Polysilicon Solar Cells Research Articles

Self-Healable Sandfish Scale-Inspired Scalable Triboelectric Layer for Hybrid Energy Harvesting in Desert Environment.

In deserts, sedimentation from frequent dust activities on solar cells poses a substantial technical challenge, reducing efficiency and necessitating advanced cost-inefficient cleaning mechanisms. Herein, a novel sandfish scale-inspired self-healing fluorinated copolymer-based triboelectric layer is directly incorporated on top of the polysilicon solar cell for sustained hybrid energy harvesting. The transparent biomimetic layer, with distinctive saw-tooth microstructured morphology, exhibits ultra-low sand adhesion and high abrasion-resistant properties, inhibits sedimentation deposition on solar cells, and concurrently harvests kinetic energy from wind-driven sand particles through triboelectric nanogenerator (TENG). The film exhibits a low friction coefficient (0.149), minimal sand adhesion force (27 nN), and a small wear area (327 µm2). In addition, over 2 months, a solar cell with the sandfish scale-inspired structure demonstrates only a 16% decline in maximum power output compared to the bare solar cell, which experiences a 60% decline. Further, the sandfish scale-based TENG device's electrical output is fully restored to its original value after a 6-h self-healing cycle and maintains consistent stable outputs. These results highlight the exceptional advantages of employing biomimetic self-healing materials as robust triboelectric layers, showcasing sustained device stability and durability for prolonged use in harsh desert environments, ultimately contributing to a low cost-of-electricity generation paradigm.

Anchoring Cs+ Ions on Carbon Vacancies for Selective CO2 Electroreduction to CO at High Current Densities in Membrane Electrode Assembly Electrolyzers

AbstractElectrolyte cations have been demonstrated to effectively enhance the rate and selectivity of the electrochemical CO2 reduction reaction (CO2RR), yet their implementation in electrolyte‐free membrane electrode assembly (MEA) electrolyzer presents significant challenges. Herein, an anchored cation strategy that immobilizes Cs+ on carbon vacancies was designed and innovatively implemented in MEA electrolyzer, enabling highly efficient CO2 electroreduction over commercial silver catalyst. Our approach achieves a CO partial current density of approximately 500 mA cm−2 in the MEA electrolyzer, three‐fold enhancement compared to pure Ag. In situ Raman and theoretical analyses, combined with machine learning potentials, reveal anchored Cs induces an electric field that significantly promotes the adsorption of *CO2− intermediates through performing muti‐point energy calculations on each structure. Furthermore, reduced adsorption of *OH intermediates effectively hampers competing hydrogen evolution reaction, as clarified by disk electrode experiments and density functional theory studies. Additionally, coupling our system with commercial polysilicon solar cells yields a notable solar‐to‐CO energy conversion efficiency of 8.3 %. This study opens a new avenue for developing effective cation‐promoting strategy in MEA reactors for efficient CO2RR.

Anchoring Cs+ Ions on Carbon Vacancies for Selective CO2 Electroreduction to CO at High Current Densities in Membrane Electrode Assembly Electrolyzers.

Electrolyte cations have been demonstrated to effectively enhance the rate and selectivity of the electrochemical CO2 reduction reaction (CO2RR), yet their implementation in electrolyte-free membrane electrode assembly (MEA) electrolyzer presents significant challenges. Herein, an anchored cation strategy that immobilizes Cs+ on carbon vacancies was designed and innovatively implemented in MEA electrolyzer, enabling highly efficient CO2 electroreduction over commercial silver catalyst. Our approach achieves a CO partial current density of approximately 500 mA cm-2 in the MEA electrolyzer, three-fold enhancement compared to pure Ag. In situ Raman and theoretical analyses, combined with machine learning potentials, reveal anchored Cs induces an electric field that significantly promotes the adsorption of *CO2 - intermediates through performing muti-point energy calculations on each structure. Furthermore, reduced adsorption of *OH intermediates effectively hampers competing hydrogen evolution reaction, as clarified by disk electrode experiments and density functional theory studies. Additionally, coupling our system with commercial polysilicon solar cells yields a notable solar-to-CO energy conversion efficiency of 8.3 %. This study opens a new avenue for developing effective cation-promoting strategy in MEA reactors for efficient CO2RR.

Tailored nano-pillar structures on surfaces: facile formation and multifunctional properties

Nano-pillar structured surfaces have prized for exceptional optoelectronic properties and biocompatibility but commonly complex, expensive, and inflexible in production. A systematic investigation of the formation, mechanisms, and properties of nanostructures induced by nano-capillaries remains unexplored. Through this study, the facile formation of nano-pillared surfaces induced by designable nano-capillaries on AAO template demonstrated significant improvements in antibacterial effect, spectral structural color and anti-reflection characteristics. Reverse molding of nano-pillar arrays with aspect ratios of up to 1.2 on polydimethylsiloxane (PDMS) films yielded a super-hydrophobic surface of 150° contact angle (CA). Through the utilization of computational fluid mechanics model, a direct correlation was demonstrated between the aspect ratio of nano-pillars and the viscosity of PDMS. The nano-pillared surfaces had remarkable antibacterial rates of 91% for Escherichia coli and 89% for Staphylococcus aureus. In addition, the structured surfaces exhibited color spanning from light blue to light red by tuning nano-pillars dimensions, incident light angle, and/or adding reflective metallic coating, which offered unique visualization effects for anti-counterfeiting. Moreover, the superior light-trapping and anti-reflection of the nano-pillared surface significantly increased the power conversion efficiency (PCE) 19% from the base performance of the polysilicon solar cells.

Phosphorus deactivation mechanisms by hydrogenation in the n+ emitter region and its effect on defects passivation in n+pp+ poly-silicon solar cells

Doping level of the n+ emitter region is an essential parameter that controls the performance of the n+ pp+ poly-silicon solar cells. Also, most poly-silicon n+ pp+ solar cell manufacturers apply hydrogenation from the phosphorus emitter n+ side to improve photovoltaic efficiency. Although hydrogen can passivate defects as well as it changes initial phosphorus doping level through phosphorus-hydrogen complex formation. Consequently, phosphorus deactivation can have a harmful effect on photovoltaic efficiency. In this context, the primary purpose of this work is to investigate the phosphorus deactivation in n+ emitter region and its effect on defects passivation of hydrogenated n+ pp+ poly-silicon solar cells. To do this, hydrogenation is performed by microwave plasma discharge involving an electron cyclotron resonance system. Besides, hydrogen passivates defects in poly-silicon, at the same time it deactivates phosphorus. For this reason, we have chosen to separate these simultaneous effects. So, we performed phosphorus deactivation on Schottky diodes-based mono-silicon, while defect passivation was operated in n+ pp+ poly-silicon solar cells. Our results reveal that hydrogen effectively deactivates phosphorus dopant. This effect is deeper in Schottky diodes with low initial phosphorus doping level where hydrogen diffuses easily in the bulk. This behavior is clearly revealed in open circuit-voltage values (Voc) measured on n+ pp+ samples. In fact, solar cells with low phosphorus concentration in n+ region revealed 319 mV compared to 230 mV for high doping level. Also, all n+ pp+ poly-silicon solar cells show a saturation of Voc at high microwave plasma power. Reasons for such case were explained and discussed in detail.

Tuning of passivation efficiency of defects in emitter region of polysilicon solar cells using hydrogen plasma

Tuning of passivation efficiency of defects in emitter region of polysilicon solar cells using hydrogen plasma

Preparation of Perovskite Solar Cells in the Air: Degradation Mechanism and Prospects on Large‐Area Fabrication†

Comprehensive SummaryThe preparation of perovskite solar cells (PSCs) in the air environment has attracted the attention of numerous experimenters due to its low preparation cost and the possibility of commercialization. Although the power conversion efficiency (PCE) of PSCs has increased rapidly and exceeded 25%, which is comparable to commercial polysilicon solar cells, most certified or reported high‐efficiency perovskite solar cells are still confined to glove boxes or relatively small active areas in the air environment due to moisture, oxygen, high temperature, and ultraviolet (UV) factors. In this review, the factors that lead to perovskite degradation are reviewed, and the appropriate strategies for manufacturing high‐efficiency and stable perovskite solar cells under environmental conditions are summarized to help the technology be commercialized for high‐quality, stable, and large‐area perovskite thin films in the air.

COMPARATIVE STUDY OF THE RECOMBINANT ACTIVITY EFFECT AT THE GRAIN BOUNDARIES IN SILICON SOLAR CELLS

This work studies the effect of carrier trapping and the recombination activity at the grain boundaries in the p-layer of polysilicon solar cells with respect to the deposition temperature. The dependence of the grain size on the deposition temperature was studied in different samples of boron-doped low-pressure chemical vapor deposition (LPCVD) silicon deposits, conducted in a horizontal low-pressure atmospheric pressure reactor where the temperature varied over a range from 520 °C to about 605 °C. The obtained results show clear evidence of dependence on effective changes in the trapping effect as a function of the trapping density states, the doping level and the thickness dimension of the deposited layer.

Smart Solar‐Panel Umbrella toward High‐Efficient Hybrid Solar and Rain Energy Harvesting

Solar photovoltaic power generation technology is the top priority of the global energy development strategy. Although the photoelectric conversion efficiency of crystalline silicon solar cells is as high as 33.7%, the power generation efficiency is relatively low or even unable to generate power normally under low‐light environments such as rainy weather and a cloudy day. Herein, a smart solar panel umbrella system with an auto open and close function is realized by integrating a polysilicon solar cell module and an interdigitated electrode structure triboelectric nanogenerator (IDE–TENG) toward hybrid solar and rain energy harvesting. The output performances of the IDE–TENG are systematically investigated and optimized by regulating the dielectric thickness, inclination angle of IDE–TENG, and various drip types. On this basis, combined with the solar module, the function of auto open and close for the smart solar panel system is realized by a 32‐bit microcontroller and a raindrop sensor, which can be automatically switched as the weather changes and maintain high power conversion efficiency of 19.61% of the solar cell. This smart solar panel umbrella system can be used as a self‐powered supply for all‐weather landscape lighting to save the utilization of fossil energy and contribute in the realization of carbon neutrality.

Hydrometallurgical purification of solar cell silicon scraps through chemical etching with HF-HNO3-H2SO4

The top-cut scraps of silicon ingots are a major source of waste in the production of polysilicon solar cells. In this study, purification of solar cell silicon scraps through chemical etching was carried out. Certain parameters, such as solvent types, etching temperature, ultrasonic power, and ultrasonic frequency were investigated. The optimal conditions were determined to be HF – H2SO4 – HNO3 mixed acid, reaction temperature of 60 °C, ultrasonic frequency of 45 kHz and ultrasonic power of 240 W. Chemical analysis demonstrated that iron was removed. Inclusions were removed under the observation of a microscope. Results indicated that the solar-cell silicon scraps were purified at a low cost.

Modeling the response of an illuminated polysilicon solar cell under the influence of radio waves, a 3D approach

This work investigated the response of an illuminated polysilicon PV cell under AM radio waves. Using a 3 D analysis, the equations which describe the movement of excess electrons and their space and time behavior were solved in order to first find the density of the excess electrons and to subsequently derive the current density and the voltage. The effect of the amplitude of the electromagnetic field (EMF) on the current density and the voltage were studied by varying the distance between the PV cell and an AM radio antenna. The combination of the two characteristics, i.e. current density–voltage and Power–Voltageallowed the computation of the efficiency, the fill factor and the parasitic resistances (Rs, Rsh) of the electrical equivalent circuit of the PV cell. The study showed that from infinite distance to 50 m, corresponding to the Fraunhofer zone, the conversion efficiency increases slightly by about 1% and the fill factor decreases within the same order of magnitude. On the other hand, the series and shunt resistances fall considerably down by about 14% and 13% respectively.The power output curves versus the junction dynamic velocity which allow the computation of the shunt resistance, are used to highlight the impact of the electromagnetic field (EMF) on the operation of the cell. Between an infinite distance and 50 m, the results indicate a very high drop of the shunt resistance (from 64,280 Ω cm 2 to 11 Ω cm 2). Overall, one can conclude that the presence of EMF adversely affects the operation of polysilicon PV cell considering the high drop of the shunt resistance.

Experimental study of solar photovoltaic/thermal (PV/T) air collector drying performance

Solar thermal technology has prospects for the broad application of drying agricultural and associated products. Solar hot air drying technology can effectively solve storage and transportation problems for agricultural and associated products. To improve comprehensive solar energy utilization efficiency, in this study a solar hot-air drying system, based on a comprehensive solar photovoltaic/thermal utilization collector, was designed and built. In this system, amorphous silicon solar cell and polysilicon solar cell modules provide thermal and electrical energy to the system during drying. The drying characteristics of turnips and the thermal and electrical characteristics of the solar photovoltaic/thermal air collector were studied. The results showed that seven direct current fans at the air entrance and 12 internal circulation fans on both sides of the drying chamber turned on the solar drying system compared with seven direct current fans at the air drying chamber entrance that turned on the system, which shortens the turnip drying time by 10 h. The average thermal efficiency, average electrical efficiency, and comprehensive utilization efficiency of the amorphoussilicon photovoltaic/thermal collector are 46.8%, 5.7% and 54.4%, respectively. The average thermal efficiency, average electrical efficiency, and comprehensive utilization efficiency of the polysilicon photovoltaic/thermal collector are 40.7%, 6.8% and 55.4%, respectively.

Hydrogen Diffusion Mechanism in Polysilicon Solar Cells Deduced from Analysis of Dopant Deactivation and Open-Circuit Voltage Evolution

Hydrogen Diffusion Mechanism in Polysilicon Solar Cells Deduced from Analysis of Dopant Deactivation and Open-Circuit Voltage Evolution

2D Modeling of Solar Cell p-n Radial Junction: Study of Photocurrent Density and Quantum Efficiency in Static Mode under Monochromatic Illumination

A theoretical study of a polysilicon solar cell with a radial junction in static regime under monochromatic illumination is presented in this paper. The junction radial solar cell geometry is illustrated and described. The carriers’ diffusion equation is established and solved under quasi-neutral base assumption with boundaries conditions and Bessel equations. New analytical expressions of electrons and holes photocurrent density and quantum efficiency are found. The wavelength and structural parameters (base radius, base thickness and wavelength) influences on photocurrent density and quantum efficiency are carried out and examined.

2D Modeling of Solar Cell Radial Junction: Study of Carriers Charge Density and Photocurrent Density in Static Mode under Monochromatic Illumination

A theoretical study of a polysilicon solar cell with a radial junction in static regime under monochromatic illumination is presented in this paper. The junction radial solar cell geometry is illustrated and described. The carriers’ diffusion equation is established and solved under quasi-neutral base assumption with boundaries conditions and Bessel equations. New analytical expressions of electrons and holes density and photocurrent are found. The wavelength and structural parameters (base radius, emitter thickness) influences on charge carriers density and photocurrent are shown and examined.

Study of the effect of experimental conditions on polysilicon solar cells

The aim of this work is to study the electrical and thermal characteristics of the PV module based on polysilicon solar cells elaborated with LPCVD processing of silicon. We shall proceed by using two structures of cells, taking into account the effect of two specific experimental features which are the thickness of the formed cells and the deposition temperature of the P-layer. The obtained results show a significant influence of both parameters on the performance of the PV module. Specifically, these parameters control the resistivity value in each cell forming the module.

Fabrication of ultra-low antireflection SiNWs arrays from mc-Si using one step MACE

In this work, SiNWs arrays were fabricated from mc-Si wafer using one step nano-silver catalyzed chemical etching method. The effect of AgNO3 concentration on morphology structure, antireflection property and effective carrier lifetime of textured mc-Si were carefully studied. The results indicate that the length and inter spacing of SiNWs arrays are conducive for improving antireflection property of SiNWs arrays, but the increasing etching seriously deteriorates effective carrier lifetime. Moreover, KOH correction of SiNWs was performed to further reduce the reflectance loss, which is also conducive to reduce the photo-generated carrier recombination. Under preference immersion time of 240 s, a large scale SiNWs arrays with the ultra-low antireflection ability of ~3.4% and excellent effective carrier lifetime of 3.30 μs can be obtained, which shows a great significance for producing high-efficiency polysilicon solar cells.

A high efficiency industrial polysilicon solar cell with a honeycomb-like surface fabricated by wet etching using a photoresist mask

In this paper, an effective and low cost method of texturization was introduced into the fabrication process for industrial multicrystalline silicon solar cell production. The purpose of the method was to reduce reflectance by creating a honeycomb-like textured surface using a masked wet etching process. A negative photoresist film was selected as an etching mask. Although large surface roughness of wafer was considered to affect the adhesion and acid resistance of etching mask, a honeycomb-like textured surface with a pitch of 18μm was fabricated successfully. The etched pits had a nearly smooth spherical segment surface, an average aperture of 15.1μm, and a depth of 6.5μm. This regular textured surface had a low light reflectivity of approximately 20.5% and greatly increased the carrier lifetime. Compared with multicrystalline silicon solar cells textured by conventional acid etching, the average short circuit current increased by 2.2% and the average efficiency increased from 17.41% to 17.75%, a net gain of 0.34%. And a high throughput above 2400 pieces per hour was obtained. This texturing technique is expected to promote the application of diamond-wire cut multicrystalline silicon wafers with the low saw-damage in the future.

Structure and antireflection properties of SiNWs arrays form mc-Si wafer through Ag-catalyzed chemical etching

A simple and low cost MACE method was demonstrated for efficiently texturing commercial mc-Si wafer at room temperature. The effects of fabrication parameters (deposition time, HF concentration, H2O2 concentration, and etching time) on the morphology structure, antireflection property of textured mc-Si were carefully studied. The large scale SiNWs arrays with different structure can be obtained under various fabrication conditions. Meanwhile, the results indicate that the fabricate parameters have important effect on the reflectance of textured mc-Si sample in the order of etching time>deposition time>H2O2 concentration>HF concentration. The comprehensive research results indicate that it is more beneficial for the nanowire arrays with tapering structure and the length of 13μm to obtain excellent antireflection property. Under these optimization conditions, the textured mc-Si shows an outstanding anti-reflectance ability of ∼5.6%, which indicates that the Ag-catalysis etched mc-Si shows a huge potential application in high-efficiency polysilicon solar cells.

Internal quantum efficiency improvement in polysilicon solar cells with porous silicon layer on the rear side

The present paper reports on a simulation study carried out to determine and optimize the effect of porous silicon (PS) layer at the rear side on the performance of thin polysilicon solar cells. It analytically solved the complete set of equations necessary to determine the contribution that this material has with regard to the internal quantum efficiency (IQE) of the cell when acting as a backside reflector. The contribution of the different regions of the cell, the increase in IQE, and the effects of high porosity and number of PS layers were derived and compared to conventional BSF solar cells. The findings revealed that the IQE of the solar cell with a PS layer at the backside was higher than that of conventional BSF, particularly in terms of medium and long wavelength range λ > 0.5 μm. This improvement was more significant with thin cells, large grain widths, and well-passivated grain boundaries. Furthermore, while the use of the PS layer had a significant effect on the contribution of the base, it exerted no effect on the contribution of the emitter and depletion regions. Overall, the maximum level of IQE improvement was recorded with three double-porosity structures in the PS layer, reaching a high porosity value of about 80 %.