Efficiency Of Silicon Solar Cells Research Articles

Tuning work function and surface-modified AZO films on FTO substrate to improve the efficiency of thin-film silicon solar cells

Tuning work function and surface-modified AZO films on FTO substrate to improve the efficiency of thin-film silicon solar cells

Modeling of characteristics of highly efficient textured solar cells based on c-silicon. The influence of recombination in the space charge region

Theoretical modeling of the optical and photovoltaic characteristics of highly efficient textured silicon solar cells (SC), including short-circuit current, open-circuit voltage and photoconversion efficiency, has been performed in this work. In the modeling, such recombination mechanisms as non-radiative exciton recombination relative to the Auger mechanism with the participation of a deep recombination level and recombination in the space charge region (SCR) was additionally taken into account. In a simple approximation, the external quantum efficiency of the photocurrent for the indicated SC in the long-wavelength absorption region has been simulated. A theory has been proposed for calculating the thickness dependences of short-circuit current, open-circuit voltage and photoconversion efficiency in them. The calculated dependences are carefully compared with the experimental results obtained for SC with the p+-i-α-Si:H/n-c-Si/i-n+-α-Si:H architecture and the photoconversion efficiency of about 23%. As a result of this comparison, good agreement between the theoretical and calculated dependences has been obtained. It has been ascertained that without taking into account recombination in SCR, a quantitative agreement between the experimental and theoretical light I V characteristics and the dependence of the output power in the SC load on the voltage on it cannot be obtained. The proposed approach and the obtained results can be used to optimize the characteristics of textured SC based on monocrystalline silicon.

Analysis of different printing technologies for metallization of crystalline silicon solar cells

Abstract Crystalline silicon solar cells have been the workhorse of the Solar Photovoltaic industry, contributing to >90% of the total installations. The fabrication of solar cells involves multi-process steps i.e. chemical treatment, diffusion, passivation and metallization. Among these process steps of solar cell manufacturing, metallization is the most critical one since it not only influences cell performance but also the cost of manufacturing to a great extent. A proper metallization process essentially helps in reduction of various electrical and optical losses. A lot of research is being carried out on various metallization technologies to arrive at an efficient, cost-effective solution for contact formation. Screen printing, flexographic printing, laser metal sintering and recently developed 3D printing are some of the technologies of interest in this field. While 3D printing, laser metal sintering, etc. are still at lab level, flexographic and gravure printing are in search of a suitable paste which can make the technology production-worthy. It is the screen-printed technology of solar cells that currently dominates the commercial market because of its low production cost and process simplicity. Amongst the several technologies that have been developed till date for cell metallization, the screen-printing technology promises to be the most reliable, rugged and production-worthy technology. In this paper, different metallization technologies viz. screen printing (conventional, knotless), stencil printing, light induced plating, metal sintering, flexographic printing, aerosol printing etc. used for contact formation in high efficiency silicon solar cells have been reviewed.

Aeolian dust distribution, elemental concentration, characteristics and its effects on the conversion efficiency of crystalline silicon solar cells

Exposure of PV modules to ambient environmental conditions like dust deposits, has some deleterious effects on peak power (Pmax) and overall conversion efficiency (η). This study investigates the effect of module height, tilt, and orientation on the rate of dust deposition on the surfaces of PV modules. Consequently, the effect of different dust categories on Pmax and η are investigated. North facing module surfaces are observed to exhibit higher deposition rates in southerly winds. A significant decrease in conversion efficiency of 1.30%, 1.74%, 4.05%, 2.74% and 1.38% after a fortnight are observed in modules installed in five randomly selected study sites. A higher decrease in efficiency on average after a fortnight is observed in sites having traces of anthropogenic particles on dust samples collected from the PV surfaces with minimal effects observed in sites having biogenic and geogenic particles. Abundance of anthropogenic dust particles coupled with mild tilt and leeward orientation led to a higher maximum power and efficiency degradation rate.

Simulation of Anti-Reflective TiO2/SiO2 Coating for Silicon Photovoltaic Application by Ray Tracing

n solar systems, anti-reflective coatings are used to reduce reflection and increase efficiency. However, the front surface on the solar cells alone is not effective because most of the light from the sun is reflected and very less energy absorption into the solar cells occur. An anti-reflective coating (ARC) of a sufficient thickness can greatly reduce front surface reflectance. Nanoscale surface texturing, on the other hand, can efficiently capture a higher ratio of incident light to boost optical absorption. In this study, the light trapping scheme within the wavelength of 300 to 1200 nm was used to improve the overall efficiency of silicon solar cells. A thin layer of TiO2 and SiO2 anti-reflective coating with different thicknesses was stacked alternatingly due to their different refractive index with TiO2 having a high refractive index and SiO2 with a low refractive index. Solar irradiance spectrum AM1.5G at normal incidence was used in this present work. For the ray-tracing simulation, the front planar with multilayer ARC with different thicknesses were investigated to obtain the optimum value for optical properties and current density. All the four combination arrangements of SiO2 and TiO2 were evaluated and the maximum potential photocurrent density (Jmax) was calculated. The Jmax value of thin crystalline silicon, c-Si (without ARC) was 24.93 mA/cm2 and increased to 30.28 mA/cm2when ARC was used on the front surface. This represents an increasing of 21.46 % enhancement compared to the Jmax of the c-Si reference. Simulation of Anti-Reflective TiO2/SiO2 Coating for Silicon Photovoltaic Application by Ray TracingImran Al-Haqeem Bin Jaffar1, Siti Hajar Mohmad Salleh2*, Mohd Zaki Mohd Yusoff31,2Faculty of Applied Sciences, Universiti Teknologi MARA, Cawangan Perlis, Campus Arau, 02600 Perlis, Malaysia3Faculty of Applied Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia*Corresponding author’s E-mail: sitiha2902@uitm.edu.myReceived: 08 August 2022 Accepted: 17 February 2023Online First: 17 March 2023

Efficient silicon solar cells with highly conductive zirconium nitride electron-selective contacts

Efficient carrier transport and suppressed interface recombination at back contact are essential for high-efficiency solar cells. Herein, we developed a zirconium nitride (ZrN) film with a low film resistivity of 1.6 × 10−4 Ω cm as an electron-selective contact for n-type silicon solar cells. Suitable band alignment of the n-Si/ZrN hetero-contact eliminates the interface barrier between Al and n-Si. Meanwhile, electrostatic potential induced by interfacial Si–O–Zr bonds assists electron extraction. The fill factor of devices has been significantly improved by incorporating a ZrN layer. After optimizing the thickness of ZrN and contact fraction, the champion ZrN-based device exhibited an efficiency of 19.7%, yielding a 23% enhancement compared with that without a ZrN interlayer.

ZnO antireflection coating on solar cell to increase the efficiency by enhancing optical properties

In today's world, solar cell efficiency is an important concern. Anti-Reflection Coating serves a critical function in increasing solar cell efficiency. The efficiency of a solar cell is influenced by a variety of factors. The key issue here is reflectivity. Antireflection coatings are used to minimise the solar cell's reflectivity. AR coating is done using semiconductor materials. Generally, the reflectance of solar cells can be reduced up to 3.2% by using an Anti-reflection coating. In this experiment, ZnO is employed as an antireflection coating on the solar cell using the spin coating process. After coating, the solar cell is allowed to cure at a rapid rate of evaporation to get a thin film. UV-Spectrophotometer and Solar Simulator are used to investigate the coated solar cell's optical and electrical features. When the results are compared to the efficiency of a bare silicon solar cell, the coated cell outperforms the unprotected solar cell by 4%.

Chain pyramid texturization for better light trapping and efficiency of silicon solar cells

Chain pyramid texturization for better light trapping and efficiency of silicon solar cells

Effect of Molybdenum Disulphide Thin Films on Enhancing the Performance of Polycrystalline Silicon Solar Cells

This research work focuses on augmenting the power conversion efficiency of the polycrystalline silicon solar cell with the aid of antireflection coating (ARC) of synthesized molybdenum disulphide (MoS2). The sol-gel technique and electrospraying method were preferred for synthesizing and depositing MoS2 as transparent thin films on the surface of the solar cells. The optical, electrical, structural, and thermal properties of the coated solar cells were analyzed for understanding the influence of the MoS2 coating. Five different samples (A-II, A-III, A-IV, A-V, and A-VI) were coated with varying coating time. Among them, 120 min coated sample experienced a maximum power conversion efficiency (PCE) of 17.96% and 18.82% under direct sunlight and neodymium light with resistivity as low as 2.79 × 10 − 3 Ω − cm . The investigation of optical properties of the coated solar cells revealed a maximum transmittance of 93.6% and minimum reflectance of 6.3%, achieved for A-IV sample in the visible UV spectrum. Sample A-IV showed prominent results in the temperature analysis with temperatures as low as 38.9°C in uncontrolled and 43.2°C in controlled source environments. The results from various analyses proved that MoS2 was an appropriate material for an antireflection coating to enhance the performance of polycrystalline solar cell.

Advanced carrier lifetime analysis method of silicon solar cells for industrial applications

Over the last few years, the silicon photovoltaic industry has been searching for efficient technologies to reduce the cost of cost/Wpeak by improving their conversion efficiency. However, with the silicon solar cell efficiency approaching the theoretical limit, it has become important to increase the efficiency distribution of cells by managing the loss factors existing in the production process. Although some companies are managing the efficiency distribution through in-line analysis equipment, a preventive action for reducing process defects has not yet been accomplished. To prevent process defects in advance, big data management is required to correlate the process conditions and solar cell parameters. Hence, an analysis method that can simply evaluate the detailed properties of completed solar cells is a key technique in future PV industries. In this paper, we introduce an advanced injection-dependent carrier lifetime analysis logic that can subdivide detailed recombination factors by fitting the carrier lifetime graph obtained through Suns-Voc measurement with a theoretical graph. The industrial applicability of this analysis method was tested with 160 commercially manufactured solar cells, demonstrating the expected quantitative gains of low-efficiency solar cells. The results show that the proposed method helps in determining the process priority for improving the efficiency distribution and provides a research direction for increasing the absolute efficiency.

Efficiency Improvement of Industrial Silicon Solar Cells by the POCl3 Diffusion Process

To improve the efficiency of polycrystalline silicon solar cells, process optimization is a key technology in the photovoltaic industry. Despite the efficiency of this technique to be reproducible, economic, and simple, it presents a major inconvenience to have a heavily doped region near the surface which induces a high minority carrier recombination. To limit this effect, an optimization of diffused phosphorous profiles is required. A "low-high-low" temperature step of the POCl3 diffusion process was developed to improve the efficiency of industrial-type polycrystalline silicon solar cells. The low surface concentration of phosphorus doping of 4.54 × 1020 atoms/cm3 and junction depth of 0.31 μm at a dopant concentration of N = 1017 atoms/cm3 were obtained. The open-circuit voltage and fill factor of solar cells increased up to 1 mV and 0.30%, compared with the online low-temperature diffusion process, respectively. The efficiency of solar cells and the power of PV cells were increased by 0.1% and 1 W, respectively. This POCl3 diffusion process effectively improved the overall efficiency of industrial-type polycrystalline silicon solar cells in this solar field.

Photovoltaics literature survey (No. 181)

Photovoltaics literature survey (No. 181)

Effect of increasing etching time on the efficiency of porous silicon solar cells

In this work, p-type silicon wafers were electrochemically etched to create nanocrystalline silicon (porous silicon (PS)) films. Different etching periods (5, 10, 15, and 20 minutes) were investigated to see how they affected the development of a nanosized pore array with a constant etching current density (10 mA/cm2). To prevent oxidation, PS samples were stored in methanol after preparation. PS is characterized by X-ray diffraction (XRD), and atomic force microscopy (AFM). At varied etching times (5, 10, 15, and 20 min), the crystallite size as determined by XRD was equal to (66.39, 88.13, 31.2, and 21.21) nm, respectively. The nanometric size was verified via AFM. The porosity of PS increased as the etching time increased; the maximum value was obtained at a 20-minute etching time. The C-V characteristic of PS/Si heterojunction describes control factors like built-in potential (Vbi) and the kind of connection, a linear relationship of 1/C2 with bias voltage indicating that the junction is an abrupt type. Vbi was calculated for PS/p-Si/Al heterojunction at different etching times, and it was between (1.1-1.8) volt. I-V characteristics under illumination showed an enhancement in the efficiency of the PS/Si/Al solar cells. The maximum value of the solar cell efficiency was 6.79% occurs at 15 min time of etching.

A Deep-Red Emission Phosphor Y2SrAl4SiO12:Ce3+, Cr3+ and Its Utilization in Polycrystalline Silicon Solar Cells

The power conversion efficiency (PCE) of crystalline silicon solar cells has reached a bottleneck. Further improving the PCE is an important current research topic. This Letter reports a new phosphor Y2SrAl4SiO12:Ce3+, Cr3+. Under the excitation in the wavelength range of 320-650 nm, the phosphor Y2SrAl4SiO12:Ce3+, Cr3+ exhibits a deep-red emission in the 500-800 nm range. Due to the energy transfer from Ce3+ to Cr3+, the luminescence intensity of Cr3+ is further enhanced. This matches well with the spectrum of silicon solar cells. Because of the powerful absorption and high internal quantum efficiency, Y2SrAl4SiO12:Ce3+, Cr3+ was used to prepare energy down-conversion (EDC) films. By applying the EDC film on the surface of silicon solar cells, the relative PCE increases by 2.018%. These results indicate that Y2SrAl4SiO12:Ce3+, Cr3+ is an excellent deep-red garnet structured phosphor and furthermore has a positive effect on the enhancement of the PCE of solar cells.

Study of the Enhanced Efficiency of Crystalline Silicon Solar Cells by Optimizing Anti Reflecting Coating using PC1D Simulation

In this paper, simulation of a mono crystalline silicon solar cell was done using PC1D software. The impact of different solar cell parameters, with their effects on power and efficiency, has been investigated. It is seen that the textured surface reduces reflection and increases the efficiency of the solar cell at least 2–3%. From the simulation, it is seen that the optimum value of p-type doping concentration 1 × 10^16 cm^−3, n-type doping concentration 5 × 10^18 cm with pyramid height of 2–3 μm and equal angles of 54.74 degrees produces the best result in simulation. An anti-reflective coating with a refractive index of 1.38 and a thickness of 84 nm is considered optimal. By optimizing the effective parameters, a solar cell with an efficiency of 24.45% was achieved through simulation. For a p-type mono crystalline silicon wafer, with an area of 10 × 10 cm^2 and a thickness of 200 μm, initial simulation shows a 24.45% efficient solar cell.

Перспективный путь повышения эффективности кремниевых солнечных элементов --- введение нитевидных кристаллов с p-n-переходом

A new approach to increasing the efficiency of silicon solar cells (SCs) is presented, which consists in the creation of surface light-trapping structures with a high antireflection ability in the form of systems of pointed whiskers (NCs) with coaxial p–n junctions. The coaxial geometry of the p–n junction is justified in terms of the efficiency of collection and separation of minority charge carriers (NCCs) due to the built-in electric field across the junction. Received solar cells with improved photoelectric characteristics and an efficiency factor (COP) of 20.43%.

A promising way to improve the efficiency of silicon solar elements --- introduction of whiskers with p-n junction

A new approach to increasing the efficiency of silicon solar cells (SCs) is presented, which consists in the creation of surface light-trapping structures with a high antireflection ability in the form of systems of pointed whiskers (NCs) with coaxial p-n junctions. The coaxial geometry of the p-n junction is justified in terms of the efficiency of collection and separation of minority charge carriers (NCCs) due to the built-in electric field across the junction. Received solar cells with improved photoelectric characteristics and an efficiency factor (COP) of 20.43%. Keywords: solar cell, light absorption, p-n junction, silicon.

SiNx and AlOx Nanolayers in Hole Selective Passivating Contacts for High Efficiency Silicon Solar Cells

The recombination of photogenerated charge carriers at metal-semiconductor interfaces remains a major source of efficiency loss in photovoltaic cells. Here, we present SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> and AlO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> nanolayers as promising interface dielectrics to enable high efficiency hole selective passivating contacts. It is demonstrated that SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> deposited via direct plasma enhanced chemical vapour deposition can be grown controllably at thicknesses of 2 nm. The valence band offsets between crystalline silicon and ultrathin AlO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> and SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> nanolayers are measured as 3.5 and 1.4 eV, respectively. This predicts a larger tunnelling current for holes, compared to SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> used typically. Resistivity measurements show that SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> and AlO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> nanolayers have lower contact resistivities compared to SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> , with values as low as 100 mΩ·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Analysis of the current transport mechanisms confirmed that tunnelling dominates the conduction through SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> , while a mixture of tunnelling and pinholes are present in the AlO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> structure. Lifetime measurements gave initial indications of the passivation quality of the films, with just 10 cycles of AlO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> achieving 260 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> s after annealing and 1.9 ms with extrinsic field effect passivation added. Finally, the intrinsic built-in charge in the dielectrics was determined using surface photovoltage measurements and simulations are used to estimate the influence of nanolayer built-in charge in both poly-Si and dopant-free passivating contacts to enable future high efficiency solar cells.

Modulation of the TCO/MoOx Front Contact Enables &gt;21% High-Efficiency Dopant-Free Silicon Solar Cells

Highly efficient dopant-free silicon solar cell requires effective electron- and hole-selective contacts. We have recently reported a remarkable efficiency of 21.3% for dopant-free silicon solar cells with a low work function and transparent and conductive MgFxOy electron extraction. The transparent conductive oxide (TCO) films and molybdenum oxide (MoOx) front hole contact also play significant roles in the high efficiency of dopant-free solar cells. In this study, zinc-doped indium oxide (IZO), tin-doped indium oxide (ITO), and titanium-doped indium oxide (ITiO) have been deposited via magnetron sputtering at room temperature. The work function and optoelectrical properties of TCO films and energy band bending together with the MoOx layer are investigated. The impact of this band bending on the photoelectrical performances of devices is analyzed in detail as a function of the MoOx/TCO work function mismatch. The optimized IZO film presents the highest work function (5.21 eV) and conductivity (2140 S/cm), resulting in reduced barrier height at the MoOx/TCO interface and enhanced hole-selective transport. The light-soaking treatment is introduced to repair the sputtered damage during the IZO deposition. Finally, an impressive cell efficiency of 21.0%, together with Voc, FF, and Jsc of 712.4 mV, 76.4%, and 38.6 mA/cm2, respectively, shows great potential and provides an effective solution to obtain highly efficient dopant-free silicon solar cells.

Silicon–Hydrogen Bonding Configuration Modified by Layer Stacking Sequence in Silicon Heterojunction Solar Cells

Recent improvements in highly efficient crystalline silicon (c-Si) solar cells have relied on surface passivation. Hydrogen plays a crucial role in the surface passivation of silicon heterojunction (SHJ) solar cells because Si–H bonds passivate dangling bonds in amorphous silicon and on the c-Si surface. In this work, we demonstrate that the Si–H bonding configuration is modified by layer stacking sequence for SHJs. The quality of surface passivation strongly correlates with low-temperature hydrogen effusion from the SHJ structure. Our results show that the deposition of doped layers on intrinsic amorphous silicon supplies additional hydrogen to the amorphous/crystalline heterostructure. Moreover, the deposition of a p-layer modifies the microstructure of the intrinsic layer underneath, whereas depositing an n-layer does not induce structural changes. We suggest that the low-temperature hydrogen effusion characteristics can be used as a sensitive indicator for examining the passivation quality of SHJ solar cells.