Silicon Solar Cell Applications Research Articles

A novel multifunctional naphthalene triazole columnar liquid crystal: synthesis, self-assembly and application in silicon solar cells

Herein, click reaction was used as a crucial step to effectively synthesize a new multifunctional naphthalene triazole columnar liquid crystal ICm/n. The properties of liquid crystal and gel in ICm/n were investigated using POM, DSC, XRD and SEM. ICm/n can self-assemble into square columnar liquid crystals in their pure state and form organogels in N,N-dimethylformamide (DMF). In addition, ICm/n can be used as a Fe3+ chemosensor. Interestingly, the addition of lithium salts has a significant impact on the self-assembly, molecular dynamics and ionic conductivity of the compounds, thus potentially providing nanostructured LC electrolytes with continuous substrate ionic conductivity. Additionally, the use of ICm/n as a dopant in the poly (3,4-ethylenedioxythiophene): polystyrene (PEDOT: PSS) hole injection layer greatly enhanced the photoelectric conversion efficiency (PCE) of Si/PEDOT: PSS heterojunction solar cells, boosting it from 2.08 % to 8.10 %. The current work offers a novel method for creating liquid crystal (LC) materials with several uses for naphthalene triazoles.

Investigation on TiO2 spin-coated thin films effect on the optoelectronic properties of stain-etched porous silicon for solar cell applications

This article aims to improve the opto-electronic properties of porous silicon (PS) to integrate it as an anti-reflecting coating in solar cell applications. The enhancement of its properties is achieved through the passivation of its surface by titanium dioxide (TiO2). Samples of porous silicon were elaborated using stain etching technique, then treated with the metal oxide using spin-coating technique. The film thickness was varied to study the thickness effect on the properties of the TiO2/PS structure. Morphological study has shown that most pores were covered with TiO2 structures, resulting in an overall change in the surface morphology. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis has confirmed the TiO2 deposition on PS surface. The passivation of PS with TiO2 had more interesting results, especially in the case of PS passivated with three layers of TiO2, which suggests a good coverage of the surface of PS, results confirmed by optical study and minority carrier lifetime measurement. Moreover, a simulation was also carried out using PC1D. The optoelectronic results of the synthesized TiO2/PS samples were applied on a built-in model of a commercialized silicon-based solar cell. The efficiency increased from 11% for an untreated silicon solar to 15.8% for the cell modeled with 3 layers of TiO2 deposited on PS.

Growth rate of AL2O3 Thin Film by Liquid Phase Deposition as an Anti-reflection Coating Layer on Crystalline Silicon for Solar Cell Applications

The fabrication of photovoltaic (PV) device requires that surface reflectance of solar cells has to be minimized to achieve higher photo-conversion efficiency (PCE). Antireflection coating layer is deposited on the surface of a p-type crystalline silicon material to reduce the surface reflections of solar radiation and increase its absorption for efficient solar cell application. In this work, aluminum oxide thin film by liquid phase deposition (LPD-Al2O­3) is synthesized from combined solution of aluminum sulfate octadecahydrate (Al2(SO4)3·18H2­O) and sodium carbonate (NaHCO3) with pH of 3.1. Some samples of p-type (100) crystalline silicon (c-Si) wafers of resistivity 1 – 10 mΩ were immersed inside the growth liquid of LPD-Al2O­3 thin film for 1hr – 2.5 hours. This is followed by annealing the samples at a temperature of 450oC, the deposition rate is faster in the range 1 – 1.5 hours is about 35nm/hr. As the growth time increases, the growth rate of the film decreases and remains nearly constant at about 10 nm/hour at 1 – 2 hours. When the growth time exceeds 2 hours, the film thickness remains unchanged showing that the liquid has lost in growth ability. The weighted average reflection (%) of planar c-Si is reduced from 44.9 % to 29.6 % after deposition of the LPD-Al2O­3 for 2.5 hours growth time, indicating a 34.1 % reduction in reflection within wavelength region of 300–1100 nm. While the root means square (RMS) surface roughness of 36.5 nm was also recorded at the highest growth time of 2.5 hours. This shows the effect of thicker LPD-Al2O­3 thin film layer increases the anti-reflecting coating property of the material.

Growth rate of AL2O3 Thin Film by Liquid Phase Deposition as an Anti-reflection Coating Layer on Crystalline Silicon for Solar Cell Applications

The fabrication of photovoltaic (PV) device requires that surface reflectance of solar cells has to be minimized to achieve higher photo-conversion efficiency (PCE). Antireflection coating layer is deposited on the surface of a p-type crystalline silicon material to reduce the surface reflections of solar radiation and increase its absorption for efficient solar cell application. In this work, aluminum oxide thin film by liquid phase deposition (LPD-Al2O­3) is synthesized from combined solution of aluminum sulfate octadecahydrate (Al2(SO4)3·18H2­O) and sodium carbonate (NaHCO3) with pH of 3.1. Some samples of p-type (100) crystalline silicon (c-Si) wafers of resistivity 1 – 10 mΩ were immersed inside the growth liquid of LPD-Al2O­3 thin film for 1hr – 2.5 hours. This is followed by annealing the samples at a temperature of 450oC, the deposition rate is faster in the range 1 – 1.5 hours is about 35nm/hr. As the growth time increases, the growth rate of the film decreases and remains nearly constant at about 10 nm/hour at 1 – 2 hours. When the growth time exceeds 2 hours, the film thickness remains unchanged showing that the liquid has lost in growth ability. The weighted average reflection (%) of planar c-Si is reduced from 44.9 % to 29.6 % after deposition of the LPD-Al2O­3 for 2.5 hours growth time, indicating a 34.1 % reduction in reflection within wavelength region of 300–1100 nm. While the root means square (RMS) surface roughness of 36.5 nm was also recorded at the highest growth time of 2.5 hours. This shows the effect of thicker LPD-Al2O­3 thin film layer increases the anti-reflecting coating property of the material.

Broadband Sensitized Near‐Infrared Quantum Cutting Materials for Silicon Solar Cells: Progress, Challenges, and Perspectives

Silicon solar cells are currently the most widely used type, accounting for more than 90% of the commercial market. However, the spectral mismatch between the solar spectrum and the absorption spectra of the cells is the main cause restricting their conversion efficiency, which cannot exceed the Shockley–Queisser limit. Quantum cutting can convert one high‐energy photon into two or more low‐energy photons and reduce the energy loss of the high‐energy photons, providing a way to improve the photoelectric conversion efficiency (PCE) of silicon solar cells. The unique electronic configuration of rare‐earth elements gives them excellent optical properties and makes them good candidates for the luminescent centers of quantum cutting materials. This article reviews their luminescence mechanism, energy transfer (ET) mechanism, and application in silicon solar cells and outlines the potential problems of broadband‐sensitized near‐infrared (NIR) quantum cutting materials. Some key issues and future directions are also discussed.

Modelling and analysis of high efficiency silicon solar cell using double layers anti-reflection coatings (ARC)

The modernization that is currently taking over across the world is resulting in numerous advancements in a variety of industries, and the most notable and apparent development is the rising use of solar energy, which has become more prevalent every day. Most companies, residences, schools, and other organizations rely mostly on solar energy as the main source of electricity. It was discovered that anti-reflective coating (ARC) had been applied to solar cells with the goal of increasing power conversion efficiency, decreasing reflection loss, and improving absorption. Although a single layer of ARC is sufficient, applying an additional layer might improve the solar cell application’s effectiveness. Hence, the modeling and analysis of double layers of anti-reflection coating (ARC) with different types of materials have been investigated and evaluated using personal computer one-dimensional (PC1D) simulation software. In this study, the double-layer anti-reflection coating on the solar cell was modeled using PC1D, where this software allowed for one-dimensional simulation of the parameters required for the operation of semiconductor-based solar energy systems. The PC1D simulation reveals that SiO2/TiO2 has the highest efficiency (22.82%) and lowest reflection compared to Si3N4/TiO2 and ZnO/TiO2. Also, SiO2/TiO2 generates the highest external quantum efficiency (EQE) among ARC double layers, making it ideal for silicon solar cell applications in order to boost the solar cell’s efficiency. The results for the effects of current, voltage, reflection, and EQE of the different double layers of ARC have also been studied in this paper.

Novel Interlayer Boosting the Performance of Evaporated Cu2O Hole‐Selective Contacts in Si Solar Cells

Passivating contacts based on transition metal oxides are of great interest for applications in crystalline silicon (c‐Si) solar cells due to their improved optical transparency and potential cost reduction. In this work, the contact resistivity and passivation for thermally evaporated Cu2O are investigated and optimized, with and without an Al2O3 interlayer, as a hole‐selective contact to c‐Si. Additionally, we implement an Al y TiO x /TiO2 stack as a novel passivating tunnel interlayer for hole‐selective contacts, achieving an implied open‐circuit voltage iV oc of 630 mV and a record‐low J 0 of 212 fA cm−2 while maintaining a contact resistivity ρ c of 62 mΩ cm2. A record‐low ρ c of 8 mΩ cm2 for Cu2O‐based contacts is also demonstrated at the expense of passivation. The addition of the interlayer resulted in a 2% absolute improvement in the efficiency of proof‐of‐concept c‐Si cells with full‐area rear Cu2O contacts, reaching 19.1%.The demonstration of this novel interlayer stack provides new avenues to improve the performance also of other hole‐selective passivating contacts.

The Effects of Porous Silicon and Silicon Nitride Treatments on the Electronic Qualities of Multicrystalline Silicon for Solar Cell Applications

The Effects of Porous Silicon and Silicon Nitride Treatments on the Electronic Qualities of Multicrystalline Silicon for Solar Cell Applications

Investigation of the role of Saw damage in Silver catalyzed Metal Assisted Chemical Etching on Multicrystalline Silicon for Solar cell Application

Investigation of the role of Saw damage in Silver catalyzed Metal Assisted Chemical Etching on Multicrystalline Silicon for Solar cell Application

Detailed investigation of electrical and optical properties of textured n-type and roughened p-type tunnel oxide passivated contacts for screen-printed double-side passivated contact silicon solar cell application

This paper presents detailed characterization and analyses of the optical, electrical, and contact properties of a 35 nm phosphorus-doped (n-type) polysilicon (poly-Si) and a 250 nm boron-doped (p-type) poly-Si deposited respectively on textured and roughed surface. These layers could be applied respectively to the front and rear sides of an n-type Si to produce back junction bifacial screen-printed double-side tunnel oxide passivated contacts (DS-TOPCon) solar cells. Optical and device modeling revealed a short circuit current density loss of 1.5 mA/cm2 and 0.5 mA/cm2 due to absorption in the front n-TOPCon and rear side p-TOPCon layers, respectively. The passivation and contact properties including metalized and unmetallized recombination current density (J0), as well as contact resistivity, were determined as a function of contact firing temperature in the range of 700∼800℃. The passivation quality of the front thin n-TOPCon was found to deteriorate with increased firing temperature while the rear thick p-TOPCon improved. The study showed that the simulated contact firing at 730℃ resulted in the best unmetallized double-side TOPCon precursor, with an excellent implied open-circuit voltage of 730 mV and implied fill factor of ∼86 %. However, the metalized J0 increased and contact resistivity decreased monotonically with the increase in the firing temperature. The 2D device simulations revealed that these layers can produce screen-printed DS-TOPCon cells with an efficiency of ∼22.5 %. Solar cell modeling also showed that the DS-TOPCon solar cell efficiency can reach 24.1 % by decreasing the n-TOPCon thickness to 20 nm and lowering the full area metalized J0 to ∼100 mA/cm2.

One step coating anti-reflective SiO2 film for silicon solar cells applications by atmospheric pressure plasma jet

By utilizing an atmospheric pressure plasma jet, a one-step deposition of anti-reflective silicon dioxide coating was successfully achieved on solar cover glass. A two-dimensional moving platform was utilized to coat large-area cover glass measuring 300 mm * 300 mm. Remarkably, at an input power of 40 W, the temperature of the cover glass remained as low as 59.4 °C. The impact of different motion patterns on the anti-reflective properties of the film was thoroughly investigated. Upon assembling the solar cells, a notable efficiency enhancement from 24.03% to 24.28% was observed. This method demonstrates promising prospects for repairing anti-reflective films on malfunctioning solar cell modules in photovoltaic power plants.

Charge trapping and photovoltaic characteristics in monocrystalline silicon solar cells employing molybdenum oxide and copper oxide stacked hole-selective contacts

A hole-selective contact (HSC) composed of stacked layers of molybdenum oxide (MoOx) and copper oxide (CuOx), called MOCOSL, has been proposed as passivation booster for screen-printed monocrystalline silicon solar cell (SMSC) applications. The passivation quality of MOCOSL is investigated by characterizing its charge trapping properties, including fixed oxide charge (Qf) and interface trap density (Dit). The conversion efficiency (CE) of SMSCs is improved by MOCOSL, resulting in an increase from 20.66% to 21.76%. This improvement is attributed to an increase in the negative Qf and a decrease in Dit, which result in an increase in the open circuit voltage (Voc) and short circuit current (Jsc). Specifically, the number of negative Qf is increased by MOCOSL, which helps to reduce the recombination of charge carriers.

Review of Laser Doping and its Applications in Silicon Solar Cells

Laser-doped selective emitter diffusion techniques have become mainstream in solar cell manufacture covering 60% of the market share in 2022 and are expected to continue to grow to above 90% within the next five years (ITRPV). This was a very rapid uptake of technology, coming from only ∼10% penetration in 2018, and has enabled over 20 fA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> front recombination current reductions on the dominant passivated emitter and rear cell concepts in the same short period. In this article, a broad overview of key concepts in relation to laser doping methods relevant to solar cell manufacturing is given. We first discuss the basic mechanisms behind laser doping along with the benefits over conventional doping methods. The main laser doping approaches reported in the literature are then discussed, along with implications for metallization strategy, particularly in relation to selective emitter and back surface field formation in the dominant passivated emitter and rear cell technology. Different cell concepts that have benefited from the application of laser doping are also discussed. In the last section, we discuss the main defects induced by laser processing of silicon which affect the finished devices, potential and debated causes, as well as some commonly applied treatments for their mitigation.

Development of Phosphorus-Doped Nanoscale Poly-Si Passivating Contacts via Inkjet Printing for Application in Silicon Solar Cells

Herein, high-quality localized phosphorus-doped polycrystalline silicon (poly-Si) passivating contacts containing nanoscale poly-Si film (∼100 nm) on an ultrathin SiOx layer (∼1.5 nm) were fabricated via an inkjet printing technique. A detailed study of the impacts of inkjet printer settings, dopant concentration, and annealing temperature on the poly-Si passivating contact performance (represented by implied open-circuit voltage iVoc and contact resistivity ρc) was carried out. By applying optimized process conditions on symmetrical industrially processed intrinsic poly-Si/SiOx/n-type crystalline Si (c-Si) substrates, good surface passivation was achieved with an iVoc of 699 mV, together with a low ρc of 6.4 mΩ·cm2, after annealing at 975 °C. After a hydrogenation treatment via the deposition of aluminum oxide (AlOx)/silicon nitride (SiNy) stack and subsequent forming gas annealing (FGA), the optimum annealing temperature shifted to 950 °C and the iVoc was further improved to an excellent value of 729 mV. Optical images reveal that a line width of 75 μm can be realized on a mechanically polished silicon wafer. Moreover, high-resolution micro-photoluminescence (μ-PL) maps clearly demonstrate the localization of the doped regions on the symmetrical substrate after annealing. These results show that inkjet printing is a promising technique for the fabrication of localized poly-Si/SiOx passivating contacts in high-efficiency solar cells with high flexibility and simplicity.

Photovoltaic and interface characteristics of mono-crystalline silicon solar cells with molybdenum oxide hole-selective layers by ammonium hydroxide reconstructed nanostructure

Ammonium hydroxide reconstructed nanostructure (AHRN) is proposed as an attachment enhancer between molybdenum oxide (MoOx) hole-selective layers (HSLs) and silicon interface for screen-printed mono-crystalline silicon solar cell (SMSC) applications. The conversion efficiency (CE) is demonstrated from 20.6% to 21.6% for SMSCs with MoO2 HSL and attachment enhancer. The betterment mechanism is attributed to a suitable nanostructure, resulting in the increase of the fill factor and peeling force. Moreover, the interface trap density (Dit) is hardly degraded by MoO2 formed on the Si surface at a specific AHRN.

Green upconversion improvement of TiO2 codoped Er3+-Yb3+ nanoparticles based thin film by adding ALD-Al2O3 for silicon solar cell applications

This paper investigates the upconversion luminescence modification of codoped nanoparticles with lanthanides ions based thin films through adding a coating. First, these nanoparticles based thin films composed of Er3+-Yb3+ co-doped anatase-TiO2 are prepared using spin coating technique supported by a design of experiment (DOE) approach with the Hadamard matrix of order 4 to improve the deposition conditions. For the coating step, different thicknesses of Al2O3 layer are realised by thermal atomic layer deposition (T-ALD) onto the surface of Er3+-Yb3+ co-doped anatase-TiO2 nanoparticles based thin films. The results show that the ALD-Al2O3 coating can benefit the luminescence properties of the upconversion nanoparticles based thin films. Thin ALD-Al2O3 (10 nm) coated stack exhibits similar upconversion luminescence as the uncoated nanoparticles based film but insures also their stability. Meanwhile, for 100 nm ALD-Al2O3 coating, enhancement of the upconversion green emission by 98% at the expense of the red emission compared to uncoated sample is observed. This results are promising to be applied in photovoltaics field.

Performance Enhancement of Crystal Silicon Solar Cell by a CsPbBr3–Cs4PbBr6 Perovskite Quantum Dot @ZnO/Ethylene Vinyl Acetate Copolymer Downshifting Composite Film

Crystal silicon solar cells being the most successful photovoltaic devices have prevailed in the energy market for decades. To further improve the device performance, photon management is necessary. Herein, a CsPbBr3–Cs4PbBr6 perovskite quantum dot@ZnO/ethylene vinyl acetate copolymer downshifting composite film is coated on the silicon solar cell. This downshifting composite film helps to convert high‐energy (UV‐blue) photons to relatively low‐energy photons with a wavelength at about 500 nm, which possess higher sensitivity in silicon solar cells. The effects of tetra‐n‐heptylammonium bromide and Zn(C2H5)2 on composition, optical and luminescence properties of perovskite quantum dots are thoroughly investigated, and a clean quantum dot solution with strong luminescent intensity can be obtained. The perovskite quantum dot@ZnO/ethylene vinyl acetate composite film absolutely improves the efficiency of silicon solar cells by 1.18%. The value is much higher than pure ethylene vinyl acetate (0.42%) and composite film without ZnO (0.57%). Moreover, ZnO inclusion can inhibit Cs and Pb leakage and maintain the device working stability, which is helpful for their commercial application in the future. This study further reveals that the enhancement lies in carrier relaxation energy loss reduction. Herein, a low‐cost downshifting composite film with excellent environmental stability for silicon solar cells applications is proposed.

Comparison of C-, N-, and O-Incorporated Non-blistering PECVD Si Films for Application in SiOx-Based Passivating Contacts for Si Solar Cells

For application in high-efficiency silicon solar cells bearing SiOx-based passivating contacts, we have developed 100 nm thick, PECVD Si-rich amorphous films, capable of being processed in industrial furnaces without blistering, by incorporating adequate amounts of each of C, N, and O in the films during PECVD. We found that non-blistering of the films is a result of the low intrinsic stress (compressive) in the films and not due to a low H content, which, in fact, is much higher in the non-blistering films than in the C-, N-, and O-free films. Among the three types of non-blistering Si-rich amorphous films, we conclude that the O-incorporated one is the most suitable for application in SiOx-based passivating contacts owing to the film’s high excess Si content and ability to crystallize.

Luminescence properties and energy transfer of the near-infrared phosphor Ca3In2Ge3O12:Cr3+,Nd3.

The double doping strategy based on energy transfer is an effective way to regulate the NIR spectral distribution. In this work, Ca3In2Ge3O12:xNd3+ (CIG:xNd3+) and Ca3-x In1.93Ge3O12:0.07Cr3+,yNd3+ (CIG:0.07Cr3+,yNd3+) phosphors are successfully prepared via a high-temperature solid-state method. CIG:0.07Cr3+ shows broadband emission centered at 804 nm, which covers most of the excitation peaks of Nd3+ ions. Under excitation at 480 nm, Cr3+ can provide effective energy transfer to Nd3+. In addition, CIG:0.07Cr3+,0.15Nd3+ has good temperature stability, and maintains 68.98% of the room-temperature intensity at 150 °C. The phosphors can convert short-wave photons to long-wave photons and enhance solar cell utilization, demonstrating the potential application of this material in solar spectral conversion technology.

A new direct band gap Si-Ge allotrope with advanced electronic and optical properties.

Direct-band silicon materials have been a sought-after material for potential applications in silicon photonics and solar cells. Accordingly, methodologies like nanostructure engineering, alloy engineering and strain engineering have been developed. In this work, the particle swarm optimization (PSO) algorithm is used to design direct-band Si-Ge alloys. The findings of phonon computations demonstrate that all these structures are dynamically stable. In addition, ab initio molecular dynamics and elastic constant calculations are carried out, with results indicating these structures are thermodynamically stable at 300 K, as well as being mechanically stable. All of these materials exhibit semiconductor behavior with band gaps of 1.03, 0.68 and 1.37 eV for α, β and γ phases, respectively, at the HSE06 level. The results of effective mass and mobility of carriers that are important in applications show that holes are more easily transported in all structures, with higher concentration of holes accompanied by lower carrier mobility. Different concentrations of holes nh lead to different limits in the scattering process. When nh is lower than the value of around 1016 cm-3, deformation potential scattering is dominant, while the ionized impurity scattering process limits overall mobility when nh is higher than such a value. Finally, the absorption spectra shows that both α and β phases have isotropic optical properties in the X- and Y-directions while strong anisotropy can be seen in the Z-direction. However, the γ phase exhibits no notable isotropy. This investigation finds three direct-band and potentially CMOS compatible materials, a finding which will benefit the development of high efficiency emitters or solar cells.