-optic (E-O) elements in photonic integrated circuits (PICs) offers compact, low-cost high-capacity transceiver modules. Tighter component spacing increases compactness, but leads to crosstalk that can degrade performance. We investigate and characterize the crosstalk between silicon traveling-wave Mach-Zehnder modulators (TW-MZMs) laid out in parallel in PICs. We propose the use of floating shield strips to reduce E-O crosstalk between these TW-MZMs. We show via simulation and experiment that these strips can increase shoreline bandwidth density by nearly 50%. The improvement in E-O crosstalk covers frequencies as high as 60 GHz.

High-speed, low-voltage, low-bit-energy silicon photonic crystal slow-light modulator with impedance-engineered distributed electrodes

Silicon modulators in optical transceivers feature high-density integration and low manufacturing cost, but they also need to deliver high speed and low power consumption to meet the demands of future data centers and high-performance computing. This paper demonstrates a significantly improved 64 Gbps silicon Mach–Zehnder modulator incorporating photonic crystal slow-light phase shifters. By employing distributed electrodes and engineering their impedance, electro-optic phase matching and electrical impedance matching were obtained simultaneously, and the driving voltage was reduced to 0.87 V, which is compatible with fin-type field effect transistors and eliminates the need for additional electrical amplifiers. The bit energy of as low as 59 fJ/bit is comparable to that of microring modulators, while this modulator does not require temperature control like that used for microring modulators, due to its wide working spectrum of 6 nm. These results indicate the potential for addressing power issues in next-generation data infrastructures.

Performance prediction of ventilated building-integrated photovoltaic system with lightweight flexible crystalline silicon module based on experimental fitting method

The novel ventilated building-integrated photovoltaic system with lightweight flexible crystalline silicon modules (VL-BIPV) has a self-weight of only about 6 kg/m2, which helps to address weight-bearing challenges on low-capacity industrial building rooftops. However, the unique thermal dissipation features of the system pose challenges for the analysis of its photovoltaic performance and thermal processes. Therefore, a comparative experimental testing approach was employed, comparing the VL-BIPV system with a conventional rooftop photovoltaic system. Using the efficiency equations of the conventional photovoltaic system as a reference, the functional equations were fitted based on experimental results. Based on typical meteorological year data in Nanjing, annual power generation and PV cell temperature variations were evaluated, along with power generation and carbon reduction benefits over a 25-year lifetime. The results indicate that the VL-BIPV system achieves an annual power generation of 262.22 kWh/m2, a 6.52% increase compared to the conventional system. Additionally, the highest average and maximum cell temperatures in the VL-BIPV system during the year are 58.39 °C and 64.74 °C, respectively, both lower than the conventional system's peak at 68.34 °C. Over a 25-year lifespan, the VL-BIPV system reduces carbon emissions by 20.17 kgCO2/Wp, exceeding the conventional system's reduction by 1.25 kgCO2/Wp.

Power Cycling Performance of 3.3 kV SiC-MOSFETs and the Impact of the Thermo-Mechanical Stress on Humidity Induced Degradation

Recently, silicon carbide (SiC) power modules of the 3.3 kV voltage class became available and are a promising candidate to replace silicon power modules in traction applications. However, the more than three times higher Young’s Modulus compared to silicon leads to a reduced lifetime under thermo-mechanical stress. This could pose a significant obstacle in their implementation, since traction applications are particularly demanding in their mission profiles with respect to load cycling, but also to environmental conditions. Thus, the thermo-mechanical stress is not just limiting the lifetime itself, but might also promote the humidity induced degradation due to delamination or micro-cracks. In this work, multiple power cycling tests at different temperature swings on 3.3 kV SiC MOSFET chips in a power module were performed, to assess their ruggedness under thermo-mechanical stress. Before or afterwards, these modules were tested under standard HV-H3TRB conditions to verify the interaction between thermo-mechanical and humidity stress on the robustness of the modules.

Towards end-of-life of photovoltaic systems in Malaysia: An assessment of management strategies using a life cycle approach

This paper presents the development of photovoltaic (PV) end-of-life (EoL) policy options in Malaysia with consideration of the respective environmental impacts and economic implication. Five policy options were initially formulated based on different combinations of voluntary and regulatory approaches, PV module EoL pathways, i.e. recycling, landfill and incineration, and types of EoL PV modules. Then, the environmental impacts of each option were evaluated using life cycle assessment based on seven relevant impact categories. Later, the economic implication of each policy option was determined based on revenue gained from recovered materials and cost of recycling. Results showed that recycling yields net environmental benefits in all impact categories for crystalline silicon (c-Si) modules and almost all impact categories for cadmium telluride (CdTe) modules. While both regulatory and voluntary approaches offer reduced environmental impacts, the former is more beneficial than the latter as it provides higher quantity of recycled EoL PV modules, net environmental benefit, net primary energy avoidance and net economic benefit. Also, the inclusion of both c-Si and CdTe in recycling is preferred as it yields higher quantity of recycled PV modules as well as higher net environmental benefit and net primary energy avoidance gained in most impact categories. However, the net economic benefit is lower than recycling c-Si alone because the cost of recycling CdTe modules is higher than the revenue gained from recovered materials. These findings seek to assist in establishing sustainable EoL PV management.

Updated sustainability status of cadmium telluride thin‐film photovoltaic systems and projections

AbstractThis paper provides a comprehensive assessment of the up‐to‐date life‐cycle sustainability status of cadmium‐telluride based photovoltaic (PV) systems. Current production modules (Series 6 and Series 7) are analyzed in terms of their energy performance and environmental footprint and compared with the older series 4 module production and current single‐crystalline Silicon (sc‐Si) module production. For fixed‐tilt systems with Series 6 modules operating under average US irradiation of 1800 kWh/m2/year, the global warming potential (GWP) is reduced from 16 g CO2eq/kWh in Series 4 systems to 10 CO2eq/kWh in Series 6 systems. For operation in US‐SW irradiation of 2300 kWh/m2/year, the GWP is reduced from 11 to 8 CO2eq/kWh and for 1‐axis tracking systems operating in Phoenix, Arizona, with point‐of array irradiation of 3051 kWh/m2/year the GWP is reduced to 6.5 CO2eq/kWh. Similar reductions have happened in all environmental indicators. Energy payback times (EPBT) of currently installed systems range from 0.6 years for fixed‐tilt ground‐mounted installations at average US irradiation at latitude tilt installations to 0.3 years for one‐axis trackers at high US‐SW irradiation, considering average fossil‐fuel dominated electricity grids with fuel to electricity conversion efficiency of 0.3. The resulting energy return on energy investment (EROI) also depends on the conversion efficiency of the electricity grid and on the operation life expectance. For a 30‐year operational life and grid conversion efficiency of 0.3, EROI ranges from 50 (at US average irradiation) to 70 for US‐SW irradiation. The EROI declines with increased grid conversion efficiency; for CdTe PV operating in south California with grid conversion efficiency of 49%, the EROI is about 50 and is projected to fall to 30 when the state's 2030 target of 80% renewable energy penetration materializes. Material alternatives that show a potential of further reductions in degradation rates and materials for enhanced encapsulation that would enable longer operation lives have also been investigated. A degradation rate of 0.3%/year, which has been verified by accelerated testing, is assumed in 30‐year scenarios; this is projected to be reduced to 0.2%/year in the near‐term and potentially to 0.1%/year in the longer term. With such low degradation rates and enhanced edge‐sealing, modules can last 40‐ to 50‐years. Consequently, all impact indicators will be proportionally reduced while EROI will increase. This detailed LCA was conducted according to ISO standards and IEA PVPS Task 12 guidelines. The study revealed that the choices of system models, methods and temporal system boundaries can significantly impact the results and points out to the need to include assumptions regarding these choices in the “transparency in reporting” requirements listed in the IEA PVPS Task 12 Guidelines.

Solution-Processed Pb(Zr,Ti)O3 Thin Films with Strong Remnant Pockels Coefficient.

In contrast to the widely studied electrical properties of Pb(Zr,Ti)O3 thin films, which have led to their applicability in various application areas such as thin film capacitors, microelectronics, and ferroelectric memories, the electro-optic (EO) properties are far less studied, which hinders the applicability of Pb(Zr,Ti)O3 films for EO applications such as heterogeneously integrated phase modulators in silicon (Si) photonics. Therefore, the EO properties of Pb(Zr,Ti)O3 films need to be further investigated to pave the way for the applicability of Pb(Zr,Ti)O3 films in EO applications. As the EO properties of ferroelectric thin films strongly depend on their crystal phase and texture, which in turn are influenced by the method of film fabrication. Therefore, in this work, we investigate the EO properties of a promising solution process using a La2O2CO3 template film. We successively characterize the precursor ink, microstructure and EO properties of the solution-processed Pb(Zr,Ti)O3film. The Pb(Zr,Ti)O3 film exhibits a fiber texture and has a large maximum and remnant Pockels coefficient (reff) of 69 pm V-1 and 66 pm V-1, respectively. The integration into a ring resonator-based modulator shows a VπL of 2.019 V cm. The determination of these promising EO properties could further pave the way for the applicability of Pb(Zr,Ti)O3 thin films in Si photonics.

Investigation of the possibility of using depleted bauxite in alumina production at the Pavlodar aluminum plant

The topic of processing low-grade or low-quality bauxite is highly relevant in modern conditions due to the gradual depletion of high-quality bauxite reserves. Consequently, there is an increasing need to explore alternative sources of raw materials for aluminum production and its derivatives. Processing low-quality bauxite ores can become an effective solution, reducing dependence on limited high-quality resources and ensuring production stability in the long term. Such research has significant potential for developing technologies capable of optimizing aluminum production processes and enhancing its competitiveness in the global market. Bauxites from the Krasnooktyabrsky bauxite ore management with low aluminum oxide content (37 – 40% by mass) and a silicon module up to 2.0 are considered as potential blending materials for sintering bauxite in alumina production due to the depletion of high-quality bauxite reserves. This article presents the results of research on their processing into alumina at the Pavlodar Aluminum Plant. Laboratory and pilot-scale studies were conducted to assess the feasibility of using low-quality bauxite in alumina production and to determine the techno-economic indicators of processing. The research results confirmed the technological feasibility of processing depleted bauxites with a silicon module of 1.95 - 2.0 in the sintering section while maintaining the quality of sinter and extracting useful components. The maximum proportion of blending of depleted bauxites with the main bauxite was determined not to exceed 50%.

Towards High-Performance Pockels Effect-Based Modulators: Review and Projections.

The ever-increasing demand for high-speed data transmission in telecommunications and data centers has driven the development of advanced on-chip integrated electro-optic modulators. Silicon modulators, constrained by the relatively weak carrier dispersion effect, face challenges in meeting the stringent requirements of next-generation photonic integrated circuits. Consequently, there has been a growing interest in Pockels effect-based electro-optic modulators, leveraging ferroelectric materials like LiNbO3, BaTiO3, PZT, and LaTiO3. Attributed to the large first-order electro-optic coefficient, researchers have delved into developing modulators with expansive bandwidth, low power consumption, compact size, and linear response. This paper reviews the working principles, fabrication techniques, integration schemes, and recent highlights in Pockels effect-based modulators.

Threshold bounce — occupancy-dependent modulation of the discriminating threshold in silicon detectors

The front-end electronics of silicon detectors are typically designed to ensure optimal noise performance for the expected input charge. A combination of preamplifiers and shaper circuits result in a nontrivial response of the front-end to injected charge, and the magnitude of the response may be sizeable in readout windows subsequent to that in which the charge was initially injected. The modulation of the discriminator threshold due to the superposition of the front-end response across multiple readout windows is coined “threshold bounce”. In this paper, we report a measurement of threshold bounce using silicon modules built for the Phase-II Upgrade of the ATLAS detector at the Large Hadron Collider. These modules utilize ATLAS Binary Chips for their hit readout. The measurement was performed using a micro-focused 15 keV photon beam at the Diamond Light Source synchrotron. The effect of the choice of photon flux and discriminator threshold on the magnitude of the threshold bounce is studied. A Monte Carlo simulation which accounts for the front-end behaviour of the silicon modules is developed, and its predicted hit efficiency is found to be in good agreement with the measured hit efficiency.

Assembly and testing of 2S module prototypes for the CMS Phase-2 outer tracker upgrade

The HL-LHC necessitates a Phase-2 upgrade for the CMS detector, which includes the complete replacement of the existing tracker. The new Outer Tracker incorporates two types of silicon module, 2S and PS, based on an innovative transverse momentum (pT) discrimination idea. By using these modules, the information from the tracker will be sent to the Level-1 (L1) trigger for the first time. They will identify charged particles with pT > 2 GeV, helping to reduce the data sent to the L1 trigger. This paper offers a comprehensive overview of the 2S module prototyping process, which include the precise assembly and testing procedures to ensure their performance and quality before integration into the Outer Tracker. Additionally, to assess the performance of a 2S module in beam, the data from a DESY test beam is reconstructed and analyzed using the Corryvreckan offline reconstruction framework. The results demonstrate agreement to within 1% with those obtained using the EUTelescope framework.

Highly efficient silicon modulator via a slow-wave Michelson structure.

The weak free carrier dispersion effect significantly hinders the adoption of silicon modulators in low-power applications. While various structures have been demonstrated to reduce the half-wave voltage, it is always challenging to balance the trade-off between modulation efficiency and the bandwidth. Here, we demonstrated a slow-wave Michelson structure with 1-mm-long active length. The modulator was designed at the emerging 2-μm wave band which has a stronger free carrier effect. A record high modulation efficiency of 0.29 V·cm was achieved under a carrier depletion mode. The T-rail traveling wave electrodes were designed to improve the modulation bandwidth to 13.3 GHz. Up to 20 Gb/s intensity modulation was achieved at a wavelength of 1976 nm.

Experimental investigation of photoelectrical performance and thermal characteristics of ventilated building-integrated photovoltaic system utilizing lightweight and flexible crystalline silicon module

The existing large-scale of industrial buildings with lightweight insulated roofing structures presents a challenge for traditional glass crystalline silicon photovoltaic (PV) systems due to insufficient load-bearing capacity. Meanwhile, traditional PV rooftop applications also face challenges due to limited rooftop resources. To address these issues, this study proposes a ventilated building-integrated lightweight photovoltaic (VL-BIPV) system. The VL-BIPV system incorporates lightweight and flexible crystalline silicon modules, which increase rooftop load by about 6 kg/m2. Additionally, the system features a ventilation channel design to enhance thermal management performance. To evaluate the PV performance and thermal characteristics of the proposed system, an experimental setup was implemented to compare the performances of the VL-BIPV system with a building-attached lightweight photovoltaic (L-BAPV) system that utilizes color steel sheet base plates. The results demonstrate the exceptional performance of VL-BIPV system, with a 100.56% higher ratio of the product of short-circuit current and open-circuit voltage compared to L-BAPV. Moreover, the VL-BIPV system achieved a 1.77% increase in PV efficiency and a 2.35% enhancement in daily electricity generation. In hot weather, the adoption of VL-BIPV reduced the extreme temperature of PV cells by 9.23 °C below 85 °C, surpassing the 6.29 °C reduction achieved by L-BAPV system. Furthermore, the ventilation channel exhibited a gradual temperature increase with slower changes in the flow direction, while the base plate temperature decreased by 13.41 °C, which indicates that VL-BIPV can effectively reduce solar heat gain in the building envelope and improve the indoor thermal environment. The research findings provide important guidance for promoting and applying VL-BIPV technology in large-scale industrial buildings with low rooftop load-bearing capacity, thereby promoting the production and utilization of clean electricity in industrial parks.

Enhancing photovoltaic module sustainability: Defect analysis on partially repaired modules from Spanish PV plants

Between 2010 and 2022, there has been a significant increase in photovoltaic (PV) solar energy installations, driven by factors such as cost reductions, technological advances, policy support and innovative financing approaches. However, this rapid growth has created a significant challenge in the form of increased PV waste generation, coinciding with global commitments to achieve carbon neutrality by 2050. The potential for reuse of decommissioned PV modules represents an environmentally sustainable way forward that requires a comprehensive assessment of technical, economic, environmental and regulatory considerations. This study focuses on evaluating the impact of defects in partially repaired PV modules from Spanish installations on their power output and efficiency, with the aim of developing strategies to increase reuse and reduce environmental impact. The research focuses on 23 crystalline silicon modules and uses established techniques to evaluate their operational condition, detect defects and assess potential safety risks. Among the defects observed, moisture-induced degradation (MID) emerges as the most prevalent, followed by cracked cells and disconnected areas in cells across different technologies. Notably, despite the presence of defects, approximately 87 % of these modules have a power loss of less than 20 %.

Detailed modeling and numerical analysis of thermo mechanical stresses in the crystalline silicon and thin film PV modules under varying climatic conditions

The present manuscript provides an in-depth analysis of the modeling and simulation of thermo-mechanical stresses in photovoltaic panels using finite element (FEM) analysis. It covers important aspects such as the choice of the model, including governing equations, boundary conditions, and simplifying assumptions. The study mainly focuses on evaluating the impact of environmental conditions on the thermo-mechanical stresses of first-generation c-Si and second-generation thin-film CdTe and a-Si PV panels in five different climatic zones in Algeria. The proposed transient 3D numerical model is validated against experimental measurements by other researchers and the tabulated values of the nominal operating temperature of the cell (NOCT). The obtained results indicate that the first principle stress for the c-Si cell is lower compared to CdTe and a-Si cells; this can be explained by looking at the thickness, as well as the Young modulus of the solar cell. Consequently, in regions or countries with hot climatic conditions or large temperature gradients, it is recommended to use PV panels based on first-generation c-Si cells with glass-glass as the front and back covers.

Recovery of metallic lead from End-Of-Life silicon solar modules using salt bridge electrowinning

Toxic lead (Pb) in end-of-life silicon solar modules must be recovered to keep it out of the environment. Present literature on Pb recovery from solar waste is sparse and uses chemicals like nitric or hydrochloric acid. Previously, the authors reported Pb recovery from silicon modules by leaching and electrowinning in acetic acid. However, the Pb recovered from acetic solution contained a small amount of metallic Pb with the rest being lead oxides/acetates. These Pb compounds require further processing to obtain metallic Pb for reuse in solar panel solder, leading to additional cost and chemical waste. This paper reports recovery of metallic Pb using an electrochemical system with two half cells connected through a salt bridge. The salt bridge enables optimized recovery rates of Pb as high as 99.99 % for synthetic leachates. The first experiment to recover Pb from real silicon module waste shows 80 % recovery without optimization. The new method offers a low-cost, closed-loop, direct pathway to metallic Pb recovery from end-of-life silicon solar modules for reuse in new modules.

An Assessment of a Photovoltaic System’s Performance Based on the Measurements of Electric Parameters under Changing External Conditions

This article presents an analysis of the performance of a 14.04 kWp grid-connected photovoltaic (PV) installation consisting of monocrystalline silicon, polycrystalline silicon and bifacial glass–glass monocrystalline silicon modules. The photovoltaic system was mounted in Poland, a location characterized by temperate climate conditions. On the basis of the obtained results, the photovoltaic parameters were determined in accordance with the international standard. The annual energy yield of the entire system was 1033 kWh/kWp, and the performance ratio achieved was 83%. The highest average daily final yield was in the range of 4.0–4.5 kWh/kWp for each photovoltaic technology under investigation. In the cold part of the year, the efficiency of the photovoltaic modules was estimated to be 15%, and it was estimated to be 7% during the warm part of the year. Array capture losses accounted for around 0.75 kWh/kWp of energy loss per day, whereas the inverter efficiency was over 95% during the months that are beneficial for energy production.

A Bayesian inference approach to extract circuit model parameters and analyze photovoltaic degradation from power production data

Power production data can be a valuable resource to analyze photovoltaic (PV) performance without the need for field surveys. Recent work has demonstrated the exciting possibility of leveraging this data to extract circuit model parameters and current-voltage properties of a PV system, but further development is needed to bolster these initial findings. Here, instead of using a classical optimization approach, we switch to the Bayesian framework to solve this complex multi-solution problem. This allows us to construct probability distributions over the model parameters, get a comprehensive picture of the solution space, and quantify prediction uncertainty. As a result, we can define confidence intervals for the system’s electrical properties and consistently track their daily evolution. Our results are validated with laboratory measurements for five silicon and thin-film modules, and our scalable approach works with on-site as well as online weather data, which opens new prospects for remote PV monitoring, modeling, and degradation analysis for real-life applications.

Analogical environmental cost assessment of silicon flows used in solar panels by the US and China

Achieving carbon neutrality requires deployment of large-scale renewable energy technologies like solar photovoltaic (PV) panels. Nevertheless, methods to ascertain the overall environmental impacts PVs and further improve their sustainability are under-investigated. In an effort to provide more understanding of this crucial topic, this research focuses on silicon flows—a key element for manufacturing crystalline silicon PVs. Using system dynamics modeling, we conduct a comprehensive environmental cost assessment of the silicon flows used in PVs based on a comparative analysis between the United States and China as the leading global PV manufacturers. Despite the advancement in wafer quality, material usage reductions and overall price decreases achieved in recent decades, our results project a substantial increase in energy and water consumption in China related to Metallurgical Grade Si (MG-Si), Solar Grade Si (SoG-Si) and cell manufacturing by 2030. An approximate 6.5 times increase of energy and water consumption is observed for c-Si cell manufacturing in China between 2010 and 2020. In 2030, increases of 70% in energy consumption and 69% in water use are estimated for Chinese MG-Si and SoG-Si production. The most significant environmental impact is observed in silicon cell and module manufacturing in both countries, particularly concerning GHG, SOx and NOx emissions. This study provides valuable insights into the environmental impacts of these two major solar panel manufacturing countries by examining the silicon life cycle, from production to end-of-life.