Efficiency Of Silicon Solar Cells Research Articles

Effectiveness of the front and rear grids as a result of silicon solar cell metallization patterns: A study using Griddler simulator

The objective of this investigation is to evaluate the effect of metallization patterns on the front and rear grids on the efficiency of the silicon heterojunction (SHJ) cells. Griddler 2.5 PRO simulator was utilized to analyze the effects of various front grid metallization designs and geometries on open circuit voltage (VOC), short circuit density (JSC), fill factor (FF), and efficiency (ƞ) of silicon-based PV cells. Griddler 2.5 PRO is designed to assess different cell types, and gain a better understanding of the limiting factors that influence solar cell characteristics in laboratory and field settings. The finite-element method (FEM) is applied in solar cell modeling to approximate the cell plane as a network of resistors and diodes. It also features an interface for generating H-patterns and back metal grids. The simulations varied the number of busbars used on the front side metal grids of solar cells from 1 to 5 and the number of metal fingers used for grid pattern optimization from 80 to 130, with finger widths ranging from 10 to 60 µm. For optimization of efficiency and fill factor, various styles (straight, rectangular pad tapered, round pad, digital, two split, and three split) and shapes (straight, pointed, digital, apollo, and wine bottle) were explored. The front and rear contact resistances were kept constant during these simulations to obtain the best fill factor and efficiency. In this model, with 110 fingers (the finger sheet resistance of front and rear sides is kept at 3 mΩ/□) and four busbars, with two split style and straight shapes and a finger width of 25 µm, was designed to achieve maximum performance of the solar cell. Various recombination loss factors in the cells are also analyzed. The results indicate that this is one of the most efficient silicon solar cells modeled, with a fill factor and efficiency of 80 % and 19.55 %, respectively, which is noteworthy for a planar solar cell.

Influence of Temperature on Acid‐Based Wet Chemical Texturization for Ultralow Optical Reflectance (<2%) of mc‐Si Wafer for PV Applications

AbstractThis study proposes a method to enhance the efficiency and optical properties of silicon solar cells made from as‐cut boron‐doped p‐type multicrystalline silicon (mi‐Si) wafers through acid‐based chemical texturization. Achieving lower reflectance is crucial for improving solar cell efficiency, and this can be attained through optimized chemical etching. The research demonstrates achieving a reflectance below 2% on the wafer surface after optimal chemical etching. Wet chemical etching is employed as the surface treatment method, using the same chemical etchant with varying conditions for the texturing process. The study compares temperature‐maintained chemical etching and without temperature maintenance. The chemicals used include HF + HNO3 + CH3COOH at temperatures of 50 °C and room temperature, with etching durations of 2, 5, 10, and 15 minutes, respectively. The as‐cut boron‐doped p‐type mc‐Si wafer grains are analyzed using UV‐vis spectroscopy, optical microscopy, Fourier transform infrared spectroscopy, thickness profilometry, scanning electron microscopy, and X‐ray diffraction spectroscopy, both before and after etching. Among the different conditions tested, the chemical etchant HF + HNO3 + CH3COOH at 50 °C for a 5‐minute etching duration yields favorable results, with reflectivity below 2%. The orientation of mc‐silicon wafer grains is determined using X‐ray diffraction spectroscopy.

Continuously in-situ manufacture of perovskite quantum dots/POE encapsulation adhesive film for silicon solar cell enhancement application

Converting the UV-blue irradiation into longer wavelength can efficiently ameliorate the insufficient solar spectral response and enhance the power conversion efficiency (PCE) of silicon solar cells, whereas there is still no appropriate strategy to make the corresponding luminescence downshifting materials compatible with commercial silicon photovoltaic modules practically. Herein, we first demonstrate an in-situ fabricated CsPbBr3 PQDs/POE encapsulation adhesive film, which can simultaneously achieve continuously large-scale manufacture through melt extrusion and possess well compatibility with the encapsulation technique of silicon photovoltaic modules. According to the separate granulation preparation and technical optimization, the composited adhesive film exhibits an intensive PL emission at 515 nm with a full width at a half-maximum of 20 nm and an ultra high PLQY of 98.2%. Moreover, less than 5% PL intensity decline even after keeping in 50 °C/90 RH aging condition for >2400 h proves its excellent working stability and barrier property. By means of hot pressing operation, the silicon solar cells encapsulated with CsPbBr3 PQDs/POE adhesive film harvest an absolute PCE enhancement of 0.68%. This work provides a way of great potential towards further improving the silicon photovoltaic industry and corresponding optoelectronic applications.

Physical vapor deposition of Yb-doped CsPbCl3 thin films for quantum cutting

Ytterbium-doped CsPbCl${}_{3}$ emerges as the primary contender for a quantum cutting coating on silicon solar cells, aiming to enhance both their efficiencies and durability. This is accomplished by converting each incident ultraviolet and blue photon with energies greater than 2.5 eV into two 1.25 eV near-infrared red photons. The potential of this approach lies in the possibility of surpassing the Quessier limit, thereby augmenting the efficiencies of silicon solar cells. While thin films produced through colloidal synthesis and nanocrystal dispersions have demonstrated photoluminescence quantum yields nearing 200%, there has been a growing interest in employing physical vapor deposition as a large-area scalable method due to sub-band gap absorption exhibited by colloidal films. In the present study, the authors made an intriguing discovery regarding the significant influence of post-deposition annealing environment and protocols on the near-infrared photoluminescence quantum yields in Yb-doped halide perovskite films that demonstrate the downconversion of ultraviolet and blue light through quantum cutting.

Multi-Resonant Mie Resonator Arrays for Broadband Light Trapping in Ultrathin c-Si Solar Cells.

Effective photon management is critical to realize high power conversion efficiencies for thin crystalline silicon (c-Si) solar cells. Standard few-100-µm-thick bulk cells achieve light trapping with macroscopic surface textures covered by thin, continuous antireflection coatings. Such sizeable textures are challenging to implement on ultrathin cells. Here, it is illustrated how nanoscale Mie-resonator-arrays with a bimodal size distribution support multiple resonances that can work in concert to achieve simultaneous antireflection and light-trapping across the broad solar spectrum. The effectiveness of these light-trapping antireflection coatings is experimentally demonstrated on a 2.8µm-thick c-Si solar cell. The measured short-circuit current and corresponding power conversion efficiency are notably improved, achieving efficiencies as high as 11.2%. Measurements of the saturation current density on completed cells indicate that thermal oxides can effectively limit surface recombination. The presented design principles are applicable to a wide range of solar cells.

Enhancing the efficiency and short-circuit current of silicon solar cells using MoO3 as emitter layers

Molybdenum trioxide (MoO3) is an interesting material for optoelectronic applications due to their low-cost, simple processing and thickness-dependent band gap tunability. So far, however, few have been reported to date the impact of post-synthesis annealing on the electrical characteristics of the MoO3 in silicon heterojunctions solar cells. Here, we show that Ar annealing treatment can promote the crystallization of MoO3 nano structures (NSs) and enlarge the MoO3 NSs crystalline size. In this work, thermal evaporation technique is used to prepare MoO3 NSs to be used as emitter layers in silicon heterojunctions solar cell. Then, the as-synthesized sample is annealed under Ar gas flow at 600 °C to improve structural and optical properties of the sample. It is noted that by Ar treatment at 600 °C, we found its quantum efficiency (QE) enhances from 8.41 % to 10.74 %, showing a 27.70 % increase due to a significant enhancement of short circuit-current (ISC). Furthermore, EQE of Ag/Ar treatment MoO3/n-type Si/Ag showed significant enhancement entire spectra range especially in visible region respect to the bare cell.

Excellent surface passivation of p-type TOPCon enabled by ozone-gas oxidation with a single-sided saturation current density of ∼ 4.5 fA/cm2

High-quality p-type tunnel oxide passivated contact (p-type TOPCon) is a feasible technical solution to further improve the efficiency of TOPCon silicon solar cells. Plasma-enhanced chemical vapor deposition (PECVD) technology route could deposit boron-doped amorphous silicon film in-situ and thus becomes one of the most promising industry routes to prepare the TOPCon structure. However, the passivation quality of p-type TOPCon by PECVD is not satisfactory till now. In this work, we develop the high-performance p-type TOPCon technology by integrating the ozone-gas oxidation to prepare the ultra-thin SiOx film, which shows excellent passivation and contact properties. The experimental results suggest that the double-sided p-type TOPCon passivated samples with p-type Si substrates receive a maximal implied open-circuit voltage (iVoc) of ∼ 734 mV together with a minimum single-sided saturation current density (J0,s) of ∼ 4.5 fA/cm2. Correspondingly, the contact resistivity is less than 5 mΩ·cm2, yielding a high selectivity S10 of 15.6, which is one of the best values for p-type TOPCon technology. As a result, the precursor cell manifests an excellent iVoc of 717 mV, and the p-type silicon solar cell with rear-sided p-type TOPCon passivating contact receives a high efficiency of 22.23%. Generally, this work provides a promising technology for preparing the high-quality p-type TOPCon passivating contact for industrial application.

Self‐Assembled Monolayer Ti3C2TxMXene as Electron Selective Heterocontact for Crystalline Silicon Solar Cells

Carrier‐selective contact is an essential strategy to improve the power conversion efficiency (PCE) of crystalline silicon (c‐Si) solar cells by enhancing carrier transport and reducing recombination. Many two‐dimensional transition metal carbides/nitrides (MXene) possess excellent electrical conductivity and tunable work function, enabling them as potential carrier‐selective contact materials for c‐Si solar cells. Herein, low work function (3.71 eV) monolayer Ti3C2Txthin films are fabricated with an ordered arrangement of nanosheets by interfacial self‐assembly method, and the Ti3C2Tx/n‐type c‐Si heterostructure achieves extremely low contact resistivity (22.64 mΩ cm2). Dopant‐free heterojunction crystalline silicon solar cell with self‐assembled monolayer Ti3C2Txelectron‐selective contact is reported for the first time, showing the highest PCE of 16.46% among MXene monolayer‐based c‐Si solar cells, which is mainly attributed to the greatly increased fill factor and open circuit voltage by the accession of self‐assembled monolayer Ti3C2Txas electron transport layer. This work opens up the possibility of applying MXene as electron transport material for photovoltaic devices.

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)