Crystalline Silicon Research Articles

DFT/TDDFT Investigation of the Effect of Electron Acceptor Groups on Photovoltaic Performance Using Phenothiazine‐Based D‐Ai‐π‐A Dyes for DSSC Applications

AbstractThis review focuses mostly on organic dye‐sensitized solar cells, as they are an attractive, environmentally friendly alternative to traditional silicon solar cells for the production of renewable energy at a lower cost. The dye chromophore is recognized as the central component of the DSSC device. To improve the electrochemical, photovoltaic, and absorption properties of organic sensitizing dyes, we have designed a series of eight new dyes Pi (i = 1.8) based on the DPA‐2 architecture (the reference molecule). We have investigated the effects of internal absorption of different acceptor groups in D‐Ai‐π‐A before and after binding to the TiO2 cluster surface on the ability to inject electrons into the surface. The benzophenothiazine is the D donor, the π‐spacer is furan, and the A acceptor is cycnoacrylic acid. We are using time‐dependent density functional theory (TD‐DFT), and density functional theory (DFT) in our quantum calculations. It is theoretically possible to predict suitable candidates for the DSSC device and identify correlations between their structure and properties by using DFT and TD‐DFT simulations to thoroughly study in detail electronic structures, natural binding orbital (NBO), analysis of UV‐visible absorption spectra, parameters influencing short‐circuit current density (JSC), open‐circuit voltage (VOC), and intramolecular charge transfer (ICT). Additionally, the relationship between optoelectronic properties and molecular structure was investigated, and the effect of auxiliary acceptor groups (Ai) on the primary photovoltaic properties of the reference molecule DPA‐2. The results show that by changing the internal acceptor to DPA‐2 could create a more coplanar and rigid structure. This would cause the energy gap (Eg) for each of the dyes created to significantly shrink, reducing it from 2.29 to 1.38 eV. The absorption spectra's λmax for each dye would also change color, this was because the acceptor moiety Ai of the phenothiazine moiety changed when it came to DPA‐2 (not including compounds P1 and P4). In contrast, P6 and P7 dyes demonstrate an absorption range beyond 500 nm, implying a more efficient utilization of sunlight in the visible spectrum compared to other dyes. Furthermore, all organic dyes show a robust LHE performance (0.919 to 0.993), correlating with the lowest ΔGreg values (0.097 to 0.356) and the most negative ΔGinject values (−2.067 to −1.121). The power conversion efficiency of PCE and JSC could increase according to these results. Therefore, theoretical research into adding a second internal acceptor group to the D‐Ai‐π‐A structure should produce new methods for improving solar energy output.

Improvement of Laser Contact Opening in Bifacial PERC Solar Cells by Optimizing the Dashed Pattern

Improvement of Laser Contact Opening in Bifacial PERC Solar Cells by Optimizing the Dashed Pattern

Low-cost deposition of tunable band gap Zn(O,S) as electron transport layer for crystalline silicon heterojunction solar cells

In recent years, the research on silicon heterojunction (HJT) solar cells based on dopant-free contacts has experienced rapid development. Zn(O,S) is a low work function n-type semiconductor compound with tunable band gap that can be used as the electron transport layer (ETL) in HJT solar cells. In our work, we choose Zn(O,S) as ETL and deposit it via the low-cost chemical bath deposition (CBD) method. Uniform and fast growth of Zn(O,S) films can be obtained by regulating the concentration of the complexing agent and the ratio of reactants to reduce the generation of impurities. To further achieve band matching with c-Si, the Zn(O,S) films are processed with air-annealing to modify the elemental ratios. The air-annealing lowers the interfacial electron transport barrier, which promotes charge separation and transport, thus reducing carrier recombination at the interface. Finally, the PCE of HJT solar cell based on CBD-Zn(O,S) ETL is close to 15 %, providing a new potential route for the development of low-cost HJT solar cells.

Carboxylic Acid Assisted Synthesis of Crystalline Silicon Derived from Coal Fly-Ash for Li-Ion Batteries Anode Material

Carboxylic Acid Assisted Synthesis of Crystalline Silicon Derived from Coal Fly-Ash for Li-Ion Batteries Anode Material

Optimization of rear surface morphology in n-type TOPCon c-Si solar cells

Tunnel oxide passivated contact (TOPCon) crystalline silicon (c-Si) solar cells have attracted much attention because of their superior electrical properties such as the lower contact resistivity and better interface passivation at high temperatures. However, the TOPCon c-Si solar cells also have room for further improvement in optical performance, and the embodiment of optical advantages needs to be matched synchronously in electrical aspect. Here, the rear silicon pyramids with different angles have been achieved through solution corrosion to maximize the light absorption in the c-Si substrate. The light absorption for the pyramid angle of less than 30° is better. Compared with the cell samples with rear pyramid for a certain angle, the samples with flat back surface possess better surface passivation, and the contact resistivity can be reduced effectively by increasing the phosphorus doping concentration and adjusting the annealing temperature. Furthermore, the TOPCon c-Si solar cells with flat rear surface covered by 70 nm poly-Si have been demonstrated to increase the conversion efficiency by about 0.15 % vs. the counterpart for poly-Si of 130 nm thickness, and the improvement is mainly due to the increase of JSC and FF by 0.07 mA/cm2 and 0.72 %, respectively.

Design of 600 WP Solar Power Plant for Juice Vendors Through Off-Grid System

Solar power plants (PLTS) generate electricity from the energy of solar photons. Solar cells, or solar cells made of crystalline silicon, are examples of solar panels that generate electricity through the photovoltaic effect. Thus, the construction of solar power plants (PLTS) is one of the right choices to save energy. The purpose of this study is to utilize the energy that is owned and to introduce it to the surrounding community. The community has widely used solar power generation (PLTS) technology, one of the main components of solar power plants is solar photovoltaic technology, which is used to operate juice blenders, cup sealers, and energy-efficient lighting. PLTS functions as an alternative energy source to help juice traders. Based on solar energy for this off-grid system, it has a power capacity of 3 x 200 WP. This monocrystalline solar panel also has a 300 Ah VRLA battery, a 2000 W inverter, and a 50 A solar charger controller (SCC). In addition, the PLTS off-grid system for juice traders has blender equipment, cup sealers, and lighting with an average power rating of 600 Watts. With an efficiency calculation of 80%, this system can be fully used to support business operations. This study is to develop and Design a 600-watt peak Solar Power Plant using an off-grid system for juice vendors that costs Rp. 22,000,000, including all essential components and services needed to ensure that the system can operate properly

Doping dependence of boron–hydrogen dynamics in crystalline silicon

In this contribution, we investigate the formation and dissociation of boron–hydrogen (BH) pairs in crystalline silicon under thermal equilibrium conditions. Our samples span doping concentrations of nearly two orders of magnitude and are passivated with a layer stack consisting of thin aluminum oxide and hydrogen-rich silicon nitride (Al2O3/SiNx:H). This layer stack acts as a hydrogen source during a following rapid thermal annealing. We characterize the samples using low-temperature Fourier-transform infrared spectroscopy and four-point-probe resistivity measurements. Our findings show that the proportion of hydrogen atoms initially bound to boron (BH pairs) rises with increasing boron concentration. Upon isothermal dark annealing at (163 ± 2) °C, hydrogen present in molecular form, H2, dissociates at a rate directly proportional to the concentration of boron atoms, ∝ [B−], leading to the formation of BH pairs. With prolonged annealing, an unknown hydrogen complex is formed at a rate that is inversely proportional to the square of the boron concentration, ∝ 1/[B−]2, resulting in the disappearance of BH pairs. Based on experimental observations, we derive a kinetic model in which we describe the formation of the unknown complex through neutral hydrogen H0 binding to a sink. Additionally, we investigate the temperature dependence of the reaction rates and find that the H2 dissociation process has an activation energy of (1.11 ± 0.05) eV, which is in close agreement with theoretical predictions.

Optimizing dye-sensitized solar cell efficiency through TiO2/CuS doping: effects of internal parameter variations

Dye-sensitized solar cells (DSSC) have attracted significant research interest due to their semi-transparency, ease of fabrication, cost-effectiveness, and environmental friendliness. This research focuses on enhancing dye-sensitized solar cells efficiency by doping titanium dioxide with copper sulfide and varying internal parameters such as concentration, thickness, and temperature. The primary issue addressed is the low electron mobility of titanium dioxide, which limits its performance as a photoanode. Using simulation methods, this study analyzed dye-sensitized solar cells performance under different doping conditions. The results showed that the highest efficiency of 8.18 % was achieved at a TiO2/CuS concentration of 0.3 %. The optimal photoanode thickness was approximately 3 μm, yielding an efficiency of 8.33 %. Temperature variations at room temperature (275 K, 300 K, and 325 K) resulted in efficiency values of 13.94 %, 15.06 %, and 16.18 %, respectively. These findings indicate that targeted doping and precise control of internal parameters can significantly enhance the performance of titanium dioxide-based dye-sensitized solar cells. The improved efficiency is attributed to enhanced electron mobility and better structural and morphological characteristics of the doped titanium dioxide photoanode. This research provides valuable insights into developing more efficient and sustainable dye-sensitized solar cells. The practical implications of these results are significant for advancing dye-sensitized solar cells as a viable alternative to conventional solar cells, contributing to the global effort to address the energy crisis by providing a cost-effective and environmentally friendly energy source.

Performance prediction of ventilated building-integrated photovoltaic system with lightweight flexible crystalline silicon module based on experimental fitting method

The novel ventilated building-integrated photovoltaic system with lightweight flexible crystalline silicon modules (VL-BIPV) has a self-weight of only about 6 kg/m2, which helps to address weight-bearing challenges on low-capacity industrial building rooftops. However, the unique thermal dissipation features of the system pose challenges for the analysis of its photovoltaic performance and thermal processes. Therefore, a comparative experimental testing approach was employed, comparing the VL-BIPV system with a conventional rooftop photovoltaic system. Using the efficiency equations of the conventional photovoltaic system as a reference, the functional equations were fitted based on experimental results. Based on typical meteorological year data in Nanjing, annual power generation and PV cell temperature variations were evaluated, along with power generation and carbon reduction benefits over a 25-year lifetime. The results indicate that the VL-BIPV system achieves an annual power generation of 262.22 kWh/m2, a 6.52% increase compared to the conventional system. Additionally, the highest average and maximum cell temperatures in the VL-BIPV system during the year are 58.39 °C and 64.74 °C, respectively, both lower than the conventional system's peak at 68.34 °C. Over a 25-year lifespan, the VL-BIPV system reduces carbon emissions by 20.17 kgCO2/Wp, exceeding the conventional system's reduction by 1.25 kgCO2/Wp.

Calculation of the Second EXAFS Cumulant of Si Using the Anharmonic Correlated Einstein Model

The second expanded X-ray absorption fine structure (EXAFS) cumulant of the crystalline silicon (Si) has been studied in the temperature-dependent. This is calculated in explicit forms using the anharmonic correlated Einstein (ACE) model developed from the correlated Einstein model based on the anharmonic effective potential and the quantum statistical theory. The numerical results of Si in the temperature range from 0 to 1200 K are in good agreement with those obtained by the other theoretical models and experiments at several temperatures. The analytical results show that the ACE model is suitable for analyzing the experimental EXAFS data of diamond cubics.

Hydrogenation by catalytically generated atomic hydrogen for passivating contacts in crystalline silicon solar cells

Hydrogenation employing catalytically generated atomic hydrogen (Cat-H) is implemented on stacks of n-type polycrystalline silicon (poly-Si)/Si oxide (SiOx) to enhance passivation quality. The utilization of Cat-H demonstrates a substantial enhancement in surface passivation quality on crystalline Si (c-Si), resulting in an increase of the effective minority carrier lifetime (τeff) from 2.0 to 3.9 ms. The investigation reveals a dependency of τeff on the duration of Cat-H treatment: an initial rise followed by a plateau or slight decline. Secondary ion mass spectrometry (SIMS) measurements revealed the diffusion of H atoms into poly-Si and c-Si, which accumulate at the poly-Si/c-Si interface. This accumulation terminates dangling bonds in the poly-Si layer on the c-Si surface. Furthermore, the presence of an ultra-thin thermal Si oxide layer on the poly-Si layer formed during high-temperature annealing is crucial for protecting the film against etching induced by Cat-H.

Multiple scattering of 855 MeV electrons in amorphous and crystalline silicon: Simulations versus experiment

The angular distribution function of multiple scattering experienced by 855MeV electrons passing through an amorphous silicon plate and an oriented silicon crystal has been studied by means of relativistic molecular dynamics simulations using two types of the potentials that describe electron–atom interaction. The differences in the angular distributions of the beam particles in both media are analyzed. The results obtained are compared to the experimental data and to the results of Monte Carlo simulations.

Enhanced broadband IR absorption and electrical characteristics of silicon variably hyperdoped by sulfur (1018-1021 cm−3) by ion implantation/pulsed laser annealing

Spectral range of crystalline silicon absorption could be extended to near- and even mid-infrared region by its hyperdoping via ion-implantation technology, requiring the following thermal annealing for removing ion-induced defects, recrystallizing the crystalline structure and activating the doping impurity. In this article, the crystalline structure, chemical and electrical characteristics of sulfur-hyperdoped silicon layers with broadly variable impurity concentration (1018-1021 cm−3) and annealed by a nanosecond laser were investigated for the first time by Raman, energy-dispersion x-ray and infrared spectroscopy, as well as by van der Paw and Hall measurements, respectively. The most preferable sulfur concentration for silicon hyperdoping from the point of view of impurity optical and electrical activation was found to be 1020 cm−3.

Characterization of algerian desert sand as a raw material for solar-grade silicon production

The transition from fossil to clean power requires pure materials and technology. Silicon has semiconductor properties, it is the most important element in producing solar panels for electrical production, the high amount of pure silicon dioxide in the sand makes it a good raw material, economically rentable, and fewer procedures to refine it. The southwest of Algeria which has a hot, dry climate is categorized as a desert, representing an important reservoir of sunlight and an abundance of dunes, to explore and valorization of the potential of sand in this region as a raw material for solar-grade silicon production, the sand sample was gathered from Adrar province. Conventional physical and chemical characterization methods used to determine the nature and amount of existing oxides: X-ray diffraction, X-ray fluorescence to determine the rate of silicon dioxide existing in the sample, microscopy, and sieve analysis to find the shape of the grain. The results show that the ADRAR deposit has significant-quality silica sand due to its considerable silicon dioxide (SiO2) content, reaching 96%. However, it still requires extra mechanical and chemical processing, rendering it a valuable raw resource for the renewable energy industry.

Heavy Boron-Doped Silicon Tunneling Inter-layer Enables Efficient Silicon Heterojunction Solar Cells.

P-type hydrogenated nanocrystalline silicon (nc-Si:H) has been used as a hole-selective layer for efficient n-type crystalline silicon heterojunction (SHJ) solar cells. However, the presence of an additional valence band offset at the interface between intrinsic amorphous hydrogenated silicon and p-type nc-Si:H films will limit the hole carrier transportation. In this work, it has been found that when a heavily boron-doped silicon oxide layer deposited with high hydrogen dilution to silane (pB) was inserted into their interface, the fill factor of SHJ solar cells increases 3% absolutely because of the reduced valence band offset and the increased opportunity to provide a hopping tunnel assisted by the doping energy level and valence band tail states. Furthermore, the additional boron incorporation in intrinsic amorphous silicon adjacent to pB helps to enhance the built-in electric field, thus increasing the hole selectivity. By these means, the power conversion efficiency was improved from 23.9% to approximately 25%.

Design and Optimization of SiOx/AZO Transparent Passivating Contacts for High‐Efficiency Crystalline Silicon Solar Cells

Design and Optimization of SiOx/AZO Transparent Passivating Contacts for High‐Efficiency Crystalline Silicon Solar Cells

Boosting the effectiveness of a cutting-edge Ca3NCl3 perovskite solar cell by fine-tuning the hole transport layer

Ca3NCl3 has unique electrical and optical properties and shows great potential as an absorber for solar cells, offering a promising solution for enhancing efficiency and reducing costs. To determine the best device layout, this study uses a device combination of Ag/FTO/ETL/Ca3NCl3/HTL/Ni, including seven HTLs and one ETL with the SCAPS-1D simulator. To improve device configuration, consider variables including thickness, temperature, doping density, defect density, and series and shunt resistance. After optimizing device parameters, the Ag/FTO/SnS2/Ca3NCl3/MoO3/Ni device outperformed the other 6-HTLs (Cu2O, CuI, CuSCN, NiO, CuSbS2, and P3HT) based devices with a power conversion efficiency (PCE) of 28.13 %, an open circuit current (VOC) of 1.36 V, a short circuit current density (JSC) of 22.892 mA/cm2, and a fill factor (FF) of 90.36 %. This proposed solar cell has exceptional performance compared to conventional thin-film solar cells, highlighting Ca3NCl3 as an appealing solution for solar energy systems while reducing toxicity issues.

A Novel Approach for Thin 4H-SiC Foil Realization Using Controlled Spalling from a 4H-SiC Wafer

Porosifying the surface of a single crystalline silicon carbide (4H-SiC) wafer with the means of metal assisted photo chemical etching (MAPCE) promotes the adhesion of an electroplated nickel (Ni) layer. By utilizing a mechanical peel-off process, a Ni layer with tailored mechanical stress is peeled off such that also a thin layer of 4H-SiC is teared apart from the wafer as well.

Amorphous shear band formation in crystalline Si-anodes governs lithiation and capacity fading in Li-ion batteries

The cycling stability of Li-ion batteries is commonly attributed to the formation of the solid electrolyte interphase (SEI) layer, which is generated on the active material surface during electrochemical reactions in battery operation. Silicon experiences large volume changes upon the Li-insertion and extraction, leading to the amorphization of the silicon-interface due to the permeation of the Li-ions into the silicon. Here, we discover how generated non-hydrostatic strain upon electrochemical cycling further triggers dislocation and eventually shear band formation within the crystalline silicon core. The latter boosts the non-uniform lithiation at the silicon interface affecting the SEI reformation process and ultimately the capacity. Our findings are based on a comprehensive multiscale structural and chemical experimental characterization, complemented by molecular dynamics modelling. This approach highlights the importance of considering electrochemical, microstructural and mechanical mechanisms, offering a strategy for developing improved anode materials with enhanced cycling stability and reduced capacity loss.

Occupational hazards of crystalline silicon solar cell manufacturing industry

The wide use of crystalline silicon solar cells in the field of new energy is an important boost for China to achieve the environmental protection goal as soon as possible. However, the production and manufacturing processes of these cells give rise to various occupational hazards at workplace, thus posing health risks to workers. This review provided an overview of production processes of crystalline silicon solar cells, the characteristics of occupational health hazards (productive dust; physical factors, productive toxicant) and proposed occupational protection suggestions.