Silicon Modules Research Articles

Safeguard Measures on Imports of Solar Cells and Modules

Within the context of the escape clause concept in international trade law, this articleanalyses the trade safeguard measures that the United States of America has enacted onimports of crystalline silicon photovoltaic (CSPV) cells and modules. An examination of thereasoning behind the United States’ decision to adopt these controls by Section 201 of theTrade Act of 1974 is presented in this article. The study highlights the detrimental effects ofincreased imports and trade on the domestic solar industry. The purpose of this study is todetermine whether or not these measures are by the conditions that are described in theescape clauses of the General Agreement on Tariffs and Trade (GATT) and the Agreementon Safeguards.

Comparative analysis of outdoor energy harvest of organic and silicon solar modules for applications in BIPV systems

Organic photovoltaics (OPV) have the potential to fill niches that traditional silicon photovoltaics (Si-PV) have left open so far. Building-integrated photovoltaics (BIPV) is one key area where OPV modules can play a vital role due to their functional attributes of semitransparency, flexibility, and lightweight. However, the architectural constraints and physical layout of buildings often do not allow the installation of photovoltaic (PV) modules at their optimal angles. Herein, we report the outdoor energy harvest of commercial OPV, and monocrystalline silicon (m-Si) modules mounted at inclinations of 45° and 90°, using the ISOS-O2 protocol as a test standard. The semitransparent OPV modules incorporating a P3HT:PCBM bulk heterojunction absorbing layer were found to offer daily specific energy yields (YF) that are 10–15% higher than those of the m-Si modules at 45° inclination. For vertical (90°) mounting, the YF of the OPV modules is even 24–30% higher than that of their inorganic counterparts, thus making them ideally suited for façade integrated BIPV. Laboratory investigations reveal that the superior performance of OPV modules in the vertical position is mainly due to a strongly enhanced fill factor (FF) at reduced in-plane irradiance. At a 45° inclination, the positive temperature coefficient of the OPV modules also plays an important role during high-irradiance hours.

Segmented Silicon Modulator With a Bandwidth Beyond 67 GHz for High-Speed Signaling

We demonstrate an all-silicon segmented modulator with traveling-wave electrodes, achieving an electro-optic bandwidth beyond 67 GHz and a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$V_\pi$</tex-math></inline-formula> of 5V. We show that dividing a long optical modulator into shorter segments can help achieve a higher bandwidth without compromising modulation efficiency or optical loss. We analyze the bandwidth limitation due to the delay mismatch between the driving and optical signals. We show that the impact of misalignment of driving delays between segments on the overall bandwidth of the modulator can be described by a finite impulse response filter. Using this modulator, we achieve optical transmission of 120 Gbaud 8-level amplitude shift keying with coherent detection. Taking into account the forward error correction overhead, this yields 336.4 Gb/s net on a single polarization. Our design has the potential for achieving 1 Tb/s using dual-polarization IQ modulation.

Omni-junction silicon modulators of unequal proportions for high-speed datacom

Doping profiles are always a key factor in the design of silicon modulators. As the doping in the waveguide cross-section is limited by the compact footprint, three-dimensional complex optimization presents itself as a viable option for improved performance. This work proposes two different types of unequal-proportioned omni-junction modulators obtained by the linear-decline weight particle swarm optimization algorithm with appropriate figure of merits (FOM). With FOM targeting at overall performance, the obtained modulator composed of unequal-proportioned vertical and lateral junctions has high bandwidth of 40 GHz with the VπL of 1.07 V cm. With FOM for higher modulation efficiency, the modulator composed of unequal-proportioned U-shaped and L-shaped junctions demonstrates low VπL of 0.72 V cm and bandwidth maintaining over 36 GHz. The algorithm together with the 3D design method provides greater flexibility in improving the device performance.

X-Intersected Silicon Modulator of Well-Rounded Performance.

In silicon modulator design, implantation is always a key factor, significantly influencing the doping profile and carrier distribution. As waveguide doping is limited by the compact footprint of the modulator rib, three-dimensional complex optimization is a viable option to improve performance. This work proposes an X-intersected modulator based on two inversely slanted junctions using the effective 3D Monte Carlo method for junction generation. The optimized results show that the modulation efficiency of the design is 1.09 V·cm, while the loss is 18 dB/cm, and the 3 dB bandwidth reaches over 35 GHz owing to the decreased resistance and capacitance of the 3D junction. This work demonstrates the benefits of 3D doping design in silicon modulators, contributing to higher efficiency and avoiding additional PN overlap to introduce lower capacitance. The design of 3D doping profiles well balances the DC and AC performance, and provides novel modulator solutions for high-speed datacom.

Short Wavelength Photons Destroying Si–H Bonds and Its Influence on High‐Efficiency Silicon Solar Cells and Modules

Photons of varying wavelengths exert substantial effects on silicon heterojunction (SHJ) solar cells. Collaborative research previously establishes that light soaking with long‐wavelength photons can activate boron doping in hydrogenated amorphous silicon (a‐Si:H), thereby augmenting cell efficiency (Eff). Herein, this investigation is extended, exploring the effects of short‐wavelength photons on a‐Si:H layers, SHJ solar cells, and modules. The ultraviolet A (UVA) light with the wavelengths peak of 365 nm can disrupt Si–H bonds, resulting in a notable reduction in hydrogen content within both intrinsic and doped a‐Si:H films, and the deterioration of deteriorated interface passivation. Following exposure to 60 kWh m−2 of UVA light, both Eff and module power output decrease significantly, primarily attributable to the degradation of open‐circuit voltage and fill factor. As a feasible solution, the application of a light‐soaking process or the implementation of UV band cutoff module encapsulants can effectively mitigate the loss induced by UV irradiation, thereby ensuring the long‐term operation of SHJ solar cells and modules. Herein, a deeper understanding of UV‐induced performance changes in a‐Si:H film and its degradation mechanism for SHJ solar cells are contributed to in this research and also a viable strategy is provided to counter UV‐induced degradation.

Degradation analysis of polycrystalline silicon modules from different manufacturers under the same climatic conditions

Different kinds of photovoltaic modules from various manufacturers have entered the PV market. However, the long-term performance of these modules under outdoor conditions is uncertain. This study evaluated the degradation of polycrystalline silicon modules from 11 different manufacturers installed under the same climatic conditions in Kumasi, Ghana with the aim of predicting the long-term performance of the modules. Specifically, this study sought to: (i) analyse the power degradation rates of the modules and determine the correlation between the degradation and the age of the modules, (ii) determine the correlation between the power degradation and other electrical performance parameters of the modules, (iii) identify the modules with visual defects and compare their degradation rates with the modules without any visual defects, (iv) compare the degradations of PV modules from the same manufacturer installed under the same climatic conditions for the same number of years and (v) assess the installation and maintenance practices that could negatively affect the degradation of the modules. Forty-eight PV modules from 11 different manufacturers were sampled from 12 PV systems installed between 5 and 9 years. The methods used were visual inspection, observation, interviews, and current–voltage (I-V) tracings. The results revealed the mean power degradation rates of the modules between 0.79 and 1.67%/year, contingent on the manufacturer. The power degradation rate had no correlation with the age of the modules but the power degradation of all modules was mainly due to the degradation of short circuit current (Isc) of the modules. Light encapsulant discoloration, dark encapsulant discoloration, minor frames corrosion, and minor metallization discoloration were found on modules from four different manufacturers. However, the degradation of electrical performance parameters could not be solely attributed to these visual defects. Slight variations in degradations were observed for PV modules from the same manufacturer installed under the same climatic conditions for the same number of years. The installation and maintenance practices of the system owners were similar and unlikely to impact differently on the degradation of the modules from different manufacturers.

A comparative study of different polymer materials for the development of flexible crystalline silicon modules

A comparative study of different polymer materials for the development of flexible crystalline silicon modules

Ultrahigh-linearity dual-drive scheme using a single silicon modulator.

Here, a high-linearity dual-drive scheme using a single silicon dual-drive Mach-Zehnder modulator is presented. The bias voltages and RF amplitudes of the two driving arms are adjusted such that the nonlinearity of the transfer function of the Mach-Zehnder interferometer cancels out the nonlinear response of the arms. Using the proposed scheme, the spurious-free dynamic range of the third-order intermodulation distortion is 123.4 dB Hz6/7, which is believed to be a record-breaking value for silicon modulators. In comparison, the result obtained using a conventional single-drive scheme is 102.6 dB·Hz2/3. The proposed scheme could simplify the design of modulators and promote high-performance microwave photonic links.

Graphene Photonics I/Q Modulator for Advanced Modulation Formats.

Starting from its classical domain of long distance links, optical communication is conquering new application areas down to chip-to-chip interconnections in response to the ever-increasing demand for higher bandwidth. The use of coherent modulation formats, typically employed in long-haul systems, is now debated to be extended to short links to increase the bandwidth density. Next-generation transceivers are targeting high bandwidth, high energy efficiency, compact footprint, and low cost. Integrated photonics is the only technology to reach this goal, and silicon photonics is expected to play the leading actor. However, silicon modulators have some limits, in terms of bandwidth and footprint. Graphene is an ideal material to be integrated with silicon photonics to meet the requirements of next generation transceivers. This material provides optimal properties: high mobility, fast carrier dynamics and ultrabroadband optical properties. Graphene photonics for direct detection systems based on binary modulation formats have been demonstrated so far, including electro-absorption modulators, phase modulators, and photodetectors. However, coherent modulation for increased data-rates has not yet been reported for graphene photonics yet. In this work, we present the first graphene photonics I/Q modulator based on four graphene on silicon electro-absorption modulators for advanced modulation formats and demonstrate quadrature phase shift keying (QPSK) modulation up to 40 Gb/s.

Optimization of a Molybdenum Oxide Bilayer Facilitating Hole Transfer in the p/i Interface for Transparent Thin-Film Silicon Solar Cells and Modules Using Laser Scribing

Optimization of a Molybdenum Oxide Bilayer Facilitating Hole Transfer in the p/i Interface for Transparent Thin-Film Silicon Solar Cells and Modules Using Laser Scribing

Large Optical Modulation of Dielectric Huygens’ Metasurface Absorber

AbstractHigh‐index nanostructures are found to exhibit large nonlinearity of spectral responses under photoexcitation, which is applicable to all‐optical modulation. The nonlinearity stems from Mie‐type resonance shift due to photoinduced variation of refractive index. Here, amorphous silicon‐based Huygens’ metasurface absorber and ultrafast excitation are used to demonstrate two orders of magnitude enhancement of modulation depth, both theoretically and experimentally, when electric dipole lattice resonance matches the magnetic dipole resonance. Within a few square micrometer spatial confinement and picosecond scale delay, over 100% photothermal modulation depth is experimentally achieved at matched resonance condition. This concept is not limited to photothermal modulation in the amorphous silicon but is applicable to dielectric materials with various mechanisms to achieve modulation of refractive index. This work opens the avenue toward all‐optical information processing via optimized modulation by careful spatiotemporal and spectral control over a metasurface.

A Spot-Area Method to Evaluate the Incidence Angle Modifier of Photovoltaic Devices—Part 1: Cells

The angle of incidence of solar irradiation on photovoltaic modules varies throughout the day. At larger angles of incidence, the modules are subject to higher reflection losses, resulting in lower light transmission and energy yield. The impact of the relative angular transmittance on the energy yield is often evaluated with a correction factor, commonly referred to as incidence angle modifier (IAM). In this article, a new method to quantify the IAM of photovoltaic devices is presented, which is different from the methods proposed in IEC 61853-2: It encompasses a spot-area irradiation, a customized angle probe holder, and a current-to-voltage converter. This first part focuses on single-cell minimodules and validates the new method on two different cell architectures—an interdigitated back-contact solar cell and a four-busbar solar cell, with an analysis of the measurement bias due to busbars. A second part will follow on the implementation of the same method to commercial-size silicon modules. The study is intended to contribute to the IEC 61853-2 standard. A detailed uncertainty analysis is presented and the method is validated versus IEC 61853-2. Our proposed method shows great potential as it is less expensive and more adaptable than existing standard methods.

System development of silicon photonics links for CERN experiments and accelerators

Future upgrades of the CERN Experiments and Accelerators require optical links capable of handling the large data volume generated in particle detectors and beam position (BPMs) sensors. Silicon Photonics optical transceivers are a promising candidate to process the required data rate as well as efficiently operate in the harsh radiation environment. We present the experimental characterisation of silicon modulators together with demonstration of optical transmitters based on custom designed Silicon Photonics integrated circuits.

Conceptual Design of a Semi-Automatic Process Line for Recycling Photovoltaic Panels as a Way to Ecological Sustainable Production

The article presents the developed technology for the comprehensive recycling of depleted, used or damaged photovoltaic (PV) cells made of crystalline silicon. The developed concepts of technology and the results of research on recycling were presented on silicon photovoltaic cells and modules. The sequence of steps and the type of procedures used are proposed. A thermal delamination method for used commercial photovoltaic modules has been developed to separate the materials. In addition, a recycling line was proposed along with the selection of machines and a holistic approach to project profitability based on a SWOT analysis. The presented semi-automatic installation enables recycling on a laboratory scale. The line was designed for the assumed capacity of 30 t/h. The total energy demand for the designed line was calculated, which showed that 16.49 kWh is needed to recycle 1 ton of photovoltaic laminates. Implementation of developed solutions on an industrial scale will allow to reduce production costs, mainly thanks to energy savings, which translates into less devastation of the natural environment and reduced material consumption. In addition, the implementation of the PV module recycling system will reduce and, consequently, eliminate a significant amount of used PV devices deposited in landfills. The content of the article gives a fresh and innovative look at the essence of photovoltaic panel recycling processes in terms of production benefits as well as financial and environmental benefits.

Efficient and Fast All-Optical Modulator with In Situ Grown MoTe2 Nanosheets on Silicon

All-optical modulators play a key role in building all-optical networks for efficient optical signal processing and have attracted intensive attention. In this paper, all-optical modulators with in situ grown molybdenum telluride (MoTe2) nanosheets on silicon are proposed and demonstrated for the first time with a self-developed complementary-metal-oxide-semiconductor (CMOS)-compatible fabrication processes. For the silicon-based all-optical modulators with a MoTe2-integrated microring resonator and microdisk resonator, the modulation is as efficient as 17.76 and 158.48 pm/mW while the rise/fall time is 3.7/3.6 and 1.5/3.3 μs, respectively. This is the highest tuning efficiency and the fastest response speed among all-optical silicon modulators based on the photothermal effect of two-dimensional materials under the out-of-plane pumping configuration. Furthermore, the manufacturing processes of the present devices are developed from in situ grown MoTe2 nanosheets on a silicon-on-insulator platform, which is CMOS-compatible, stable, and suitable for large-scale photonic integration.

High energy radiation damage on silicon photonic devices: a review

The past decade has witnessed the fast development of silicon photonics. Their superior performance compared with the electronic counterpart has made the silicon photonic device an excellent candidate for data communication, sensing, and computation. Most recently, there has been growing interest in implementing these devices in radiation harsh environments, such as nuclear reactors and outer space, where significant doses of high energy irradiation are present. Therefore, it is of paramount importance to fill in the “knowledge gap” of radiation induced damage in silicon photonic devices and provide mitigation solutions to fulfill the device endurance requirement. In this review, we introduce the damage mechanism and provide a survey on radiation induced effects on silicon photonic devices, including lasers, modulators, detectors, and passive waveguides. Finally, the mitigation strategies are discussed.

Architecture of symmetrical bifacial perovskite/Si/perovskite PV modules and LCOE comparison in bifacial applications

Perovskite on silicon tandem technologies offer a promising way to overcome the efficiency limit of single-junction crystalline silicon modules and are therefore widely studied. Besides the cost reduction potential of using tandem modules in utility-scale PV plants, the application of bifacial PV modules offers additional opportunities to reduce costs by increasing the energy yield. However, the bifaciality factor of tandem PV modules using bifacial crystalline silicon solar cells is typically lower than that of single-junction bifacial modules, considering the asymmetric architecture of the module with higher front-side than rear-side efficiency. In this study, we assess a symmetrical bifacial triple-junction perovskite/silicon/perovskite PV module architecture which allows for a significant improvement of the PV module rear side efficiency. Cost of ownership, energy yield and levelized cost of energy modeling show the superior performance of such modules compared to crystalline silicon and perovskite/silicon tandem modules specifically in vertical mounting applications that are used e.g.in AgriPV or noise protection PV walls on highways.

Electrical performances of pre-production staves for the ATLAS ITk Strip Detector Upgrade

The ATLAS experiment is currently preparing for an upgrade of the inner tracking detector for the High-Luminosity LHC. The new tracker, ITk, employs an all-silicon detector with outer strip layers. The building block of the ITk strip barrel is the stave which consists of a low-mass support structure hosting the common electrical, optical and cooling services as well as 28 silicon modules. In this contribution, we outline the challenging aspects of the stave pre-production testing phase at Brookhaven National Laboratory. The electrical characterization of these staves, hosting the final design of all ASICs, will be discussed in detail.

Choosing The Right Photovoltaic Panel for Electric Vehicles: An Integrated Decision Support Model

In the current era, global carbon emissions are on the rise and to achieve environmental sustainability, greenhouse gas emissions must be reduced to net zero levels with greater reliance on renewable energy sources. Due to the increasing demand for sustainable transportation options, the integration of photovoltaic (PV) panels in electric vehicles (EVs) is considered a promising solution to boost energy efficiency and reduce greenhouse gas emissions. However, selecting the most suitable photovoltaic panel for EVs is a complex process that involves multiple criteria and considerations. This research article presents an integrated decision support model using the Best-Worst Method (BWM) and the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) to assist in selecting the optimal module. The BWM is employed to compute the weights of eight identified criteria, reflecting the preferences and priorities of decision experts. Subsequently, the TOPSIS method is utilized to evaluate and rank a set of PV panel options based on their performance against the identified criteria. The results reveal that a mono-crystalline bulk silicon module is the best alternative followed by multi-silicon modules. This study proposes a structured decision approach for EV manufacturers to select the right PV panel, promoting energy-efficient transportation solutions.