Search

Perovskite/crystalline-silicon (c-Si) tandem solar cells offer a viable roadmap for reaching power conversion efficiencies beyond 30%. In this configuration, however, the silicon cell now mainly receives an infrared rich illumination spectrum where the absorption coefficient of silicon is poor. To boost the light absorption in this wavelength interval, transmitted through the top cell, a solution is to introduce a dedicated nanoscale texture on the front side of the silicon bottom cell and tweaking the optical elements in its design. These optical elements are manifold, with tunable geometrical dimensions, layer thicknesses, and refractive indices. For optically optimizing nanostructured silicon solar cells, electromagnetic wave solving methods, such as the rigorous coupled-wave analysis (RCWA), are normally used but they become computationally infeasible when several design variables are involved in an optimization problem. In this work, a natural selection algorithm, known as the genetic algorithm, is coupled with RCWA for extracting the optimal values of various design parameters in four-terminal perovskite/c-Si tandem devices in parallel. Both two-side-contacted and interdigitated back-contacted silicon heterojunction cell structures, featuring an inverse nanopyramid grating texture on the front, are optimized for five interdependent variables using a genetic algorithm for the bottom cell application and benchmarked against their random pyramid textured analogs. Our study shows that an optimized inverse nanopyramid grating texture can outperform the standard random pyramid texture when considering incidence angle variations. More importantly, the study illustrates how a genetic algorithm can support modeling complex solar cell structures with numerous degrees of freedom.

The two-step implantation of argon precursor ion (Ar+) followed by boron ion (B+) in single crystalline silicon at room temperature is discussed to activate boron implanted region by post heating at 300 followed by 400°C. The implantation of Ar+ at a dose of 6.0 × 1013 cm-2 at 70 keV with a projected range Rp(Ar) of 80 nm followed by B+ at 1.0 × 1015 cm-2 and 15 keV with Rp(B) of 62 nm caused crystalline disordered states with the effective disordered amorphous depth Aeff of 32 nm, while the post heating of 300°C for 90 min followed by 400°C for 30 min markedly decreased Aeff to 1.8 nm. The effective recrystallization by the post heating promoted activation of doped region associated with decrease in the sheet resistivity to 189 Ω/sq by the post heating. The activation ratio was estimated as 0.33 under the assumption of a hole mobility of 50 cm2/Vs in the boron implanted region.

We present a methodology where we combine numerical TCAD device modeling, machine learning and advanced statistics for getting a deeper understanding of how process variations influence device performance in mass produced crystalline silicon solar cells. For this, we use seven model input parameters that affect the mainstream solar cell design (PERC) and its performance the most and perform about a couple of hundred numerical TCAD device simulations in an expected range of these parameters. As such detailed numerical simulations take long time, we train and validate machine learning models on these simulations, which serve to describe ten thousands of fabricated PERC cells. The method gives concrete information for improving PERC cells with a modest amount of numerical modeling and hence in a very short time. This approach is not limited to a specific solar cell design or product.

This paper discusses different parameters and their effects on the efficiency of a crystalline solar cell. This is done using a 1D Drift Diffusion model for silicon solar cells by varying several parameters like the n-layer and p-layer thickness, electron and hole doping concentration, the electron and hole maximum SRH lifetime, and electron-hole saturation velocity. A various permutation of the values of these parameters was used to study various characteristics of the solar cell and calculate the maximum efficiency. It investigated various output characteristics to understand the correlation between these input parameters and the efficiency of solar cells. Simulating graphs such as current and power vs voltage, band diagrams helped us in getting optimum input parameters to achieve maximum efficiency. The paper presents, as motivation for this work, a number of parameters that can be used to increase the efficiency of a solar cell, which is a fundamental unit of a solar panel, which in turn can be a stepping stone to move towards a cleaner energy source. The efficiency of the solar cell peaked when the n-layer and p-layer thickness took $3\ \mu \mathrm{m}$ and $55\ \mu \mathrm{m}$ values respectively, while the ideal SRH lifetime for a crystalline silicon solar cell was measured to be 10−2 s. The efficiency achieved for the same was 24.61%. This paper further explores and understands the reasons for these optimums and how and by how much they improve the efficiency of the solar cell.

Carrier selective passivating contacts, which provide dual functions of surface defect passivation and extracting one type of charge carriers, attract attention for realizing high efficiency crystalline silicon solar cells. Hydrogenated amorphous silicon (a-Si:H) has been a key enabler known as the silicon heterojunction (SHJ) technology. Here we pursued novel materials focusing on hole-selective passivating contacts: one is the hydrogenated nanocrystalline silicon (nc-Si:H) and the other is the metal-oxide (non-silicon) material. For the nc-Si:H, it is demonstrated that the use of the $(p)\text{nc-Si:H}/(i)\text{a-Si:H}$ stack instead of the conventional $(p)\text{a-Si:H}/(i)\text{a-Si:H}$ in SHJ solar cells provides not only a mitigation of the parasitic absorption loss but also improvements in passivation and electrical contact properties. This results in an efficiency increase by 0.3-0.6% absolute compared to our reference cell, and a best cell efficiency of 23.5%. For metal-oxide material, we have developed an atomic-layer-deposited titanium oxide ( $\text{TiO}_{\mathrm{x}}$ ) that functions as an efficient and transparent hole-selective passivating contact without using buffer layer, leading to the proof-of-concept solar cells with efficiencies above 20%.

International audience; Irradiation of crystalline silicon with ultrashort laser pulses is a well-known method for creating thin amorphous surface layers. The underlying mechanisms are based on ultrafast melting and rapid quenching of the molten phase, preventing the formation of the crystalline phase. The interest of this method for applications in the electronics industry lies in the very different electrical properties of the amorphous phase obtained. It has also triggered strong attention in the field of silicon photonics, the amorphous phase exhibiting a higher refractive index than the crystalline phase at telecom wavelengths. This simple feature could be exploited for low-loss optical waveguiding in a thin amorphous surface layer, provided the latter is sufficiently thick. However, the maximum thickness of laser-induced amorphous layers reported to date is < 70 nm [1] , which is below the requirements for supporting guided modes.

The installation condition of crystalline silicon (c-Si) solar cell module is limited to using in the urban environment. The arbitrary fittable c-Si solar cell module is the method for overcome the limitation about space and various light condition. By using tessellated structure with origami patterns, it could be rigid folding and easily deformed about the arbitrary surface. Also the metal textile connection has been introduced for stretching the creases between cells by rotating at the cross points. Module has shown not only better performance but energy production under various angles of incident light than conventional module.

This work focuses on a passivating contacts technology for crystalline silicon (c-Si) wafers based on ultra-thin (15nm) poly-crystalline Silicon (poly-Si) on silicon oxide (SiOx) stacks. Combined with standard TCO (Transparent Conductive Oxide) layers in a simplified solar cells fabrication process, photovoltaic (PV) conversion efficiencies approaching 22% are obtained on cast-mono wafers. This technology is also shown to be compatible with different TCO layers, depending on the post metallization annealing step. This so called "High Temperature Silicon Heterojunction" structure is therefore very promising for high efficiency solar cells processes at lower cost.

Potential-induced degradation shunting (PID-s) rapidly develops within a p-type crystalline silicon PV module and detrimentally impacts its performance. This work aims to study the spatial progression of PID-s within mono and multi-crystalline silicon module. PID-s treatment on the test modules was conducted in a climatic chamber. For the investigation of PID-s, pre and post-test images were capture using electroluminescence imaging and dark lock-in thermography. Experimental results show that cell edges and corners are more prone to PID-s formation. Also, pre-existing defects such as recombination centers, cracks play some role in PID-s progression. The performance of the spatial imaging techniques in PID-s investigation is also discussed.

This work compares a recently developed analytical expression for the maximum-power point voltage with experimental data, to test its usability for crystalline silicon solar cells. The experimental data covers measurements from 18 multicrystalline silicon solar cells with different bulk resistivities and cell architectures. We show that the expression is able to predict the maximum power obtainable by the measured cells with relative discrepancies below 1%. Additionally, we compare the accuracy of this new expression with two already existing models.

Potential-induced degradation (PID) significantly affects the performance of a photovoltaic (PV) module. In this paper, modeling and simulation of PID affected module are performed to unveil the insights of electrical losses and stresses resulting under partial shading conditions. PID is modeled using two diode model, taking into account the severity and nature (ohmic and non-ohmic) of PID shunting. Frequently observed shading patterns in a field are considered in the simulation. Results show that the predominantly ohmic nature of PID improves the module output under partial shading conditions, although it also leads to extreme reverse stresses across the shaded cell. In the case of non-ohmic PID, reverse stresses across the shaded cell are not much severe, leading to degradation in module power output. Perpendicular shading pattern to the cell string results in severe power loss, and with an increase in ohmic PID severity, reverse stresses across the shaded cells increase significantly. Failure of bypass diode leads to excess power loss and reverse stresses at shading percentage lower than critical shading.

Light-induced degradation (LID) occurring on mainstream boron-doped silicon solar cells has been investigated for decades. Its relationship with boron and oxygen concentrations in crystalline silicon has made it widely accepted to be the cause of such degradation. Post-fabrication methods have been developed to decrease the impact of its effects on solar cells. However, little is known about the responsible complex composition and its detailed electronic properties, due to the previous lack of a direct spectroscopic method to study its characteristics. In this work, we have applied a combination of lifetime spectroscopy and Deep Level Transient Spectroscopy (DLTS) following the observations of [1], [2] to further our understanding of its formation and dissociation. Our studies have revealed the presence of a newly found energy level on the pre-degraded state of the studied samples, in addition to the level reported in literature. These deep levels have been observed to inversely correlate with the formation and dissociation kinetics of the recombination active BO-LID defect. The results in this work presented therefore suggest that the defect(s) causing LID introduce multiple levels to the silicon band-gap.

The continued reduction in the amount of silver used to decrease the cost of solar energy is applied to a novel grid finger screen printed metallization design. Improved solar cell and solar module performance metrics are increased while reducing the amount of metal needed per solar cell. Just as the current design of busbars has changed to incorporate segmented busbars, floating busbars or no busbars where a multi-wire module is used, the design of grid fingers needs to also evolve to eliminate redundant or unnecessary function within the solar cell device. Using a technology like the Configurable Current Cell that includes a modified "H-Bar" metallization pattern shown in this paper will provide additional methods to reduce the amount of metal needed on the front and rear of a solar cell to optimize the performance of a solar module.

In this work we investigate the characteristics of solar cells cracks in photovoltaic (PV) modules for understanding the extent to which the solar cell electrical parameters change due to cell crack degradation. The experimental investigation is performed on two custom nine-cell mini-modules of mono- and multi-crystalline silicon, respectively, where each solar cell in the module has a junction box, allowing individual and module level characterization. Results show that power loss caused by cell cracks is driven primarily by a reduction of the cell’s maximum power point current, in particular B type cracks. C cracks also affect the short circuit current of the cells, whereas cells with combined B and C cracks show the most reduction of the short circuit current. Equivalent circuit diode model curve fitting and analysis of the light or dark I-V curves proved of limited used in analyzing degradation of cracked cells, as the model assumptions break down. However, a comparative analysis of dark and light I-V curves with a Suns-V oc curve was better suited for understanding the evolution of diode parameters on cracked cells for increasing levels of degradation.

There is no doubt that silicon-based solar cells provide continuous power to space vehicles, but exposure to high-energy particle irradiation and large temperature differences are two challenges. In this report, the temperature effects of the crystalline silicon-based solar cells are experimentally evaluated by the short-circuit current and open-circuit voltage at a scope of 10-300K. The test PV device is named as semiconductor – quasi – insulator - semiconductor (SQIS), which is fabricated by a direct sputtering deposition of ITO film on crystal Si substrate clad with reactive grown a-SiOx(In), an indium-contained hybrid oxide layer.

High voltage photovoltaic (PV) systems are affected by potential induced degradation (PID). PID detection by conventional data analysis methods could take a long time, leading to unnoticed energy loss. If PID is detected at an early stage, energy loss could be avoided by taking appropriate measures. This paper presents a new method for detecting PID at an early stage (< 1% power loss). The method is based on low-current DC signals and, hence, it could be implemented in a low-cost sensor. The method was tested experimentally on standard multi-cell crystalline silicon PV modules and successfully detected PID before 1% power loss.

The ions generated from electrochemical reactions among packaging materials have a significant effect on the performance of solar module in the power plant. In this paper, the origin of ions for crystalline silicon solar module under high system voltage was investigated. It was found that there exist different ions in module under different polarity system voltage. These generated ions could reduce the adhesion strength of packaging materials and leads to delamination of module. Especially, the generated ions under negative bias could lead to insulation failure and PID. The obtained results are beneficial to understand the performance of solar module in the field.

Lightweight crystalline silicon (c-Si) PV modules with a weight of 5kg/m2, by substituting the typical front glass with a thin polymer sheet and the standard back sheet by a composite sandwich structure are presented here. With this work, we propose the use of a "combi-encapsulant", as a front sheet for the proposed lightweight composite PV modules. With the final goal of manufacturing a lightweight structure able to withstand environmental and mechanical stress tests (following the IEC 61215 [3]), as combined sequential tests.

Optimally prepared industrial n-type TOPCon c-Si bifacial solar cells (156 mm × 156 mm) fabricated with cost-effective screen-printable front-side and rear-side metallization pastes had a median solar cell efficiency of 22.19 ± 0.10% and bifaciality Eff factor of 82.3%. A front-side paste comprising silver, metallic aluminum, and inorganic frit was designed to contact p+ boron-diffused Si emitter surfaces with SiN x : H-Al 2 O 3 antireflection-passivation layers. A rear-side paste comprising silver and inorganic frit was designed to contact n+ phosphorous-diffused Si surfaces with tunnel-SiO x /n+poly-Si/SiN x : H layers. Solar cell electrical data suggests efficiency is being limited primarily by the front-side metallization paste. The final front-side metallization microstructure shows isolated metallic aluminum particles surrounded by solidified glass within the bulk sintered silver conductor line. The front-side conductor metal-p+ boron-diffused Si emitter contact region shows continuous interfacial films decorated with silver colloids located between the bulk conductor metal and Si emitter surface. A microstructural model suggests electrical contact for the front-side contact region occurs by a tunneling mechanism though the residual interfacial films.

When cells in a crystalline silicon photovoltaic module crack, packaging materials hold the fragments together. Changes in module temperature cause cell fragments to move, allowing cracked metallization to lose and regain contact. We intentionally cracked cells in commercial PV modules and characterized the modules’ temperature-dependent electroluminescence (EL) response. Here we show that (1) metallization makes contact across cracks in a way that is temperature dependent and (2) this contact is not a function of temperature, but is hysteretic. We expect that any electro-optical characterization made at a single temperature will be misleading as to the effects of cracked cells at different temperatures. And we expect that a single temperature sweep cannot fully characterize the temperature dependence of electro-optical performance of modules with cracked cells.

Metallization plays a very important role in fabricating low cost and high efficiency silicon solar cells. Silver (Ag) metallization of industrial crystalline silicon (c-Si) solar cells comprises a large share of the total cell production cost. However, in amorphous silicon based (a-Si:H) c-Si heterojunction solar cell (SHJ) fabrication, the metallization process costs more compared to the metallization process for traditional crystalline silicon (c-Si) solar cells since it requires expensive, low temperature Ag pastes [1]. These specialized, low temperature Ag pastes are required because the passivation quality at the a-Si:H(i)/c-Si interface degrades if annealed at temperatures above 200°C. This temperature limitation not only increases the fabrication cost, but also results in poor sintering of the metal contacts which increases the resistive loss [2]. In this work, we introduce a novel Ag metal contact printing technique for SHJ solar cells using a Ag nanoparticle ink and an in-line laser sintering process with the goal of reducing the bulk resistivity of the printed Ag without requiring any ex situ annealing. In this process, the Ag nanoparticle ink is dispensed through a very small diameter needle on the SHJ substrate with simultaneous sintering using a focused continuous carbon dioxide (CO 2 ) laser beam. We have been able to print Ag lines with width as low as 50 µm and bulk resistivity as low as 8 µΩ·cm using this printing technique.

In this work, we explore the influence of module size on the rate of interconnect solder bond thermomechanical fatigue (TMF) damage and the probability of cell fracture. For the solder bond TMF damage evaluation, structural mechanics models of crystalline silicon PV models are created to solve with the Finite Element Method. For the probability of cell fracture evaluation, Weibull analysis and weakest link theory are employed to resolve the probability of crystalline silicon PV cell fracture when measured as bare cells and when stressed in reduced- and full-sized modules. Results conclusively demonstrate that the rate of solder bond TMF damage is independent of module size, interconnect location across the cell and cell location across the module and that smaller, representative, modules must be loaded to a much higher level than their parent full-sized modules to achieve an equivalent driving force for cell fracture.

With silicon heterojunction (SHJ) solar cells at their practical efficiency limit, their long-term reliability and stability remains the hindering block toward mass adoption. Precisely, it is the degradation of passivation over time under field operating conditions at amorphous silicon (a-Si:H) and crystalline silicon (c-Si) interface that is a concern. Therefore, we investigate the passivation quality of a-Si:H/c-Si in terms of interface defect and charge density by extracting surface recombination velocity (SRV) using the temperature- and injection- dependent lifetime spectroscopy technique. Our results show passivation quality of the interface degrades at elevated temperature due to thermally activated defects at the surface. Moreover, temporal dependence of a-Si:H/c-Si interface passivation shows degradation due to increase in SRV originating from failing chemical passivation exhibited by an increase in defect density at the interface. Interestingly, field passivation seems to remain the same through the time of these experiments.

This paper proposes a field aged indoor testing (FAIT) procedure for technical stakeholders in photovoltaic industry to test outdoor exposed modules. It uses non-destructive, indoor methods to investigate weather-induced degradations to ensure reliability of modules operation. It discusses several techniques including current-voltage (I-V) curve measurements, electroluminescence (EL), Infrared (IR) and ultra-violet (UV) imaging, visual inspection, quantum efficiency (QE) measurements, and insulation resistance tests. The paper discusses the different defects and degradations that can be characterized using the proposed techniques. It also includes discussion on the test prerequisites, preparation of modules, testing conditions, test input parameters, and basic post-processing of data.

We experimentally proved an effective use of UV-ozone oxide layer in junction passivation and current tunneling applications of crystalline silicon (c-Si) solar cells. The UV-ozone generated oxide layer can improve the passivation quality of aluminum oxide(AlO x ) when inserted between the silicon wafer surface and atomic layer deposited(ALD) AlO x . When tested on junctions that moderately diffused by phosphorus and boron (sheet resistance R sh ~110 Ω/□), the UV-ozone oxide and AlO x stack resulted in a J 0 no more than 12fA/cm2. The same oxide layer is also considered as a passivating contact material. When applied as an interlayer between diffused silicon surface and aluminum contact, the passivated contact structure realized a contact resistivity (ρ c ) of ~ 1mΩ-cm2 and ~ 25mΩ-cm2 for boron and phosphorus passivating contact structures, respectively, with moderately doped diffusions.

The use of solar energy in the world's electrical systems has been increasing significantly in recent years, reaching 750 GW cumulative in 2021. New challenges and modes of degradation in photovoltaic modules appear mainly due to the different working and climatic conditions of the installation sites. In the last decade, a cell defect, termed snail trails, has been reported. These irregular dark lines on the surface of crystalline-Si (c-Si) solar cells within encapsulated modules can compromise the power generated, and consequently the return on investment. The objective of this study is to identify and analyze the causes of the snail trails in c-Si PV modules operating for 7 years in Minas Gerais, Brazil. IV-characteristics recorded for the modules showed reduced power output that can be correlated with the microcrack defects that are the origin of the snail trails.

A fully finished, aluminum back-surface field, multi crystalline silicon solar cell was analyzed using Raman microspectroscopy. New insights into the process and material quality of the finished device is obtained. First, the image scan obtained on the multi crystalline silicon surface is reflective of the textured surface contributing to the surface topology. Second, the analysis helps to identify differences in the Raman spectra of the remnant saw marks on the silicon surface when compared to a textured silicon surface. Third, Raman analysis of the silver line shows a clear silver oxide signal that is detected up to 25 μm away from the edge of the silver line thus, quantifying the quality and effectiveness of the screen-printing and firing process. Finally, inclusions embedded inside the silicon surface are unambiguously identified as nanocrystalline silicon. Using confocal Raman microspectroscopy 3D tomography of the inclusions are constructed and the state of compressive stress around these particulates are measured. Taken together, these results demonstrate Raman microspectroscopy as a valuable tool for identification of micron-scale feature sizes and defects, otherwise too small to be identified using current metrology techniques.

Power generation for the Internet of Things (IoT), particularly wearable electronics, is a significant challenge and a subject of great interest in the field of photovoltaics research. Here, we have designed and fabricated single crystalline silicon solar cells using a single-sided micromachining process. Preliminary results indicate that the solar cell is flexible and ~50% transparent. Furthermore, the open-circuit voltage and the short-circuit current density of the fabricated device under indoor light with the power density of 2 mW.cm-2 are 0.4 V and 110 µA.cm-2, respectively. The fabricated solar cells have been specifically designed to conformally fit on the commercial contact lenses.

Potential-induced degradation is a disastrous failure mode of crystalline silicon solar module. This phenomenon can be reflected by deterioration of ideality factor. In this paper, ideality factor of PID-free and PID-affected silicon solar module were investigated under different irradiances. It is found that the ideality factor of PID-affected solar module is larger than that of PID-free solar module at the same irradiance. The obtained result indicates that the ideality factor of PID-affected solar module is more sensitive than that of PID-free solar module when injection level increase from 700 w/m2 to 1200 w/m2.

In this paper, silicon nanowires formation on N-type crystalline silicon wafer is studied. Metal-assisted chemical etching (MACE) technique is used in this study because it’s low cost but can produce a high-aspect-ratio of silicon nanowires. High-aspect-ratio silicon nanostructures have been proved as an effective texture for light trapping on silicon solar cells surfaces. The photons from incident light can be trap on the silicon nanowires and then being absorb into the cells which resulting high efficiency silicon solar cells. Traditionally, MACE works by creating a holes using metal catalyst such as Ag or Au in order to reduce of the etchant. The hydrofluoric acid (HF) and hydrogen peroxide (H 2 O 2 ) are function to etched the metal native oxide thus create a pores or nanowires formation. Roughness parameters of silicon nanowires was investigate in order to see the texture of silicon nanowires is rough enough to trap more photons on silicon wafer surfaces. Hence, roughness parameters are very important for texturing silicon wafer surfaces. In this study, root mean square (RMS) is used as an indicators for which acquired from the line profiles. Results from the roughness parameters shown a good compatibility.

High-efficiency silicon solar cells requires an effective carrier selective contact. Over the past few years, molybdenum trioxide (MoO3) has been widely used as the hole selective contact (HSC) for silicon heterojunction solar cells. The high work function and wide energy gap lead to favorable band bending for hole transport across the MoO3/Si interface. In previous studies, the MoO3 is commonly deposited by thermal evaporation. Here, we propose a simple solution-processed method to form a MoO3 HSC for conventional crystalline silicon (c-Si) solar cells. The crystalline MoO3 nanoparticle solution with a concentration of 2.3-2.7wt% was blade coated on the rear side of an n+/p silicon solar cell without an antireflective coating. By measuring the current-voltage (I-V), contact resistivity (ρ c ), and external quantum efficiency (EQE), we investigate the photoelectric properties of the solar cells incorporating the MoO3 nanoparticle layer. We show that the MoO3 HSC has a low contact resistivity of 29.5 mΩ cm between p-type Si and the silver electrode. The EQE exhibits enahcement on the near-infrared wavelength regime, indicating a field passivation effect. Overall, the n+/p c-Si solar cell incorporating the solution-processed MoO3 HSC exhibits an improved power conversion efficiency (PCE) of 11.8% due to an increased open-circuit voltage (Voc) and fill factor (FF).

We developed and applied an improved theoretical model to optimize characteristics of highly efficient textured solar cells (SCs). The model accounts for all recombination mechanisms, including nonradiative exciton recombination and recombination in the space-charge region (SCR). To compare the theoretical results with an experiment, we proposed empirical formula for the external quantum efficiency (EQE), which describes its experimental spectral dependencies near the absorption edge. The proposed approach allows modeling short-circuit current and photoconversion efficiency in the textured crystalline silicon solar cells. The theoretical results, compared to the experimental measurements, were used to optimize the key parameters of the SCs, such as the base thickness, doping level and others.

Back-contact solar modules made with crystalline silicon cells are, to-date, amongst the highest peak power density devices on the market and are predicted to retain this status in the coming years. One of the barriers to mainstream adoption of this technology was for some time the availability of reliable supply of conductive backsheet, back-contact solar cells and back-encapsulants, which has been addressed for some years now. Still the industry is continuously searching for better and cheaper bill-of-materials, however the introduction of these materials is very time-consuming as quite some accelerated ageing tests are needed to certify the solar modules, typically over a period of 5-6 months. In this study, three different methods have been investigated, showing a similar ageing profile achieved in a shorter timeframe. The first method is the use of a single-contact solar device, which is much more sensitive during ageing and thus gives a quicker indication of changes in material properties. The second method is the use of a thermal shock chamber instead of thermal cycling. The third method makes use of damp-heat testing at elevated temperatures.

We apply NAnocrystalline Transport path in Ultra-thin dielectrics for Reinforced passivating contact (NATURE contact) to crystalline silicon solar cells for simultaneous achievement of passivation and carrier extraction. The Si nanocrystals are formed in silicon oxide by deposition of hydrogenated amorphous silicon oxide with different oxygen concentration and subsequent annealing. NATURE contact with total layer thickness of 8 nm exhibits reasonably good passivation performance. Furthermore, we demonstrate that NATURE contact can be successfully implemented to the both sides of crystalline silicon solar cells. NATURE contact, which permits flexible structural and chemical design of a passivation contact layer, will open a possibility for various functional devices.

The working temperature of solar module has a significant effect on the performance. In this paper, the effect of temperature on ideality factor for PERC monofacial solar module was investigated based on single-diode equivalent circuit modelling. It is found that the ideality factor of PERC monofacial solar module decreases with the increasing temperature under different irradiances. The non-ideal behaviour can be reflected in deviation of the ideality factor from unity and its temperature dependence.

Doped polycrystalline silicon (poly-Si) passivating contacts featuring a thin tunneling oxide have emerged as one of the most promising carrier selective contacts for crystalline silicon (c-Si) solar cells due to their very low recombination and resistive losses, as well as a high thermal stability compared to amorphous silicon (a-Si:H) heterojunctions. This contact technology consists of a heavily doped poly-Si layer on top of a c-Si substrate with an interfacial ultra-thin silicon oxide layer (SiO x ). To implement poly-Si passivating contacts into an industrial silicon solar cell production line, a cost-effective and high-throughput deposition process is required. Atmospheric pressure chemical vapor deposition (APCVD) process is a single side deposition process that requires no vacuum or plasma systems and is very well suited for high volume manufacturing. In this work, we present an in-line APCVD process for depositing heavily phosphorus doped poly-Si films to form low recombination electron contacts using silane (SiH 4 ) and phosphine (PH 3 ) as precursor gases. The as-deposited samples went through different post deposition annealing processes for solid phase crystallization, dopant activation and dopant diffusion. We have studied the effect of different process parameters like deposition temperature, precursor gas ratio and different post deposition treatments etc. on the surface passivation quality of this contact.

The interplay of boron-oxygen related defect dynamics and temperature dynamics under intense illumination is addressed by means of simulations. Especially the impact of intensity on injection and temperature on cell level is discussed. Furthermore, it is exemplarily shown how the regeneration process can be optimized numerically.

The roadmap for the development of silicon solar cells requires the introduction of passivating contacts to obtain higher efficiencies as well as to reduce the cost of production to be industrially implemented. In this context, Laser Fired Contact (LFC) on p-type silicon wafers have been shown to be an effective technique to improve efficiencies, due to their ability to reduce recombination losses on the back surface of crystalline silicon solar cells. These studies have mainly focused on high quality monocrystalline silicon wafers and there are not enough developments made with multicrystalline silicon (mc-Si) wafers. Therefore, in this work, we present the optimization of the LFC process on p-type mc-Si and its application to two types of silicon devices: diffusion and heterojunction solar cells. These rear contacts have led to improved efficiencies for both types of solar cells over similar devices with thermalized aluminum rear contacts and without back passivation. These results illustrate the enormous potential of these localized laser-contacts created for mc-Si solar cells, perfectly compatible with a lower cost industrial production.

In view of the destruction of the natural environment caused by fossil energy, solar energy, as an essential technology for clean energy, should receive more attention and research. Solar cells, which are made for solar energy, have been quite mature in recent decades. This paper reviews the material properties of monocrystalline silicon, polycrystalline silicon and amorphous silicon and their advantages and disadvantages from a silicon-based solar cell. The follow-up fabrication of silicon solar cell can be divided into two types: crystalline silicon wafer composed of monocrystalline polycrystalline silicon wafer and thin film silicon wafer. The further application of solar cells is inseparable from their material and manufacture. Therefore, this paper also discusses the various ways of applications of the diverse types of solar cells.

The present article describes the process of Metal Assisted Chemical Etching to produce a nanowire structure on the multicrystalline silicon surface by using silver metal catalyst. From the surface morphology (SEM) it has been observed that the produced nanowire structure of diameter ≈ 10 nm and having average length of 80 nm and 100 nm approx. has been formed for the process time 60 seconds and 120 seconds respectively. From the reflectance measurement it has been observed that the silicon nanowire provides a degree of reflectance of 5% to 8% over a spectrum range of (300 to 1000) nm.

The actual operating conditions of solar photovoltaic (PV) modules in external environments are generally very different from those presented at STC (Standard Test Conditions) provided by the manufacturers; therefore, it is important to evaluate the solar PV module's operation in real outdoor environments and verify how their performance is affected by variables such as temperature, humidity and irradiation. In this article two stand-alone PV systems with monocrystalline and polycrystalline silicon technologies, with a data acquisition system were designed and implemented, in order to take measurements of environmental variables and power output. A three-month study between September and November 2019 in Bogota was done, obtaining measurement data in order to compare environmental variables versus power output. The results obtained in this study show the relation between the environmental conditions and the power output for different PV module technologies.

This work reports a novel design for high-frequency piezoelectric gyroscopes using support transducer which enables an efficient energy coupling from a length-extensional mode into a degenerate secondary elliptical mode (n = 3). The gyroscope structure is made by a single crystalline silicon (SCS) disk supported by eight-transducer arms. Large drive mode displacement is excited through piezoelectric AlN thin films on transducer arms. The simulation of the proposed gyroscope shows a high scale factor of 12.24 nA/°/s at resonator Q of 10,000 in a mode-matched condition. The device was fabricated using the PiezoMUMPs process with 10 μm thick silicon structural layer. The fabricated gyroscope shows that the frequency split between drive and sense mode is only 600 Hz at the mean resonant frequency of about 9.976 MHz in air (equivalent to 60 ppm), verifying our design efficacy. The measured scale factor of the proposed gyroscope is around 54.01 μV/°/s before demodulation.

It is shown here that silicon (Si) based solar cells can be deposited by physical vapour deposition (PVD) methods only. These cells are called the PVD-Si cells. Their processing eliminates the deposition methods involving high temperature processing steps, and / or expensive, toxic and flammable gases used for processing conventional solar cells with Si absorbers. The PVD-Si cell design investigated has the structure of ITO | MoOx | c-Si | LiF | Al. When this cell is deposited on an untextured crystalline (c-Si) wafer, it has a fill factor value of 81.6% under the standard test conditions (STC). In order to improve the amount of short-circuit current density (Jsc) generated, this cell is also demonstrated on a textured c-Si wafer, achieving Jsc of 35.94 mA/cm2 under STC.