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• Passive radiative cooling of c-Si solar cell via transparent multilayer thin film. • 5.6 degree centigrade temperature reduction in solar panel using SR-ARC w.r.t. common single layer Si 3 N 4 ARC. • Increased lifetime of solar module. The crystalline silicon solar module operates in an outdoor environment and exposed to radiation, ambient temperature and humidity. This paper focuses on the performance and lifetime improvement of the generic commercial single-layered Si 3 N 4 coated multi-crystalline silicon solar cell with the addition of selective radiative antireflective coating (SR-ARC). We presented a common approach to radiatively lower the temperature of the solar module through atmospheric and sky emission with keeping or increasing the solar absorption in 300–1150 nm wavelength range. The physical, electrical and optical parameters of the generic solar cell have been tested in the laboratory and implemented in simulation. Further solar cell surface texture parameters have been tested and verified by simulation. At optimised thickness emissivity of the SR-ARC has been calculated in the range of 4–25 µm wavelength. The maximum temperature reduction of 6.8 °C estimated in the double-layer SR-ARC module compared to a single antireflection layer coated multi-crystalline silicon solar module. With the application of triple-layer SR-ARC, absorption has increased, but the emission has been reduced compared to the double layer SR-ARC. After 25 years of field operation, due to the application of SR-ARC, the solar module effective power conversion efficiency is expected to improve by another 1% in absolute term. [ABSTRACT FROM AUTHOR]

Based on the molecular dynamics software package CovalentMD 2.0, the fastest molecular dynamics simulation for covalent crystalline silicon with bond‐order potentials has been implemented on the third highest performance supercomputer "Sunway TaihuLight" in the world (before June 2019), and already obtained 16.0 Pflops (1015 floating point operation per second) in double precision for the simulation of crystalline silicon, which is recordly high for rigorous atomistic simulation of covalent materials. The simulations used up to 160,768 64‐core processors, totally nearly 10.3 million cores, to simulate more than 137 billion silicon atoms, where the parallel efficiency is over 80% on the whole machine. The running performance on a single processor reached 15.1% of its theoretical peak at highest. The longitudinal dimension of the simulated system is far beyond the range with scale‐dependent properties, while the lateral dimension significantly exceeds the experimentally measurable range. Our simulation enables virtual experiments on real‐world nanostructured materials and devices for predicting macroscale properties and behaviors from microscale structures directly, bringing about many exciting new possibilities in nanotechnology, information technology, electronics and renewable energies, etc. © 2019 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Saudi Arabia has developed Saudi Vision 2030, an ambitious plan to reduce the country's dependence on oil by supporting promising private energy organizations and by developing opportunities that contributes to the national economy. In the manufacturing sector, the government is encouraging technology transfers in the renewable energy industries. It is expected to result in the localization of significant parts of the renewable energy value chain in Saudi Arabia. Solar energy systems are proven renewable energy source globally and domestically, it has its long and vast share of experience, from operations and maintenance, to solar data monitoring and gathering. Wide areas had been identified, where this technology can be highly installed and integrated. Components can be manufactured from locally available raw materials to achieve the final products. This study analyzed the key elements of the value chain for producing crystalline silicon solar photovoltaic systems. This paper presents recommendations for localizing this industry in the Kingdom of Saudi Arabia to align with the goals of Saudi Vision 2030. Although these recommendations are based on the environmental conditions of Saudi Arabia, such are also highly relevant for further application to other countries in the Middle East and North Africa region, where widespread energy transitions from fossil fuels to renewable resources are already taking place. [ABSTRACT FROM AUTHOR]

Passivated emitter and rear cell (PERC) concept with an already developed roadmap for 24% efficiency will be leading the photovoltaics industry in the upcoming years. In a few industrial pilot lines, efficiencies above 22% have already been attained. Pilot lines have important roles in bridging lab scale proven concepts with the products which are ready for mass production. Therefore, GUNAM Photovoltaic Line which is specialized on PERC concepts has been established to overcome the barriers that hinder the performance of c-Si solar cells in PERC concepts in a relevant environment. The aim of this article is to show how a loss analysis can be employed in a practical way in an industrially relevant environment. The analysis depends on the first results of the studies from 6 months ramp up period of GPVL. A batch of standard PERC type solar cells with p-type base and atomic layer deposited Al 2 O 3 rear passivation have been fabricated during the ramp up of the line. A detailed gain-loss analysis was performed to address the optical, electrical and recombination losses in order to increase the cell efficiency. • Pilot lines bridge lab scale proven concepts with the products which are ready for mass production. • PERC technology has gained up to 21% market share along all Si based technologies. • Detailed loss analysis helps to draw roadmaps for higher efficiencies. • 19.21% efficiency PERC was fabricated in pilot environment as expected by loss analysis. [ABSTRACT FROM AUTHOR]

The integrated-back contact (IBC) solar cell has attracted wide attention due to its high conversion efficiency, low processing temperature, and thinner substrate from the emerging light trapping of silicon on the pyramidal textured surface. In this paper, a novel IBC solar cell design optimization based on the n-type crystalline silicon wafer was simulated in 2D using Silvaco TCAD tools and the obtained results were compared to the recently published works which allow us to identify the optimum IBC solar cell configuration. In addition, the 2D simulation results are compared to the obtained results by IMEC using SolayTec' ALD (atomic layer deposition) technique. The numerical simulation leads to attaining 24.79% conversion efficiency and 726 mV open-circuit voltage for the considered n-type mono-crystalline silicon solar cell under the AM1.5 spectrum. [ABSTRACT FROM AUTHOR]

[Display omitted] • ALD AZO/sputtered ITO stack shows an excellent passivation effect on Si surface. • The sheet resistance of the AZO/ITO stack is only about 90 Ω/sq. • AZO/ITO stack shows outstanding antireflection effect and no parasitic absorption. • ITO as a cover layer effectively prevents the effusion of H atoms from the AZO. • AZO doping level affects crystalline silicon surface passivation. The surface passivation materials commonly used in crystalline silicon (c-Si) solar cells are either electrically insulating or opaque to the solar spectrum, which poses the electrical loss or optical loss. Hence it is of great significance to explore functional films that are simultaneously transparent, conductive and passivating for c-Si. In this study, we successfully tune two most well-known transparent conductive oxides, i.e. Al-doped ZnO (AZO) and indium tin oxide (ITO), as excellent passivation layers for c-Si surface. The AZO film is grown by atomic layer deposition and is capped with a magnetron-sputtered ITO film. Dynamic secondary ion mass spectrometry reveals that such stack design can retain higher hydrogen concentration on c-Si surface than a single AZO film during annealing. In addition, the AZO should be highly doped to reduce the energy barrier height around c-Si surface, thereby increasing the charge carrier asymmetry and thus reducing surface recombination. It is also highly crucial to optimize the annealing temperature and interfacial silicon oxide. As such, the effective minority carrier lifetime reaches 2.0 ms and the implied open-circuit voltage approaches 700 mV. Besides, the AZO/ITO stacked films possess negligible optical absorption, low sheet resistance (∼90 Ω/sq), and outstanding antireflection effect on c-Si surface. [ABSTRACT FROM AUTHOR]

• Evaluated the temporal variation in glass and aluminum content in silicon modules using specification sheets. • Life cycle impact analysis of silicon module manufacturing, taking into account module designs, manufacturing years, and manufacturing locations. • The aluminum intensity in the module frame decreased by 30% from 2010 to 2021, while the solar glass thickness remained relatively constant. • Local electricity mixes significantly impact the carbon footprint of photovoltaic manufacturing. The growing solar photovoltaic (PV) installations have raised concerns about the life cycle carbon impact of PV manufacturing. While silicon PV modules share a similar framed glass-backsheet structure, the material consumption varies depending on module design, manufacturer, and manufacturing year, leading to varying carbon emissions. However, current life cycle assessment (LCA) studies and public inventory databases of silicon PVs lack an assessment of the variability in commercialized solar module designs and their potential impact on module reliability and carbon footprint. The present study aims to address this research gap by providing a temporal analysis of aluminum and glass intensity in crystalline silicon modules produced from 2006 to 2021. The material inventory data is obtained from specification sheets of 167 crystalline silicon modules produced by 31 manufacturers. Subsequently, we use the collected material inventory to estimate the carbon footprint of manufacturing silicon modules in multiple countries over the past decade. The results reveal a 30% reduction in the aluminum intensity used for frames from 2010 to 2021, while the solar glass thickness remains relatively constant. Additionally, the comparison among manufacturer tiers indicates that more reliable modules tend to use more materials for module production. Moreover, the comparative life cycle assessment of modules manufactured in various countries demonstrates a significant impact of local electricity mixes on the carbon footprint of module manufacturing. Modules manufactured in China exhibit the highest carbon emissions, followed by Malaysia (4–9% lower than China), South Korea (15–16% lower than China), the US (17–18% lower than China), Thailand (19–21% lower than China), Turkey (18–21% lower than China), and Vietnam (25–30% lower than China). Overall, the present study highlights the importance of up-to-date data on material inventory and local electricity mixes in evaluating the environmental impacts associated with PV manufacturing. Lastly, we advocate for integrating the variability of module designs and manufacturing locations within low-carbon solar module criteria and guidelines, recognizing the importance of adaptability in achieving sustainable solar manufacturing. [ABSTRACT FROM AUTHOR]

Expeditious urbanization and rapid industrialization have significantly influenced the rise of energy demand globally in the past two decades. Solar energy is considered a vital energy source that addresses this demand in a cost-effective and environmentally friendly manner. Improving solar cell efficiency is considered a prerequisite to reinforcing silicon solar cells’ growth in the energy market. In this study, the influence of various parameters like the thickness of the absorber or wafer, doping concentration, bulk resistivity, lifetime, and doping levels of the emitter and back surface field, along with the surface recombination velocity (front and back) on solar cell efficiency was investigated using PC1D simulation software. Inferences from the results indicated that the bulk resistivity of 1 Ω·cm; bulk lifetime of 2 ms; emitter (n+) doping concentration of 1×1020 cm−3 and shallow back surface field doping concentration of 1×1018 cm−3; surface recombination velocity maintained in the range of 102 and 103 cm/s obtained a solar cell efficiency of 19%. The Simulation study presented in this article allows faster, simpler, and easier impact analysis of the design considerations on the Si solar cell wafer fabrications with increased performance.

Near infrared hyperspectral photoluminescence imaging of crystalline silicon wafers can reveal new knowledge on the spatial distribution and the spectral response of radiative recombination active defects in the material. The hyperspectral camera applied for this imaging technique is subject to background shot noise as well as to oscillating background noise caused by temperature fluctuations in the camera chip. Standard background noise subtraction methods do not compensate for this oscillation. Many of the defects in silicon wafers lead to photoluminescence emissions with intensities that are one order of magnitude lower than the oscillation in the background noise level. These weak signals are therefore not detected. In this work, we demonstrate an enhanced background noise subtraction scheme that accounts for temporal oscillations as well as spatial differences in the background noise. The enhanced scheme drastically increases the sensitivity of the camera and hence allows for detection of weaker signals. Thus, it may be useful to implement the method in all hyperspectral imaging applications studying weak signals.

Coherent deep ultraviolet (DUV) light sources are crucial for various applications such as nanolithography, biomedical imaging, and spectroscopy. DUV light sources can be generated by using conventional nonlinear optical crystals (NLOs). However, NLOs are limited by their bulky size, inadequate transparency at the DUV regime, and stringent phase-matching requirements for harmonic generation. Recently, dielectric metasurfaces support high Q -factor resonances and offer a promising approach for efficient harmonic generation at short wavelengths. In this study, we demonstrated a crystalline silicon (c-Si) metasurface simultaneously exciting modal phase-matched bound states in the continuum (BIC) resonance at the fundamental wavelength of 840 nm with a higher degree of freedom for precise control of the BIC resonance and a plasmonic resonance at the wavelength of 280 nm in the DUV to enhance third harmonic generation (THG). We experimentally achieved a Q -factor of ∼180 owing to the relatively large refractive index of the c-Si and the geometric symmetry breaking of the structure. We realized THG at a wavelength of 280 nm with a power of 14.5 nW by using a peak power density of 15 GW/cm 2 excitation. The measured THG power is 14 times higher than the state-of-the-art THG dielectric metasurfaces using the same peak power density in the DUV regime, and the maximum obtained THG power enhancement factor is up to 48. This approach relies on the significant third-order nonlinear susceptibility of c-Si, the interband plasmonic nature of the c-Si in the DUV, and the strong field confinement of BIC resonance to boost overall nonlinear conversion efficiency to 5.2 × 10 -6 % in the DUV regime. Our work shows the potential of c-Si BIC metasurfaces for developing efficient and ultracompact DUV light sources using high-efficacy nonlinear optical devices.

We report the effects of H2S passivation on the effective minority carrier lifetime of crystalline silicon (c-Si) wafers. c-Si wafers were thermally annealed under an H2S atmosphere at various temperatures. The initial minority carrier lifetime (6.97 μs) of a c-Si wafer without any passivation treatments was also measured for comparison. The highest minority carrier lifetime gain of 2030% was observed at an annealing temperature of 600 °C. The X-ray photoelectron spectroscopy analysis revealed that S atoms were bonded to Si atoms after H2S annealing treatment. This indicates that the increase in minority carrier lifetime originating from the effect of sulfur passivation on the silicon wafer surface involves dangling bonds.

The Atacama Desert receives the highest levels of solar irradiance in the world with an annual average of 2500 kWh/m2 for the global horizontal irradiance and 3500 kWh/m2 for the direct normal irradiance. One of the challenges is the large portion of ultraviolet light. This part of the spectrum be detrimental for the encapsulant materials, reducing their lifetime. To develop a module adapted to the Atacama Desert conditions, it is imperative to have standardized information from first-hand about the typical faults experienced by photovoltaic modules operating in the desert. This work reports on the design and implementation of the Inspection Data Collection Tool to evaluate crystalline silicon-based moules operating in desert climates. The tool brings together novel features of compatibility with current standards, efficient mobile-type instrumentation (equipment and tools), clear procedures/protocols for non-expert users and low development costs. A total of 95 modules were inspected to characterize failure/degradation issues. Three components of the solar modules were assessed: front cover glass, ethylene-vinyl acetate encapsulant and solar cells. Seven abnormalities were analyzed: Soiling, front cover glass discoloration, encapsulant delamination, hotspots, partial shading, cell fracture and faulty soldering. Soiling was the most common issue, showing correlation between dust deposition and location.

Dispersion models are necessary for precise determination of the dielectric response of materials used in optical and microelectronics industry. Although the study of the dielectric response is often limited only to the dependence of the optical constants on frequency, it is also important to consider its dependence on other quantities characterizing the state of the system. One of the most important quantities determining the state of the condensed matter in equilibrium is temperature. Introducing temperature dependence into dispersion models is quite challenging. A physically correct model of dielectric response must respect three fundamental and one supplementary conditions imposed on the dielectric function. The three fundamental conditions are the time-reversal symmetry, Kramers-Kronig consistency and sum rule. These three fundamental conditions are valid for any material in any state. For systems in equilibrium there is also a supplementary dissipative condition. In this contribution it will be shown how these conditions can be applied in the construction of temperature dependent dispersion models. Practical results will be demonstrated on the temperature dependent dispersion model of crystalline silicon. [ABSTRACT FROM AUTHOR]

Thin crystalline silicon (c‐Si) solar cells are highly attractive for realizing light‐weight and flexible wafer‐based solar cells as well as for reducing the material cost. Silicon heterojunction (SHJ) architecture using hydrogenated amorphous silicon (a‐Si:H) is suitable for realizing very thin c‐Si cells, because of its capability of excellent surface passivation. In this work, the potential of very thin c‐Si solar cells is examined by characterizing SHJ solar cells with a wide range of thicknesses from 50 to 400 μm. A trade‐off between the open‐circuit voltage (VOC) and the short circuit current density (JSC) against wafer thickness is clearly observed in these SHJ cells, whereas a decrease in fill factor (FF) is found for thin SHJ cells below 80 μm. The loss analysis for the thin SHJ cells with numerical simulation clarifies that the infrared parasitic absorption loss due to the supporting layers is enhanced for thinner wafers, which limits the JSC in the thin SHJ cells. In addition, it is confirmed that the FF is more sensitive to surface recombination than the VOC, and this tendency becomes more pronounced with the decrease in the wafer thickness. A high efficiency of 22% is achieved in a SHJ solar cell with a thickness of only 46 μm, demonstrating a high potential for flexible high‐efficiency c‐Si solar cells. [ABSTRACT FROM AUTHOR]

The TISO‐10‐kW plant, installed in Lugano (Switzerland) in 1982, is the first grid‐connected PV plant in Europe. In a joint publication (part 1), we presented the results of the electrical characterization performed in 2017—after 35 years of operation—of the 288 Arco Solar modules constituting the plant. Power degradation rates were different among modules and two groups could clearly be distinguished: group 1, with a remarkably low mean degradation rate of −0.2% per year, and group 2, with a mean degradation of −0.69% per year. After 35 in a temperate climate, approximately 70% of the modules (considering a ±3% measurement uncertainty) still exhibit a performance higher than 80% of their initial value. In this paper, when possible, we attempt at correlating module performance losses to specific failure mechanisms. For this sake, an extensive characterization of the modules was performed using visual inspection, IV curve measurements, electroluminescence, and infrared imaging. We remarkably find that module degradation rates are highly correlated to the aging pattern of the encapsulants used in module manufacturing. In particular, a specific formulation of the encapsulant (PVB), which was used only in a minority of the modules (approximately 10%), leads to degradation rates of −0.2% per year, which corresponds to a loss in performance below 10% over 35 years. Potential safety threats are also investigated, by measuring the frame continuity, the functionality of the bypass diodes, and the module insulation. Finally, we discuss how the analysis of a 35‐year‐old PV module technology could benefit the industry in order to target PV module lifetimes of 40+ years. [ABSTRACT FROM AUTHOR]

• The most critical factors for thermally stable AlO x layer are discovered. • The most significant factor for high quality surface passivation is discovered. • Stoichiometry of the PECVD aluminum oxide layer is firstly reported. • Depth profile and the behaviour of a hydrogen in AlO x is firstly reported. • STEM reveals the c-Si/AlO x interface which affects surface passivation. Plasma-enhanced chemical-vapor deposition systems are commonly used to deposit aluminum oxide (AlO x) on silicon wafers in the production of silicon solar cells. This study investigates the impact of the deposition conditions on the obtained surface passivation quality of p -type wafers. It is the first to investigate the impact of all the five main process parameters. The ratio between the microwave power and the total gas flow rate is identified as a critical condition to form thermally stable layers. We find that the most significant parameter for high quality surface passivation is the flow rate ratio of nitrous oxide (N 2 O) to tri-methyl-aluminum (TMA). Higher flow rate ratio ([N 2 O]/[TMA]) is required to achieve better passivation for fired wafers, whereas lower ratio is preferred when the firing process is not permissible. Elastic-recoil detection analysis reveals that the gas flow rate ratio has a significant impact on the likely direction of hydrogen released from the layer during firing (either to the interface with the silicon wafer or to the environment). Surprisingly, the atomic concentration of aluminum and oxygen is found to be almost stoichiometric regardless of the wide range of the gas flow rate ratios studied in this paper. [ABSTRACT FROM AUTHOR]

Abstract Surface engineering of crystalline silicon (c-Si) is the core of Si-based semiconductor devices. The current commercially available c-Si solar cells achieve this by making use of a conventional thin dielectric film passivation system (TDFPS), including SiO 2 , Al 2 O 3 , SiN x :H and hydrogenated amorphous silicon (a-Si:H) in industry. However, the TDFPS requires high-vacuum and/or high-temperature conditions, which hinders efforts to further reduce the costs of device fabrication. A revolutionized approach to circumvent these issues involves the replacement of TDFPS with new material system which can also achieve high-quality passivation on c-Si surface. Here, we successfully establish and implement a functional group passivation system (FGPS) using a series of functional materials with a sulfonic functional group -SO 3 H, such as 'poly(2-acrylamido-2-methylpropanesulfonic acid)' (PAMPS) and 'polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene, sulfonated, cross-linkable' (PS-b-PERB), which can achieve a highly effective passivation on Si surface, resulting in power conversion efficiencies up to 20% when they are applied in the front surface engineering of interdigitated back contact (IBC) solar cells. Furthermore, the FGPS materials inherently allow passivation layer fabrication in low-temperature and high-vacuum-free conditions. This work provides novel low-cost material strategies without compromise of performance for c-Si surface engineering in the future Si-based photovoltaics. Graphical abstract Image 1 Highlights • It is found that the sulfonic acid group, –SO3H, in a material is responsible for the high-quality passivation effects of this type of material, leading to the discovery of a series of passivation schemes. • A new materials system, i.e., functional group passivation system, is established to engineer Si surface for the suppression of surface/interface recombination. • A multi-functional anti-reflection/surface passivation material, PS-b-PERB film, is developed and applied in the front surface engineering of IBC solar cells, with high power conversion efficiency of 20%. [ABSTRACT FROM AUTHOR]

Studying the kinetics of phase transformation and phase boundary propagation during initial lithiation of silicon electrodes in lithium ion batteries is relevant to understanding their performance. Such studies are usually challenging due to the difficulties in measuring the phase boundary velocity in the interior of the sample. Here we introduce a non-invasive, in situ method to measure the progression of the phase boundary in a planar specimen geometry while maintaining well-controlled lithium flux and potential. We developed an apparatus integrating an electrochemical cell with picosecond ultrasonics to probe the propagating phase boundary in real time. Phase propagation during initial lithiation of crystalline silicon, which is an example of a high capacity anode, is investigated. The primary objective of this manuscript is to report on the experimental technique development and some preliminary results. For lithiation normal to the (100) plane, we observe the phase boundary velocity to be approximately 12 pm/s and x to be 3.73 in LixSi under galvanostatic lithiation with a current density of 40 μA/cm2. The growth rate of the lithiated phase and the reaction rate coefficient are examined using a Deal-Grove type model. [ABSTRACT FROM AUTHOR]

This research paper demonstrates the use of doping concentration effect of front surface field (FSF), back surface field (BSF), and emitter for high-efficiency of n-type monocrystalline silicon (c-Si) interdigitated back-contact (IBC) solar cells using Silvaco TCAD package. The integrated-back contact solar cell is considering as a promising structure due to its high conversion efficiency, thinner substrate, and low-temperature processing of the substrate configuration. From previous research works, the considered IBC cell of 150-μm thick n-type CZ silicon wafers with a half-pitch size of 500 μm is studied and improved for either product quality and lower operating costs. The optimum conversion efficiency of about 24.79% has been achieved with open-circuit voltage up to 726 mV under the AM1.5 spectrum. Furthermore, the solar incident angle plays a critical factor affecting the considered device characteristics and performance of the fixed PV modules. [ABSTRACT FROM AUTHOR]

• Passive radiative cooling of c-Si solar cell via transparent thin film. • Cooling through atmospheric window (8–13 µm wavelength). • The hemispherical and angular emissivity of thin film. • SiO 2 , TiO 2 , Si 3 N 4 , Al 2 O 3 and HfO 2 compared for 3-D emissive properties. In outdoor condition, the performance of the commercial solar photovoltaic (PV) modules depends on various parameters like (1) amount of direct solar radiation, (2) ambient temperature, (3) the location of installation, (4) wind speed, (6) aerosol, and most of these parameters are uncontrollable. The first two of these parameters increase the solar cell operating temperature which in turn decreases the performance of the solar cell. This simulation-based study presents the development of a passive radiative cooling system for a simple flat crystalline silicon (c-Si) solar cell using a thin film of SiO 2 , Al 2 O 3 , Si 3 N 4 , HfO 2 or TiO 2. Some of these materials are being used as an antireflection coating (ARC) in the commercial solar panel for having a suitable refractive index (n) and very low extinction coefficient (k) values in 300–1200 nm wavelength range. In the 8–13 µm wavelength range, the variation of emissivity of the materials w.r.t. thickness and angle have been calculated. The thickness of ARC, the absorptivity of Silicon, the emissivity of ARC in the atmospheric window was also estimated. Suitable ARC cum emissive layer helps the solar cell in absorptivity improvement as well as keeping its temperature near the ambient temperature. The present study finds that Si 3 N 4 is having a higher emissive power than the other materials and increases (10–161.63 W m−2) with the increase in thickness from 20 to 1000 nm in 8–13 µm wavelength range. Material like SiO 2 and Al 2 O 3 have emissivity lower than Si 3 N 4 of comparable thickness. [ABSTRACT FROM AUTHOR]

The TISO‐10‐kW solar plant, connected to the grid in 1982, is the oldest installation of this kind in Europe. Its history is well documented, and the full set of modules has been tested indoors at regular intervals over the years. After 35 years of operation, we observe an increase in the degradation rates and that the distributions of modules' performances are drastically changing compared with previous years. Two groups of modules can be observed: (a) group 1: 21.5% of the modules show a very modest degradation, described by a Gaussian distribution with mean yearly power degradation of only −0.2%/y. (b) Group 2: 72.9% of the modules form a negatively skewed distribution with a long tail described by mode (−0.54%/y), median (−0.62%/y), and mean (−0.69%/y) values. In earlier years, decreases in performances could strongly be correlated to losses in fill factor (FF). After 35 years, the situation changes and, for a subset of modules, losses in the current (Isc) are superimposed to losses in FF. The reasons for this will become clearer in part 2, where we will present results of a detailed visual inspection on the whole set of modules and will focus on safety aspect too. We conclude that, after 35 years of operation in a temperate climate, approximately 60% (~70% if considering a ± 3% measurement uncertainty) of the modules would still satisfy a warranty criteria that module manufacturers are presently considering to apply to the technology of tomorrow: 35 years of operation with a performance threshold set at 80% of the initial value. The TISO‐10‐kW solar plant, connected to the grid in 1982, is the oldest installation of this kind in Europe. After 35 years of operation in a temperate climate, approximately 60% (~70% if considering a ± 3% measurement uncertainty) of the modules would still satisfy a warranty criteria that module manufacturers are presently considering to apply to the technology of tomorrow: 35 years of operation with a performance threshold set at 80% of the initial value. [ABSTRACT FROM AUTHOR]

Abstract We observe an improvement in the passivation quality of silicon nitride (SiN x) films formed on crystalline silicon wafers by catalytic chemical vapor deposition (Cat-CVD) under the storage at room temperature. Fluorescent light illumination enhances the improvement in the passivation quality of Cat-CVD SiN x films, although the passivation quality is also improved in the dark. We do not see any change of bonding configurations in the SiN x films by the storage at room temperature. Capacitance–voltage measurement reveals that an increase in positive charge density in the SiN x films improves their passivation quality. The improvement in the passivation quality of SiN x films is observed for SiN x films deposited at various substrate temperatures, and SiN x films deposited at higher temperature tends to show more significant improvement in the passivation quality. Highlights • Improvement in the quality of SiN x /c-Si interfaces following storage at room temperature. • Additional improvement obtained using fluorescent light illumination. • No change in the bonding configuration seen in the SiNx. • The improvement is caused by an increase in positive charge density in SiN x. [ABSTRACT FROM AUTHOR]

The authors have given results of investigations into the structural and optical properties of InAs nanoclusters formed by the ion-implantation method in silicon and silica matrices. The influence of the heat treatment at a temperature of 900°C and of the irradiation with Xe ions with an energy of 167 MeV and a fluence of 3·1014 cm–2 on the structure and photoluminescence of the formed systems has been found. In the case of the system ″InAs in SiO2″ the irradiation with Xe ions leads to an enhancement of the intensity and a broadening of the luminescence spectrum in the visible spectral region (550–750 nm). The ordering of the nanoclusters and their stretching along the path of the Xe ions in the SiO2 matrix has been found. [ABSTRACT FROM AUTHOR]

The capacitively coupled radio frequency double-pipe plasma discharge jet is used for the etching process. An argon carrier gas is fed through the atmospheric-pressure plasma source; octafluorocyclobutane (C4F8) etch gas is injected into the plasma. Etchings were carried out on a crystalline silicon substrate. The etching characteristics are discussed and the etch rate tendency shows the reliance of C4F8 gas flow rate and oxygen addition. The optimum etching rate of $7.2~\mu \text{m}$ /min was obtained at a plasma power level of 100 W and C4F8 gas flow rate was 250 sccm. From surface profile detection, it displays the etch profile under this atmospheric-pressure plasma jet treatment. This plasma technique could offer a breakthrough for chamber-free dry etching processing. [ABSTRACT FROM AUTHOR]

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