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A perfect blackbody can emit radiation of up to 480 Wm-2 at 60°C into the atmospheric window in the sky. However, designing such ARC (antireflective coating) for solar cells that can work as ARC and radiative coolers is challenging. A crystalline solar module having a single ARC of Si3N4 can emit radiation into the sky at about 84 Wm-2. In Contrast, at 35°C ambient temperature, our suggested ARC using Si3N4/SiO2/PDMS (polydimethylsiloxane) may emit around 346 Wm-2. This significant thermal emission lowers the solar module's temperature from 60.15°C to 48.55°C. This reduction in the solar module's temperature leads to an efficiency improvement of about 0.56%, and more importantly, the module's lifetime will increase by 25 years. [ABSTRACT FROM AUTHOR]

To design a high‐efficiency crystalline silicon (c‐Si) photocathode, the photovoltage and photocurrent generated by the device must be maximized because these factors directly affect the hydrogen evolution reaction (HER). In this study, a c‐Si p–n junction is used to enhance the photovoltage of the c‐Si photocathode, and a tapered microwire array structure is introduced to increase the photocurrent. When tapered microwire arrays are employed on the front surface of the c‐Si photocathode, a current density of ≈41.7 mA cm−2 is achieved at 0 VRHE (reversible hydrogen electrode); this current density is the highest among all reported photocathodes including c‐Si, approaching the theoretical maximum value for c‐Si. Furthermore, a Ni foil/Pt catalyst is introduced on the opposite side of the incident light, simultaneously serving as an electrocatalyst to reduce side reactions in the HER and encapsulation layer to prevent c‐Si from contacting the electrolyte. Thus, a stable device is developed using c‐Si photoelectrochemical cells that have an efficiency exceeding 97% for >1000 h. [ABSTRACT FROM AUTHOR]

Spatial atomic layer deposition (SALD) is applied to the electronic passivation of moderately doped (≈1016 cm−3) p‐type crystalline silicon surfaces by thin layers of hafnium oxide (HfO2). For 10 nm thick HfO2 layers annealed at 400 °C, an effective surface recombination velocity Seff of 4 cm s−1 is achieved, which is below what has been reported before on moderately doped p‐type silicon. The one‐sun implied open‐circuit voltage amounts to iVoc = 727 mV. After firing at 700 °C peak temperature in a conveyor‐belt furnace, as applied in the production of solar cells, still a good level of surface passivation with an Seff of 21 cm s−1 is attained. Reducing the HfO2 thickness to 1 nm, the passivation virtually vanishes after firing (i.e., Seff > 1000 cm s−1). However, by adding a capping layer of plasma‐enhanced‐chemical‐vapor‐deposited hydrogen‐rich silicon nitride (SiNx) onto the 1 nm HfO2, a substantially improved firing stability is attained, as demonstrated by Seff values as low as 30 cm s−1 after firing, which is attributed to the hydrogenation of interface states. The presented study demonstrates that SALD‐deposited HfO2 layers and HfO2/SiNx stacks have the potential to evolve into an attractive surface passivation scheme for future solar cells. [ABSTRACT FROM AUTHOR]

This study utilizes Quokka3, an advanced solar cell simulation program, specifically tailored for interdigitated back‐contact (IBC) crystalline silicon (c‐Si) solar cells. Through meticulous Quokka3 simulations, the influence of several geometric and wafer characteristics of the solar cell backside on current–voltage (I–V) performance has been scientifically explored for IBC c‐Si solar cells. The investigation encompasses parameters such as wafer thickness, bulk lifetime, resistivity, emitter and back surface field area fraction, and front‐ and rear‐surface passivation. Optimal values for these parameters have been proposed to enhance the efficiency of IBC solar cells. These recommendations contain an emitter percentage of 70%, a wafer thickness ranging from 200 μm, a wafer resistivity of 1 Ω cm, and a wafer bulk lifetime of at least 10 ms. Moreover, under conditions where the cell is not short‐circuited, the potential for achieving higher cell efficiency, up to 26.64%, has been shown. [ABSTRACT FROM AUTHOR]

Currently, enterprises producing crystalline silicon are facing the formation and accumulation of large volumes of microsilica, a technogenic dusty waste formed during the melting of silicon alloys. Due to its chemical composition, this waste can be a significant raw material for metallurgical production. Therefore, this study is aimed to solve the problem of recycling microsilica. For these studies, a technology for the combined briquetting of microsilica and a carbonaceous reducing agent was developed for the production of a pilot batch of briquettes. This paper presents the results obtained from the process of testing the melting of crystalline (technical) silicon from briquetted monocharge obtained from microsilica. The tests were conducted under large-scale laboratory conditions on a 200 kVA ore-thermal furnace, where 30, 50, and 100% replacements of the traditional charge mixture with briquettes were tested. The results of this study showed that briquettes in the melting process of technical silicon can be successfully used in the range of 0 to 50%. The use of briquettes can significantly improve the technological indicators. The maximum extraction of silicon (approximately 83%) was achieved at 30% replacement. The technical and economic indicators of the process also improved. In particular, an increase in productivity was observed in comparison with tests on a traditional charge. [ABSTRACT FROM AUTHOR]

Daylight photoluminescence imaging of crystalline silicon photovoltaic modules is demonstrated for modules embedded in rooftop and utility‐scale systems, using inverters to electrically switch the operating point of the array. The method enables rapid and high‐quality luminescence image acquisition during the day, unlocking efficient performance and quality monitoring without the need to connect specific electrical hardware or to make any modifications to the system wiring. The principle of the measurement approach is discussed, and experimental results from a 12‐kWDC residential rooftop system and from a 149 MWDC utility‐scale photovoltaic power plant are presented. Measurements were performed using commercial inverters without modifications to the inverter hardware or firmware. In the case of the utility‐scale power plant, the daylight photoluminescence image acquisition of modules connected to a central inverter was obtained from a remote piloted aircraft. Data analysis includes the conversion of photoluminescence image data into implied voltage differences. [ABSTRACT FROM AUTHOR]

Transparent solar cells (TSCs) hold substantial potential as continuous energy generators, enabling their use in situations where conventional devices may not be feasible. However, research aimed at modularizing TSCs for the purpose of regulating the overall voltage and current they produce, a critical step toward practical application, is still in its nascent stages. In this study, we explored a custom-designed, all-back-contact (ABC) configuration, which situates all electrical contacts on the rear side, to create glass-like transparent crystalline silicon (c-Si) solar cells and seamless modules. The ABC design not only demonstrates high power conversion efficiency (PCE) in solar cells but also ensures unobstructed visibility through transparent solar modules. Notably, ABC-transparent c-Si solar cells achieved a peak PCE of 15.8% while maintaining an average visible transmittance of 20%. Through seamlessly interconnecting the unit cells, the output voltage and power were systematically tuned from 0.64 V and 15.8 mW (for a 1 cm²-sized unit cell) to 10.0 V and 235 mW (for a 16 cm²-sized module). Furthermore, we successfully demonstrated the photocharging of a smartphone using a transparent ABC solar module. [ABSTRACT FROM AUTHOR]

This paper proposes two types of electro-refractive optical modulator structures as a fully CMOS-compatible alternative solution. These modulators leverage the properties of amorphous (top) and crystalline (bottom) silicon films surrounding silicon nitride waveguides operating in the C-band communications range at a wavelength of 1550 nm. Various structures have been demonstrated and explored to compete with or surpass the current state-of-the-art performance of thermal tuners, the most widely used tuning mechanism in silicon nitride integrated photonics. Designs utilizing vertical and lateral p–n junctions with amorphous or crystalline films have been simulated and proposed. For the lateral p–n junctions, modulator lengths to achieve a π phase shift smaller than 287 μm have been demonstrated for the TE mode and that smaller than 1937 μm for the TM mode, reaching 168 μm in the case of a lateral p–n junction that is completely a p-doped region over or under the waveguide for TE, and 1107 μm for TM. Power consumption is higher for the TM modes than for the TE, being in the order of 100 mW for the former and lower than 23 mW for the latter. The modulators exhibit higher losses for amorphous material compared to crystalline, with losses smaller than 10.21 dB and 3.2 dB, respectively. The vertical p–n junctions present a larger footprint than the lateral ones, 5.03 mm for TE and 38.75 mm for TM, with losses lower than 3.16 dB and 3.95 dB, respectively, for the crystalline silicon. Also, their power consumption is on the order of 21 mW for TE and 164 mW for TM. [ABSTRACT FROM AUTHOR]

This study systematically evaluates Phototovoltaic (PV) system energy losses and performance quality across selected locations in sub-Saharan African (SSA). Utilising a computational model for a hypothetical 10 kWp crystalline silicon (c-Si) PV system, the research categorises energy losses into irradiance (kWh/m²) and electricity production (kWh/kWp). Key contributors to irradiance losses include angular reflectivity, dirt, dust, and soiling, while inverter and radiation conversion, spectral correction, transformer and cabling, and mismatch are identified as main sources of PV system energy losses. Tilt and orientation impact the transformation of Global Horizontal Irradiance (GHI) into Global Tilted Irradiance (GTI), with the highest gain in Pretoria (215.4 kWh/m²) and the least in Kinshasa (3.6 kWh/m²). The study notes the highest PV system energy loss in Pretoria (346.2 kWh/kWp) and the least in Kinshasa (267.4 kWh/kWp). Despite variations in energy loss sources, the cumulative degradation rate is reported as 12.8% for all locations over a 25-year lifespan. The annual average performance ratio (PR) and capacity factor (CF) range from 77.4%/19.7% in Pretoria to 77.4%/15.6% in Kinshasa. Ambient conditions, including wind speed, relative humidity, precipitation, and temperature, are identified as key factors influencing solar irradiance and PV system losses. The study suggests preventive measures such as optimal system design, the use of bypass diodes, and high-quality PV panels.

Nowadays, an increasing share of photovoltaic (PV) systems makes use of module‐ or submodule‐level power electronics (PE). Furthermore, PE is used in stand‐alone devices powered by PV‐storage solutions. One way to facilitate further implementation of PE in PV applications is to integrate PE components into crystalline silicon PV cells. Herein, the COSMOS device is introduced, denoting COmbined Solar cell and metal‐oxide‐semiconductor field‐effect transistor (MOSFET). Specifically, the combined manufacturing of lateral power MOSFETs and interdigitated back contact solar cells with tunnel‐oxide passivated contacts (TOPCon) on a single wafer is reported. Many steps of the proposed process flow are used for the fabrication of both devices, enabling cost‐effective integration of the MOSFET. Both n‐type solar cells with integrated p‐channel MOSFETs (PMOS) and p‐type solar cells with integrated n‐channel MOSFETs (NMOS) are successfully manufactured. NMOS devices perform better in achieving low on‐resistance, while PMOS devices exhibit lower leakage currents. Furthermore, the study reveals integration challenges where off‐state leakage currents of the MOSFET can increase due to illumination and specific configurations of monolithic interconnections between the MOSFET and the solar cell. Nevertheless, for both n‐type and p‐type solar cells, efficiencies exceeding 20% are achieved, highlighting the potential of the proposed process for COSMOS devices. [ABSTRACT FROM AUTHOR]

Abstract To design a high‐efficiency crystalline silicon (c‐Si) photocathode, the photovoltage and photocurrent generated by the device must be maximized because these factors directly affect the hydrogen evolution reaction (HER). In this study, a c‐Si p–n junction is used to enhance the photovoltage of the c‐Si photocathode, and a tapered microwire array structure is introduced to increase the photocurrent. When tapered microwire arrays are employed on the front surface of the c‐Si photocathode, a current density of ≈41.7 mA cm−2 is achieved at 0 VRHE (reversible hydrogen electrode); this current density is the highest among all reported photocathodes including c‐Si, approaching the theoretical maximum value for c‐Si. Furthermore, a Ni foil/Pt catalyst is introduced on the opposite side of the incident light, simultaneously serving as an electrocatalyst to reduce side reactions in the HER and encapsulation layer to prevent c‐Si from contacting the electrolyte. Thus, a stable device is developed using c‐Si photoelectrochemical cells that have an efficiency exceeding 97% for >1000 h.

Dislocation is a common extended defect in crystalline silicon solar cells, which affects the recombination characteristics of solar cells by forming deep‐level defect states in the silicon bandgap, thereby reducing the lifetime of minority carrier. Hence, reducing the impact of defects on device performance is an effective strategy to optimize the performance of photovoltaic devices. This article reviews the observation and engineering of dislocation in Si solar cell. The structure and deformation of Si can be directly observed by chemical etching combined with electron microscopy. Also, more information about dislocation is obtained indirectly by monitoring the electrical and optical properties of Si. The classification, density, distribution of dislocations, and their interactions with other defects in Si can affect the lifetime of minority carriers and thereby reduce the performance of Si solar cells. In order to achieve higher cell efficiency, crystals with less or even no dislocation should be obtained. In addition to the specification of controlling the relevant parameters during the growth of silicon ingots to obtain the minimum dislocation density, it is necessary to study the behavior of dislocation in Si wafers under the combined action of external stress, temperature, and other defects. [ABSTRACT FROM AUTHOR]

In this work, ray tracing is used to investigate the optical characteristics of various surface structures in ultrathin crystalline silicon (c-Si) for solar cells. Ultrathin c-Si with a thickness of 20 μm is used as the substrate. The light trapping includes front upright pyramids with a molybdenum oxides (MoOx) anti-reflection (AR) layer. Planar ultrathin c-Si (without a MoOx AR layer and upright pyramids) is used as a reference. The wafer ray tracer was developed by a photovoltaic (PV) lighthouse to model the MoOx AR layer to reduce the front surface reflectance and impacts of the AR layer on ultrathin Si solar cells. The optical properties are calculated on the AM1.5 global solar energy spectrum across the 200–1200 nm wavelength region. From the absorbance profile, the photogenerated current density (Jph) in the substrate is also calculated with various surface structures. The front upright pyramids with the MoOx layer result in the largest absorbance enhancement due to the enhanced light scattering by the pyramids and MoOx AR layer. The Jph of 37.41 mA/cm2 is improved when compared to the planar ultrathin c-Si reference. This study is significant as it illustrates the potential of ultrathin c-Si as a promising PV module technology in the future.

ABSTRACT: Introduction. In the article we analysed the technology for producing silicon from rice husks. The analysis showed that the production of polycrystalline and amorphous silicon based on rice waste in the form of rice husk solves the simultaneous disposal of rice waste. Rice husk processing produces valuable organic products, and the residual solid waste mainly contains silicon, carbon and other trace metal elements. Therefore, obtaining silicon and silicon-containing materials from rice husk is relevant. Methods and materials. Various methods for obtaining silicon from rice husk are given. Among them, the methods of chlorination and sublimation were chosen, and experimental installations were assembled to conduct the experiment. The object of study was samples obtained from rice husks of Uzgen rice in the Kyrgyz Republic. Results. The composition and structure of rice husks for the production of crystalline silicon were studied. Lime milk was used to purify toxic chlorine-containing gases in the air of the working area and atmospheric air. The condensing system, designed to capture volatile chlorides, has two receivers. In the first receiver at a temperature of 60°C, condensation of iron, aluminum and magnesium chlorides occurs. It has been established that highly volatile silicon (IV) chloride (SiCl4) at a given temperature remains in the gaseous phase and is completely distilled off in the next receiver of the refrigerator. This indicates that the silicon is in the form of SiCl4 (60°C) and condenses only at a lower temperature in the next receiver. The data obtained indicate that when the temperature rises to 200°C, the process of chlorination of metal compounds initiates. The optimal conditions for maximum extraction of metals and silicon tetrachloride from rice husk were identified: temperature 500–550°C and time 120 minutes. Non-volatile chlorides of calcium, sodium, potassium and other elements form a floating mixture at 450°C. During the reaction, metal chlorides harden and settle on the cold walls of the reactor. Therefore, at this temperature there is not enough heat to maintain them in a gaseous state, and they condense to form solid precipitates. Lime milk containing CaO – 130 g/dm2 is a very effective and cheap means for purifying toxic chlorine-containing gases in the air of the working area and atmospheric air. At high temperatures (1050–1100°C), it is possible to activate chemical reactions between the carrier gas (hydrogen) and silicon chloride (SiCl4), which promotes the decomposition of SiCl4 into components, including silicon and hydrogen chloride, and also provides certain conditions for the formation and deposition silicon crystals. Conclusion. A technology for producing polycrystalline silicon by chlorination from rice husks of Uzgen rice of the Kyrgyz Republic has been studied and developed.

Dislocation is a common extended defect in crystalline silicon solar cells, which affects the recombination characteristics of solar cells by forming deep‐level defect states in the silicon bandgap, thereby reducing the lifetime of minority carrier. Hence, reducing the impact of defects on device performance is an effective strategy to optimize the performance of photovoltaic devices. This article reviews the observation and engineering of dislocation in Si solar cell. The structure and deformation of Si can be directly observed by chemical etching combined with electron microscopy. Also, more information about dislocation is obtained indirectly by monitoring the electrical and optical properties of Si. The classification, density, distribution of dislocations, and their interactions with other defects in Si can affect the lifetime of minority carriers and thereby reduce the performance of Si solar cells. In order to achieve higher cell efficiency, crystals with less or even no dislocation should be obtained. In addition to the specification of controlling the relevant parameters during the growth of silicon ingots to obtain the minimum dislocation density, it is necessary to study the behavior of dislocation in Si wafers under the combined action of external stress, temperature, and other defects.

To grow a defect-free epitaxial silicon wafer (EpiWafer) on a reorganized porous silicon layer stack, the surface must be closed, smooth and particle-free. A post-porosification cleaning step prior to reorganization should significantly reduce the density of (metallic) particles on the surface. In this paper we systematically investigate the influence of different post-porosification cleaning steps on the porous layer stack. The different cleaning steps have no significant effect on the layer thicknesses. On the other hand, the porosities change after the different cleaning steps. The change in porosity correlates very well with the oxidizing effect of the solution used: SC-1 cleaning has the strongest oxidizing effect, followed by ozone cleaning, piranha cleaning and HCl cleaning. A single HF dip has the smallest effect on porosity, showing the small influence of the native silicon oxide layer formed by aging on porosity. Except for the SC-1 cleaning, the other cleanings show no significant change in the Raman peak shift and therefore in stress compared to the as-etched sample. For the SC-1 cleaning, the increase in Raman peak shift and thus stress correlates well with the increase in porosity. After a reorganization step at 1120°C, it is observed that a higher porosity of the low porosity layer in the stack leads to larger pores.

Most crystalline Si based solar cells, e.g. passivated emitter and rear cells, rely on SiNy:H and AlOx/SiNy:H passivation layers. In this work, the long-term behavior of minority charge carrier lifetime in such symmetrically passivated samples during illuminated annealing at elevated temperatures is investigated by means of photoconductance decay based lifetime measurements, corona charging and capacitance voltage measurements. Thereby, AlOx layers, which are known to reduce H in-diffusion due to their barrier properties, deposited by atmospheric pressure chemical vapor deposition as well as by atomic layer deposition were considered enabling a comparison of different deposition techniques. The frequently published behavior of the bulk related degradation could be confirmed and the qualitative correlation between maximum defect density and the changing total amount of H in the Si bulk due to the barrier properties of the individual layers dielectric layers could be shown. Furthermore, for the subsequently observed degradation accelerated by a treatment at higher temperatures, literature indicates degradation to be caused by surface related degradation. Investigations on field effect passivation during degradation by means of corona charging and CV measurements showed a large drop in fixed negative charges in the passivation layer stacks.

Light and elevated temperature-induced degradation (LeTID) is causing a reduction in efficiency especially in p-type silicon based solar cells. It is assumed to be strongly influenced by the hydrogen content in the bulk material. The presented work focuses on the impact of differently thick (5-25 nm) atomic layer-deposited aluminum oxide (AlOx) interlayers underneath the hydrogen-rich silicon nitride (SiNy:H) capping layer. The interlayer acts as a diffusion barrier for H during the firing step. It is demonstrated that the AlOx interlayer has a comparable effect on the LeTID kinetics in Ga-doped Cz-Si (Cz-Si:Ga) as it is observed in B-doped Cz-Si (Cz-Si:B). Additionally, it substantially minimizes lifetime degradation in the Cz-Si:Ga sample. With a determined ratio of electron to hole capture cross sections k=26(3), the degradation phenomena are attributed to the LeTID kinetics. Deposition of AlOx barrier layers exceeding 10 nm in thickness does not yield additional positive effects. Resistivity measurements revealed that the change in hole concentration correlates with the defect density for varying AlOx layer thicknesses. The doping concentration seems to influence the change in maximum defect density for varying AlOx layer thicknesses.

In this work, ray tracing is used to investigate the optical characteristics of various surface structures in ultrathin crystalline silicon (c-Si) for solar cells. Ultrathin c-Si with a thickness of 20 μm is used as the substrate. The light trapping includes front upright pyramids with a molybdenum oxides (MoOx) anti-reflection (AR) layer. Planar ultrathin c-Si (without a MoOx AR layer and upright pyramids) is used as a reference. The wafer ray tracer was developed by a photovoltaic (PV) lighthouse to model the MoOx AR layer to reduce the front surface reflectance and impacts of the AR layer on ultrathin Si solar cells. The optical properties are calculated on the AM1.5 global solar energy spectrum across the 200–1200 nm wavelength region. From the absorbance profile, the photogenerated current density (Jph) in the substrate is also calculated with various surface structures. The front upright pyramids with the MoOx layer result in the largest absorbance enhancement due to the enhanced light scattering by the pyramids and MoOx AR layer. The Jph of 37.41 mA/cm² is improved when compared to the planar ultrathin c-Si reference. This study is significant as it illustrates the potential of ultrathin c-Si as a promising PV module technology in the future. [ABSTRACT FROM AUTHOR]

Photovoltaic installed cumulative capacity reached 849.5 GW worldwide at the end of 2021, and it is expected to rise to 5 TW by 2030. The sustainability of this massive deployment of photovoltaic modules is analysed in this article. A literature review, completed with our own research for emerging technologies has been carried out following life cycle assessment (LCA) methodology complying with ISO 14040 and ISO 14044 standards. Different impact categories have been analysed for five commercial photovoltaic technologies comprising more than 99% of current market (crystalline silicon ~94% and thin film ~6%) and a representative of an emerging technology (hybrid perovskite). By using data from LCA inventories, a quantitative result for 15 impact categories has been calculated at midpoint and then aggregated in four endpoint categories of damage following ReCiPe pathways (global warming potential, human health damage, ecosystems damage and resources depletion) in order to enable a comparison to other renewable, fossil fuel and nuclear electricity production. In all categories, solar electricity has much lower impacts than fossil fuel electricity. This information is complemented with an analysis of the production of minerals with data from the British Geological Survey; the ratio of world production to photovoltaic demand is calculated for 2019 and projected to 2030, thus quantifying the potential risks arising from silver scarcity for c‐Si technology, from tellurium for CdTe technology and from indium for CIGS and organic or hybrid emerging technologies. Mineral scarcity may pose some risk for CdTe and CIGS technologies, while c‐Si based technology is only affected by silver dependence that can be avoided with other metals replacement for electrodes. When the risks grow higher, investment in recycling should boost the recovery ratio of minerals and other components from PV module waste. [ABSTRACT FROM AUTHOR]

In this paper, we presented a simulation method to assess and evaluate the performance of a simple optical design composed of a split spectrum combined with a solar concentrator, both spectrum splitter and solar concentrator, which are commonly numerically designed and optimized on Trace Pro. A comprehensive explanation based on numerical simulation using ray tracing with realistic irradiation conditions is presented to demonstrate the possibility of employing a spectrum-splitting system to improve solar energy conversion and to explain the essential importance of optical concentration in such a system. The analysis demonstrates an increase in electricity efficiency, and the [Yellow Green] spectral range shows the most effective absorption for silicon solar cells compared to [Red Orange] and [Blue Purple] spectral ranges. The solar cells get an additional performance boost from the concentration incorporated. The following approach is expected to result in a more usable design, it allows for more efficient use of solar energy and potentially achieves much higher conversion efficiencies, a way of reducing production costs and increasing the output of the photovoltaic cell. [ABSTRACT FROM AUTHOR]

A modified design of the a‐Si thin‐film solar cell (TFSC) is presented. The c‐Si cap layer is introduced to increase the photon absorption and hence the enhanced photo carriers increase the overall short‐circuit current. Whereas, the highly doped a‐Si passivation layer reduces the minority carrier flow and recombination at the rear side of the cell, and therefore the passivation layer is used to improve the open‐circuit voltage (Voc). The performance optimization and investigation of the cell characteristic is executed using the numerical simulation methodology. To further enhance the cell efficiency, the thickness and doping concentration of the c‐Si cap and a‐Si passivation layer are optimized. The improvement in absorption and passivation quality of the cell leads to the enhancement of 10.54% in short‐circuit current density and 71.51% improvement in the Voc, respectively. The designed a‐Si TFSC absorbs the incoming solar spectrum from 300 to 850nm of wavelength and rest of the spectrum is transmitted. The external and internal quantum efficiency of the cell is well over 95%. The optimized efficiency of 15.33% is obtained for the designed cap layered a‐Si passivated cell in AM1.5 G environment using ray‐tracing methodology. [ABSTRACT FROM AUTHOR]

A device simulation model for localized contact rear side oxide-passivated solar cell has been developed to study the effects of rear contact coverage and fixed charge density dependent field-effect passivation on the performance of $p$ -Si solar cell. Models describing hetero-interface physics related to metal-semiconductor, metal-oxide-semiconductor junctions and interface recombination are considered in the simulation, results of which are verified with the reported experimental data. A detailed analysis of the effect of surface passivation is presented and an analytical design with optimized set of parameters is outlined for fabricating the cell. The result shows that the efficiency of the solar cell can be substantially enhanced by controlling parameters mainly the ratio between localized back contact to the non-contact area and the fixed charge density at the oxide-interface. A maximum efficiency of $\sim $ 25% for a crystalline $p$ -Si solar cell with a comparatively lower lifetime can be obtained by a suitable choice of the design parameters with an added suitable choice of doping concentration in the emitter and absorber and the oxide layer thickness.

In this study, photovoltaic (PV) systems, which have a key role in reducing the consumption of fossil-based energy resources, are analyzed within the scope of sustainability. PV systems, which have an important share among renewable energy sources, will cause environmental and economic consequences at the end of their economic life. While PV modules contribute to clean energy production for an average lifetime of 25-30 years, they also contain potential dangers for our world. Producers, consumers, governments, and researchers related to PV module wastes, which will be encountered more intensively in the near future, should take responsibility more quickly and initiatives on this issue should be supported by policies. In this study, the PV system installed capacity and the amount of PV module waste that will be generated in Turkey until 2050 are evaluated in ten-year periods. Monthly and annual increases are considered separately for the installed capacity estimates and compared with the data published by the Ministry of Energy and Natural Resources (MENR). Waste potential estimates are considered as end-of-economic life and early waste. The total waste potential is evaluated according to future projections published by the International Energy Agency (IEA) and the International Renewable Energy Agency (IRENA). The results show that the PV installed capacity estimates are close to the ETKB estimates, and the waste potential will be approximately three times the size of the projections prepared by IEA and IRENA for Turkey. Accordingly, PV module waste potential is estimated to reach 1 million 706 thousand 159 tons in 2050. [ABSTRACT FROM AUTHOR]

The crystalline silicon (c - Si ) thin film solar cell with one-dimensional (1D) sinusoidal grating has been simulated to explore the absorption enhancement, by utilizing COMSOL Multiphysics Rf Module ( 5.3 a ). The finite element analysis (FEA) is applied to optimize the geometrical parameter of 1D sinusoidal grating, i.e., slit width (w ) and film thickness (t ), for enhancing the light absorption. The slit width is optimized by implementing near-field analysis and far-field analysis at constant periodicity (700 nm). To study the appropriate value of gold (Au) film thickness for the optimization of the grating device, the transmission spectra ( λ , a ) have been calculated for different Au film thicknesses while shedding light into the device at normal incidence keeping periodicity and slit width constant. The proposed 1D sinusoidal grating offers maximum optical coupling efficiency of 88.5%, with the relative transmission of 0.022 ( a. u ) at 350 nm optimal slit width. It divulges the fact that such a grating device exhibits less scattering of surface plasmon polariton (SPP) from the grating profile as it supports the most efficient mode (fundamental plasmonic mode), leading to more absorption in a thin active layer. [ABSTRACT FROM AUTHOR]

This study entails the examination of tunnel oxide passivated contact on p‐type silicon wafers (p‐TOPCon) passivated with n‐polysilicon for a solar cell by using Quokka‐3, a numerical simulation program. The effects of the thickness, bulk lifetime, resistivity, and selectivity of charge carriers due to the polysilicon passivated contact are investigated. Through such n‐polysilicon passivated contact, the back‐emitter solar cells engender higher internal power owing to enhanced surface passivation. This further reduces the shading loss due to front metallization; however, the reduced minority carrier lifetime of the p‐type Czochralski (Cz) wafer restricts the possibilities for high efficiency. Subsequently, the minority charge carrier lifetime of the p‐type wafer conceivably becomes an obstacle to realizing TOPCon solar cells with a high conversion efficiency. This study demonstrates that a configuration suitable for the industrial manufacturing of high‐efficiency solar cells is a crystalline silicon solar cell on a p‐type wafer through a rear‐emitter n‐polysilicon passivated contact. A roadmap toward 24.87% of the p‐TOPCon solar cells through the n‐type polysilicon passivated contact is also devised. [ABSTRACT FROM AUTHOR]

Solar energy is currently one of the most promising clean energy sources and the use of solar energy has led to a rapid increase in the number of solar cells. As one of the fastest-growing electronic wastes, the resource treatment of solar cells at the end of their life should not be neglected. This review discusses the trend for the market development of crystalline-silicon solar cells and analyzes their physical structure and composition. It also discusses the current domestic and international recycling technologies for crystalline-silicon solar cells, including manual dismantling, inorganic acid dissolution, the combination of heat-treatment and chemical methods, and organic solvent dissolution. The shortcomings of the above treatment methods are discussed and some views on the recycling of waste crystalline-silicon solar cells are presented. Constructive suggestions for the green and sustainable development of crystalline-silicon solar cells are put forward by comparing different treatment-recycling processes. [ABSTRACT FROM AUTHOR]

This study focuses on boron‐doped p+polysilicon (poly‐Si) passivating contacts using spin‐on doping (SOD). Experimental conditions, including annealing conditions, SOD concentration, and poly‐Si thickness, were controlled to improve passivation. Based on the analysis results, the passivation quality mainly changes with indiffusion and doping concentration, causing Auger recombination and field effects. Meanwhile, grain size also influences the passivation quality but showed marginal characteristics. Through further optimization using an etch back and diffusion barrier, the efficiency of the flat reference solar cell was improved to 17.5% with an open‐circuit voltage of 695 mV using a p+ poly‐Si contact emitter, the highest reported efficiency using SOD on saw‐damage‐etched surfaces. This study includes a detailed analysis of SOD p+ poly‐Si and shows promising results with potential for application in tandem devices. Furthermore, the cell efficiency is expected to increase by controlling the doping profile and application of textured surfaces, selective emitters, and forming gas annealing (FGA). Highlights: The passivation quality of p + poly‐Si passivating contacts with boron SOD was investigated.The factors influencing the passivation quality of p+ poly‐Si were crystallinity (grain size), indiffusion of boron into the bulk, and doping concentration (field effect).The doping process was further optimized by controlling the boron indiffusion from the SOD source to c‐Si bulk using an additional diffusion barrier layer that controls the boron doping profile.Poly‐Si contact cells with both‐side flat surfaces and poly‐Si contacts showed a maximum efficiency of 17.5% with VOC of 695 mV when a developed p+ poly‐Si was applied at the front. This is the highest reported efficiency using boron SOD‐doped p+ poly‐Si emitter on saw‐damage‐etched flat surfaces.Based on a wide range of analyses and experimental results, a 3D energy band diagram of p+ poly‐Si/SiO x/c‐Si passivating contacts is exhibited.The cell result validates its potential for use in silicon‐based tandem solar cells and the efficiency can be further improved by applying textured surfaces, FGA, and selective emitter for improved metal contacts. [ABSTRACT FROM AUTHOR]

In this study, a molybdenum oxide (MoO x ) and aluminum (Al) contact structure for crystalline silicon (c-Si) solar cells is investigated using a combination of transmission line measurements (TLM) and in-situ transmission electron microscopy (TEM). Cross-sectional high-resolution TEM (HRTEM) micrographs reveal a ≈2 nm silicon oxide (SiO x ) interlayer at c-Si/MoO x interface in the as-deposited state, indicating that formation of SiO x occurs during deposition of MoO x . Moreover, oxygen diffusion takes place from MoO x toward Al resulting in the formation of a ≈2–3 nm aluminum oxide (AlO x ) interlayer at the MoO x /Al interface. Overall, it is observed that MoO x /Al contact is relatively stable upon annealing up to 200 °C and still retains ohmic transport with sufficiently low contact resistivity.

The reduction of carrier recombination processes by surface passivation is vital for highly efficient crystalline silicon (c-Si) solar cells and bulk wafer metrological characterization. Herein, we report a dip coating passivation of silicon surfaces in ambient air and temperature with Nafion, achieving a champion effective carrier lifetime of 12 ms on high resistivity n-type c-Si, which is comparable to state-of-the-art passivation methods. Nafion is a nonreactive polymer with strong Lewis acidity, thus leading to the formation of a large density of fixed charges at silicon surface, 1-2 orders of magnitude higher than what is achievable with conventional thin-film passivation layers. Notably, Nafion passivates the c-Si surface only by the fixed charges without chemical modification of dangling bonds, which is fundamentally different from the common practice of combining chemical with field-effect passivation. This dip coating process is simple and robust, without the need for complex equipment or parameter optimization as there is no chemical reaction involved.

Solar energy is free from noise and environmental pollution. It could be used to replace non-renewable sources such as fossil fuels, which are in limited supply and have negative environmental impacts. The first generation of solar cells was made from crystalline silicon. They were relatively efficient, however very expensive because they require a lot of energy to purify the silicon. Nowadays, the production of solar cells has been improved since the first generation (thin-film solar cells, dye-sensitized solar cells, perovskite solar cells, and organic solar cells). In this work, the development of solar cells was discussed. The advantages, limitations, challenges, and future trends of these solar cells were also reported. Lastly, this article emphasized the various practices to promote solar energy and highlighted the power conversion efficiency of the fabricated devices. [ABSTRACT FROM AUTHOR]

Recently perovskite/crystalline Si (cSi) tandem cells draw considerable attention because their high efficiency can reduce the levelized cost of electricity and increase the power density of photovoltaics (PVs) to accelerate the energy transition. While the theoretical limits for tandem cells are well known, the practical limits are less clear. Herein, a new method is presented to calculate the efficiency of a four-terminal (4T) tandem based on the performance of singlejunction perovskite and cSi cells, using their detailed-balance efficiency fraction. This calculation method is validated with experiments on 4T perovskite/cSi tandem cells that provide a maximum efficiency of 28.0% and with the literature data available for similar configurations. A maximum efficiency of about 36% is estimated for 4T perovskite/cSi tandem cells that would use present record perovskite and cSi PV cells. This can be regarded as the practical efficiency limit for 4T perovskite/cSi tandem devices. [ABSTRACT FROM AUTHOR]

The impedance of solar cells can be leveraged for a variety of innovative applications. However, for the continued advancement of such applications, it is crucial to understand how the impedance varies during practical operation. This work characterizes the impedance of modern crystalline silicon solar cells across different bias voltages and under varying illumination and temperature conditions. It is found that for a given bias voltage, variations in temperature have a notably stronger impact on PN junction impedance than changes in irradiance. However, during maximum power point (MPP) tracking, variations in irradiance have a larger influence on the PN junction impedance than temperature variations. This is related to the shifting operating voltage during operation. Furthermore, it is shown that the capacitance during practical operation can strongly vary for different solar cells. For instance, the areal MPP capacitance values of the two cells tested in this study at 0.1 sun irradiance and a temperature of 30 °C were 0.283 μ F/cm2 and 20.2 μ F/cm2, a 71-fold difference. Conversely, the range of the MPP diffusion resistance was found to be highly similar for different cells. The results of this study enhance the understanding of solar-cell impedance and have a broad applicability. • The effect of illumination and temperature on solar-cell impedance is analyzed. • Temperature affects the capacitance–voltage relationship more than illumination. • During real-world operation, MPPT continually changes the bias voltage. • Accounting for MPPT, illumination dominates the operational MPP impedance. • Two cells show a 71-fold difference in areal MPP capacitance in the same conditions. [ABSTRACT FROM AUTHOR]

• Simple and accurate method to translate I-V curves of c-Si PV modules. • Correction of the I-V curve of c-Si PV modules to STC from a single measurement. • The novel method applies to I-V curves of PV modules, strings and arrays. • The accuracy is comparable to Procedure 1 of the IEC 60891 standard. In the expanding field of photovoltaic solar energy, it is often necessary to apply a correction method to I-V curves measured outdoors and translate them to standard test conditions (STC). The international standard IEC 60891 serves as a primary reference for correction methods, but its application is not straightforward in the case of outdoor photovoltaic strings. Even for photovoltaic modules, this standard requires measurements of several I-V curves under controlled conditions to determine the parameters, which makes the procedure experimentally complex. An essential correction method should avoid additional measurements and provide an uncertainty comparable to IEC 60891, especially for outdoor measurements. In this paper, a novel method is presented in which the correction of the I-V curve is performed without additional measurements. The method is based on procedure 1 of IEC 60891, in which the parameters for the correction of the I-V curve are determined by iterative processes via the linear correction of the maximum power with temperature and irradiance. The new method was tested for both indoor and outdoor measurements. The method showed an uncertainty of less than ± 2 % in the maximum power of the corrected curves. This method can be implemented in spreadsheets and offers an alternative with similar accuracy to method 1 of IEC 60891, while maintaining the simplicity of the correction by using only the measured curve and the values of the temperature coefficients of the photovoltaic modules. [ABSTRACT FROM AUTHOR]

The angular distribution function of multiple scattering experienced by 855 MeV electrons passing through an amorphous silicon plate and an oriented silicon crystal has been studied by means of relativistic molecular dynamics simulations using two types of the potentials that describe electron–atom interaction. The differences in the angular distributions of the beam particles in both media are analyzed. The results obtained are compared to the experimental data and to the results of Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

Due to the shortage of energy in the world, solar energy has received widespread attention as an inexhaustible new green energy and as one of the main sources of power. Many researchers have studied the various materials and efficiencies of solar cells; however, how to extend the life of solar cells has rarely been studied. At present, the main encapsulating method of solar cells is to seal their surface with films such as ethylene-vinyl acetate and polyvinyl butyral. The main problem that has been encountered is that the erosion of water and oxygen leads to a reduction in the service life and efficiency of solar cells. Inspired by the solar panels of satellites in space, a revolutionary vacuum-glazing encapsulating solution with zero H2O and O2 has been invented. The experimental results have nearly doubled the 30–35-year service life of solar cells, based on deep learning predictions. Therefore, the building integrated photovoltaic can be used for the 70-year life of a building. The method is applicable to various solar cells, such as crystalline Si cells, CIGS, CdTe and perovskite film cells, etc. In practice, the main problems encountered in the encapsulation of vacuum glazing include the following: ensuring that the supporting pillar does not pierce the thin film PV and that it is placed accurately between the band gaps; ensuring that the emission of heat is not conducted in a vacuum; ensuring that the sealing sheet covers cover the exhausting port on the glass accurately; maintaining the vacuum degree for a long time; insulating the edge of the sealing materials, as well as other issues. The above problems have been solved perfectly through machine learning of computer vision and the design structure of the thin film PV. [ABSTRACT FROM AUTHOR]

Tandem structures have been introduced to the photovoltaics (PV) market to boost power conversion efficiency (PCE). Single-junction cells’ PCE, either in a homojunction or heterojunction format, are clipped to a theoretical limit associated with the absorbing material bandgap. Scaling up the single-junction cells to a multi-junction tandem structure penetrates such limits. One of the promising tandem structures is the perovskite over silicon topology. Si junction is utilized as a counter bare cell with perovskites layer above, under applying the bandgap engineering aspects. Herein, we adopt BaTiO3/CsPbCl3/MAPbBr3/CH3NH3PbI3/c-Si tandem structure to be investigated. In tandem PVs, various input parameters can be tuned to maximize PCE, leading to a massive increase in the input combinations. Such a vast dataset directly reflects the computational requirements needed to simulate the wide range of combinations and the computational time. In this study, we seed our random-forest machine learning model with the 3×106 points’ dataset with our optoelectronic numerical model in SCAPS. The machine learning could estimate the maximum PCE limit of the proposed tandem structure at around 37.8%, which is more than double the bare Si-cell reported by 18%. [ABSTRACT FROM AUTHOR]

Degradation from ultraviolet (UV) radiation has become prevalent in the front of solar cells due to the introduction of UV‐transmitting encapsulants in photovoltaic (PV) module construction. Here, we examine UV‐induced degradation (UVID) in various commercial, unencapsulated crystalline silicon cell technologies, including bifacial silicon heterojunction (HJ), interdigitated back contact (IBC), passivated emitter and rear contact (PERC), and passivated emitter rear totally diffused (PERT) solar cells. We performed UV exposure tests using UVA‐340 fluorescent lamps at 1.24 W·m−2 (at 340 nm) and 45°C through 4.02 MJ·m−2 (2000 h). Our results showed that modern cell architectures are more vulnerable to UVID, leading to a significant power decrease (−3.6% on average; −11.8% maximum) compared with the conventional aluminum back surface field (Al‐BSF) cells (<−1% on average). The power degradation is largely caused by the decrease in short‐circuit current and open‐circuit voltage. A greater power decrease is observed in bifacial cells with rear‐side exposure compared with those with front‐side exposure, indicating that the rear side is more susceptible to UV damage. Secondary ion mass spectroscopy (SIMS) confirmed an increase in hydrogen concentration near the Si/passivation interface in HJ and IBC cells after UV exposure; the excess of hydrogen could result in hydrogen‐induced degradation and subsequently cause higher recombination losses. Additionally, surface oxidation and hot‐carrier damage were identified in PERT cells. Using a spectral‐based analysis, we obtained an acceleration factor of 5× between unpackaged cells (containing a silicon nitride antireflective coating on the front) in the UV test and an encapsulated module (with the front glass and encapsulant blocking 90% of the UV at 294 nm and 353 nm, respectively) in outdoor conditions. From the analytical calculations, we show that a UV‐blocking encapsulant can reduce UV transmission in the module by an additional factor of ~50. [ABSTRACT FROM AUTHOR]

Existing production technologies for special types of coke are analyzed, with a view to electrofurnace production of metallic silicon. The selection of the initial material is considered; long-flame Shubarkol coal is chosen. Conditions for thermooxidative coking of special coke are outlined. Experimental data are presented for the physicomechanical and metallurgical properties of such coke. [ABSTRACT FROM AUTHOR]

In crystalline silicon, atomic hydrogen released from hydrogen dimers forms acceptor–hydrogen pairs during annealing in the dark at elevated temperatures. In this study, the formation of boron–hydrogen (BH) and gallium–hydrogen (GaH) pairs in 1 Ω cm silicon is investigated at temperatures ranging from 140 to 220 °C. Acceptor–hydrogen concentrations in the low 1014 cm−3 range are quantified by means of highly sensitive resistance measurements. GaH pairs are generally found to form faster than BH pairs. Arrhenius analysis shows a difference in activation energy (BH: 1.20 eV, GaH: 1.04 eV) while the trial frequency is the same (≈4×108 s−1). [ABSTRACT FROM AUTHOR]

There are similarities between the growth processes of ingot crystalline silicon with different sizes, so the growth law of small size crystals could be transferred to large size crystals. In this paper, transfer learning (TL) was used to design the hot zone of the G8 ingot furnace. The design targeted parameters are the positions and volumes of the side and top heaters, and the height of the partition block on the side insulation cage. The main design goals are to reduce the dislocation defects inside the crystal, suppress polycrystalline at the edge of the silicon ingot and make the solid-liquid interface slightly convex. First, a neural network was used to establish a mapping model between the hot zone geometric parameters and hot zone evaluation parameters for the existing G7 ingot furnace. Then the model was transferred to the G8 ingot furnace. The effects of different model structures on the transfer process were analyzed. Then Dropout was used to determine whether the model is overfitting. The genetic algorithm (GA) and the clustering algorithm (CA) were applied to optimize the hot zone geometric parameters. The above is the process of G8 hot zone design. Finally, the numerical simulation method was used to study the temperature distribution and solid-liquid interface shape of the optimized schemes. The final selected scheme could achieve high quality crystal growth. Then the scheme was applied to the hot zones of G7 and G8 furnaces. The results show that the axial temperature gradient of G8 in silicon melt and silicon crystal is smaller than that of G7, and the radial temperature gradient at the solid-liquid interface is also smaller than that of G7. It is beneficial to reduce the thermal stress inside the crystal. [ABSTRACT FROM AUTHOR]

Abstract Crystalline silicon tandem devices with perovskites, CIGS, and nanocrystalline silicon, as well as the TOPCon design, are incompatible with the conventional pyramidal surface texture of silicon. This is a result of crack formation in nano to polycrystalline growth on large sharp surface features. In this work, three texturing approaches are investigated, using alkaline and/or acidic wet chemical etches, that can lead to the crack‐free growth of nano to polycrystalline materials on textured surfaces. In this work, we show that without acidic smoothening, the fraction of pyramidal surface coverage has to remain relatively small to prevent crack formation during crystalline growth on these surfaces. Applying an acidic etch as a function of time continuously smoothens surface features. This shifts the reflection to wider scattering angles and results in higher total reflected intensity with respect to the conventional texture, making it an interesting option for a wide variety of tandem pv applications. Finally, we demonstrate crater‐like features on a monocrystalline silicon surface using an etching process including a sacrificial layer. These craters increase light scattering into wider angles, but to a lesser extent than the former approach. In terms of passivation, we demonstrate the positive effect of a post deposition hydrogen treatment. Initial dilution of the silane plasma improves passivation on a surface, but is detrimental to passivation on a surface, likely because the hydrogen dilution results in epitaxial growth at the c‐Si/a‐Si:H hetero‐interface. A minority carrier lifetime of over 3 ms has been achieved for all texturing approaches, after deposition of a 15 nm a‐Si:H layer on both sides of the wafer, for different a‐Si:H deposition and annealing schemes.