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Multidimensional simulations for diverse solar cells often encounter distinctive configurations, even when employing the same simulation software. The complexity and inefficiency of this process are further exacerbated when employing different simulators. From our extensive decade‐long experience in numerical simulations of diverse solar cells, we have identified ten common simulation steps intrinsic to typical electrical and optical simulations. Subsequently, we propose ten sets of variables that encompass all the relevant details required for these steps. To address the challenge of varying information requirements for each variable across different simulations, we assign a list, a versatile data type, to each variable. This approach, by design, enables concise, coherent, and flexible input, accommodating the unique demands of each simulation. However, to ensure unambiguous simulations, precise specifications for these variables are essential. Computer code has been successfully implemented to ensure adherence to specifications and expedite variable synchronization with Sentaurus, the de facto standard for device simulation. Within this framework, users are only tasked with editing variables in a plain text file, obviating the need for in‐depth knowledge of Sentaurus. This streamlines the prerequisites for engaging in numerical simulation significantly. Through thoughtful design considerations, we preserve the simulation capacity while simultaneously enhancing productivity considerably. This open‐source framework welcomes global collaboration within the photovoltaic community and has the potential to generate an extensive dataset for cost‐effective artificial intelligence training. [ABSTRACT FROM AUTHOR]

A novel additive-assisted acidic etching method is proposed to improve the etched morphology of the diamond wire sawn (DWS)-processed multicrystalline silicon (mc-Si) wafers. The proposed etching technique is a cost-effective method for surface texturization of DWS-processed mc-Si wafers, which can be used for large-scale production of Si-based solar cells. Moreover, the mechanism of additive-assisted etching is explained by decoupling the roles of surfactants and etching inhibitors. The additive-assisted etching of DWS-processed mc-Si wafers resulted in different morphology to the slurry wire sawn (SWS)-processed mc-Si wafers under optimized etching conditions. It has been observed that the etched morphology and reflectivity of DWS-processed mc-Si wafers are significantly influenced by the ratio of hydrofluoric acid (HF): nitric acid (HNO3) solution. High-quality etching morphologies have been obtained. Therefore, high-power conversion efficiency of 19.0% and open-circuit voltage (Voc) of 0.6386 V have been demonstrated by additive-textured DWS-processed Si-based solar cells. The improved power conversion efficiency and Voc can be ascribed to the reduced defect area of the wafer surface. In summary, the proposed additive-assisted acidic etching is an effective strategy to obtain the desired surface texturization of DWS-processed Si wafers for high-performance solar cell applications. [ABSTRACT FROM AUTHOR]

The intermediate band solar cell (IBSC) is one of the third-generation photovoltaic devices, whose theoretical conversion efficiencies can exceed the limit of Shockley and Queisser. The preparation of intermediate band (IB) materials is a key for IBSC applications. In this work, we explore to prepare IB materials by nickel (Ni) implantation in silicon (Si) followed by a rapid thermal process (RTP). The results show that the Ni concentrations in the effective doping zone exceed the Mott limit. The minority carrier lifetimes of the samples increase with the increase in Ni doping concentration. It proved that the non-radiative recombination is suppressed so that an IB is formed in Si. Moreover, the ion implantation of Ni can damage the Si lattice. The broken lattices can be recovered by controlling temperature and time of annealing. SEM shows the surface morphology of the materials, and X-ray diffraction (XRD) results show that the Si/Ni samples are single-phase structure. Furthermore, it is found that the IB for the Si/Ni samples is located at about 0.25 eV above the valence band edge. These results indicate that Ni-doped in Si can effectively form the intermediate band photovoltaic materials by ion implantation and RTP method. Arrhenius analysis of DLTS shows that Ni doping in silicon can effectively form an intermediate band by ion implantation and RTP method, and the intermediate band is located at about 0.25 eV above the valence band edge. [ABSTRACT FROM AUTHOR]

We have described the compositional engineering of mixed perovskite based on methyl- and polymeric-ammonium. The resulting perovskite films containing moisture-resistant 2D materials exhibit a maximum power conversion efficiency of over 15% with high reproducibility and good stability, offering greater tunability at the molecular level for material optimization. [ABSTRACT FROM AUTHOR]

Directional solidification is one of the most popular techniques for the massive production of multicrystalline silicon (mc-Si) for solar cell application due to its well-balanced high conversion efficiency and low production cost. The grown crystal suffers from several types of defects that significantly degrade the photovoltaic performance of solar cells, among which dislocation is the most critical caused by thermal stress. To examine the characteristics of thermal stress and associated fields, therefore, it is significant for the understanding and optimization of the cooling process. In the article, an integrated simulation tool has been developed and used to investigate heat transfer, fluid flow, and thermal stress during the cooling process of mc-silicon. The simulation results were further proved by experimental observations. According to the distortion energy theory, the total strain energy consists of the volumetric strain energy and the shear strain energy, and yield occurs when the shear component exceeds that at the yield point, which is the major cause of the dislocation. Therefore, by analyzing von Mises stress aligned in the direction that has to support the maximum shear load, the regions in the ingot with dislocation generation and multiplication can be evaluated. The displacement indicates the motion of the crystal ingot, and reveals the regions of deformation due to the existence of thermal stress from uneven cooling. Based on the complete investigation of the characteristics of thermal stress and associated displacement, the cooling process could be well comprehended and further optimized with the minimization of dislocation density. [ABSTRACT FROM AUTHOR]

• Spectral regulation methods were analyzed for cooling monofacial double-glass module. • A coupled thermal-electrical model was established to evaluate the performance. • Absorption loss of useful photons was considered for thermal and electrical simulation. • The radiative coating on the rear surface presented the optimal cooling effect. The monofacial double-glass photovoltaic modules are still seriously affected by the temperature effect. The coatings with spectral regulation characteristics are expected to reduce the impact from the temperature effect. A coupled thermal-electrical model was established to evaluate the thermal and electrical performance of the monofacial double-glass modules applied with different spectral regulation coatings, including sub-bandgap reflection coating, mid-infrared emission coating and a combination of the two coatings. The cooling effect and output power gain of these coatings on the front and rear surface of the modules were compared comprehensively. The results show that the most suitable cooling coating for the module is the mid-infrared emission coating (i.e. radiative coating) on the rear surface when absorption loss of solar cell caused by spectral regulation coating was considered. Thus, we prepared the radiative coatings of TPX/SiO 2 by doping SiO 2 particles into the TPX polymer matrix. The thermal and electrical performances of the modules applied with different coatings on the rear surfaces of PV modules were calculated to optimize the coating parameters, such as thickness, size and volume fractions of SiO 2 particles. The results reveal that the module applied with the TPX/SiO 2 coating (size: 50 nm, volume fraction: 5 vol%, thickness: 60 μm) on the rear surface exhibited the lowest temperature and the highest output power. In the outdoor experiments, the radiative coating realized the cooling effect of ∼1 °C, and the efficiency improvement of 0.21 %. This work demonstrates that radiative cooling coating on the rear surface can bring PV module heat dissipation. Further research and development of radiative coatings would improve the cooling and electrical performances of PV module. [ABSTRACT FROM AUTHOR]

The mottling phenomenon refers to the appearance of irregular dark patterns on HF–HNO 3 acid etching textured multicrystalline silicon (mc-Si) wafers. The mottles have been identified as clusters of dislocation etch pits. In the acidic texturization, conditions favoring light reflectivity reduction usually lead to enhanced mottling. In a belief of adverse effect of the mottles to cell performance, light reflectivity reduction is more or less compromised in industry to avoid the mottling. The present study aims to identify whether appearance of the mottles alone really adversely affects the wafers minority carrier lifetime. Both serial examinations of an acid etched mc-Si wafer sample and parallel examinations of neighboring pairs of mc-Si wafer samples etched in acids of different HF/HNO 3 ratios were carried out. The results show that development of the mottling, i.e., growth of dislocation etch pits, does not deteriorate mc-Si wafers in their minority carriers lifetime; rather it even slightly increases the lifetimes. Light reflectivity measurement and modeling show that the mottles can contribute to reduction of light reflectivity, and ~3% relative reduction of reflectivity is expected for multicrystalline silicon wafers of ordinary level of dislocation density. Removal of the defected zone surrounding a dislocation by the etching is postulated as a reason for the observed mottling-enhancement of the lifetime. It is further postulated that, in texturization of mc-Si wafers for cell production, instead of compromising light reflectivity reduction to avoid the mottling, it may be better to pursue lower light reflectivity, allowing some extent of the mottling. Meanwhile, more attention should be paid to compatibility of the cone-shaped dislocation etch-pit with grid printing of solar cells. [ABSTRACT FROM AUTHOR]

Grinding as a pre-treatment method for HF-HNO 3 -H 2 O solution etching of diamond wire sawn (DWS) multi-crystalline (multi-Si) silicon wafers was proposed and researched. Significant improvement in morphological uniformity and decrease in light reflectivity of the wet acid etched surface textures were achieved with the pre-treatment. The photoelectric-conversion efficiency gain of solar cells fabricated with the pretreated DWS multi-Si wafers was 0.32%, compared to solar cells fabricated with the same batch of untreated wafers in an identical production line. The grinding pre-treatment was observed to restructure the superficial layer of DWS multi-Si wafers. The surface modification layer was believed to be more easily reacted with the wet acid etching solution, proving responsible for the improvement of photoelectric-conversion efficiency of solar cells. This method could provide a new research idea for the wet acid texturization of DWS multi-Si wafers. [ABSTRACT FROM AUTHOR]

Improvement of amorphous silicon/crystalline silicon heterojunction solar cells (HJT cells) by electro-thermal processing with the injected current greater than the short-circuit current (Isc) of the cells has been investigated. The results showed that, for the cells with a base efficiency level of 22.5% and an area of 244.32 cm2, forward current injections of 30–80 A yielded ∼0.60% abs efficiency gain on average, which was almost twice that by a 10 A injection. The improvement was mainly attributed to increased open-circuit voltage (Voc) and fill factor (FF). The lower the initial value of Voc or FF, the greater the increase was, and Isc was rather stable throughout the electro-thermal processing. Higher temperature and greater current are believed to favor the kinetics of the process. Light-thermal processing of HJT cells under electric field conditions of open-circuit, short-circuit, forward-voltage bias, and reverse-voltage bias were carried out. The results indicated that changes in the electric field do not affect the improvement of HJT cells by the light-thermal processing. It is encouraging that no considerable contact damages were found on the HJT cells electro-thermally processed in stacks, while the improvement was well kept, demonstrating the potential applicability of the electro-thermal processing for HJT cells on a production scale. • On a batch of HJT cells with efficiency around 22.5%, the maximum average efficiency gain of 0.60%abs was obtained. • With 80 A current injection at 185 °C, the maximum efficiency gain can be reached within 3 min. in cells. • No considerable damages were detected in cells after being coin-stacked and subjected to current injection of 30A. [ABSTRACT FROM AUTHOR]

Highlights • Low cost and high efficiency multicrystalline silicon solar cells can be achieved. • Bifacial power generation capacity achieved by simple process. • A rapid thermal annealing used to improve cell performance furtherly. Abstract It is important to find a more cost-effective way of putting multicrystalline silicon as the mainstream silicon materials for industrial silicon solar cell fabrications. This paper presents a low-cost, bifacial multicrystalline PERC (passivated-emitter and rear cell) cells approach. Instead of the traditional PERC cells with full-area aluminum back surface field, cells rear-side is treated with aluminum grid pattern and firing-through aluminum paste. Thus, the bifacial power generation is obtained, and the laser ablation step is avoid and the consumption of aluminum paste is reduced. Rear surface passivation and metal contact are optimized via enhancing the corrosiveness of aluminum paste, matching the passivation film and improving the co-firing process. LID (light induced degradation) phenomenon of this kind of cell is controlled within a reasonable range by both light injection annealing and electric injection annealing. In addition, an anneal at 385 °C can further increase the cell efficiency by 0.2% absolute. The average batch efficiency of the front-side can reach 19.63%. The champion cell efficiency is 19.86% on the front and 13.65% on the rear. [ABSTRACT FROM AUTHOR]

It has been known that amorphous silicon/crystalline silicon heterojunction solar cells (HJT cells) can be improved by light-thermal processes. The present work aims to acquire a further understanding of the effect of illumination intensity and temperatures in a broader range and the roles of light and heat in the improvement. Naked HJT cells without grids were used for more reliable measurement of minority carrier lifetimes. Experiments of light-thermal processes of the naked HJT cells, with lighting from red LED arrays and heating/cooling from a thermal stage/air fan, have been carried out, with the illumination intensity ranging in 1–8 kW/m2 and cell temperature ranging in 160–220 °C. The higher illumination intensity results in longer lifetimes of the cells, the optimum cell temperature appeared to be around 180 °C, with the lower temperature needing a longer processing time to reach peak lifetime increment, while the higher temperature tends to degrade the passivation of the cell. The cell temperature of 180 °C was then chosen for the light-thermal processes of commercial HJT cells of ∼23.8% efficiency on a pilot line, with 12 kW/m2 red illumination. An average efficiency gain of 0.77% abs and a maximum gain of 0.87% abs have been achieved, with a processing time of 80 s. It is encouraging that the light intensity required is much lower than the previously reported level for similar improvement, indicating much lower power consumption for industrial application of the process. Through semi-shading experimentation of the light-thermal process, it is postulated that the effect of illumination does not rely on the direct effect of the injected photons, but possibly resulted from the effect of light-generated carriers. [ABSTRACT FROM AUTHOR]

The intermediate band solar cell (IBSC) is a kind of novel photovoltaic device with very high efficiency limit. The intermediate band (IB) material is a key factor for fabricating high-performance IBSC. We explore to prepare IB material by Co implantation in silicon followed by a rapid thermal process (RTP). The results show that an IB is successfully formed in Si layer. The IB is located at about 0.3 eV above the valence band edge. Moreover, no impurity phase is formed in the samples. Our results indicated that it is effective to form IB materials with the combination of ion implantation and RTP method. This approach is attractive since the RTP technique is beneficial to fabricate IB materials with thick impurity layers and convenient to use for mass production. [ABSTRACT FROM AUTHOR]

The research of intermediate band solar cells has become a hot spot in the field of photovoltaics. The preparation of intermediate band materials is a key for intermediate band solar cell applications. In this paper, we attempted to prepare the intermediate band photovoltaic materials with supersaturated vanadium-doped silicon by ion implantation and rapid thermal treatment (RTP). The results show that the RTP technique can recover the damage to the lattice and morphology caused by ion implantation and can promote carrier activation and mobility. Moreover, the near infrared absorption of the samples is significantly enhanced, which indicates that some subband absorptions have been implemented in the samples. Furthermore, the minority carrier lifetime increases with increasing the dose of vanadium ion. This agrees with the intermediate-band prediction, suggesting an intermediate band is formed in the vanadium-doped silicon. In addition, the Arrhenius analysis shows that the intermediate band is located at about 0.43 eV below the conduction band edge of silicon. Our results indicated that the IB photovoltaic materials can be effectively prepared by vanadium-implantation in silicon and RTP technique. • We introduced vanadium into Si to synthesize the intermediate band materials. • The minority carrier lifetimes increase with the increase of vanadium ion dose. • The NIR absorption of the samples is enhanced due to the sub-absorptions. • The IB of Si:V materials locates at ∼0.43 eV below the conduction band edge. [ABSTRACT FROM AUTHOR]

Clearly visible saw marks are a significant barrier to commercial use of diamond wire sawn multicrystalline silicon wafers for solar cells. Two types of saw marks on the diamond-cut multicrystalline silicon wafers are identified—the millimeter scale round-run fringes caused by round-running of the saw wires, and the micron scale scratches caused by scribing of the diamond tips. The latter consists of smooth and shiny grooves covered by a thin layer of amorphous phase. The micro-roughness of diamond-cut wafers is actually ~25% less than that of the conventional slurry-cut wafers. The reason for the visibility of the round-run fringes to naked eyes, and for the relatively rough appearance of diamond-cut wafers, is the visual enhancement from the shiny scratches. Therefore, the key to remove the round-run fringes is to roughen the smooth grooves, as flattening the very slightly sloped fringe zones is very difficult due to lack of chemical contrast over them. Acid-etching texturization cannot remove the saw marks on the diamond-cut silicon wafers. Alkaline-etching can only remove the saw marks on grains near (0 0 1) orientation. A vapor blast etching method has been attempted. The preliminary result is encouraging—complete removal of the saw marks has been achieved, along with a good surface texture, which reduces the light reflectivity to 19%. [ABSTRACT FROM AUTHOR]

In this work, we proposed a new method of seed recycling for casting monocrystalline silicon ingots. Different regions at the bottom of the monocrystalline silicon bricks were cut for controlling its size and crystal defects, which were used as recycled seeds and reasonable splicing to induce grain boundaries. The results showed that the recycled seeds with higher concentration of metal impurities will result in a longer red zone and the yield of mono-Si ingot would be slightly decreased. The defect density in the recycled seeds increased significantly, but decreased greatly during the seeding and growth. The defect distribution in PL images at the top of ingots grown with recycled seeds was similar to that of ingots grown with new seeds. Furthermore, the average cell efficiency of the solar cells fabricated by the wafers grown with recycled seeds was only 0.1% different from that of the wafers grown with new seeds. Therefore, this low-cost seed recycling method is of great significance for reducing the cost of cast monocrystalline silicon. • The recycled seeds with high metal concentrations would increase the red zone length at the ingot bottom, which is also confirmed by the numerical simulation. • The defect density in the recycled seeds is significantly increased, but decreased greatly due to the barrier of seeding interface. • The average cell efficiency of the wafers grown with recycled seeds was comparable to that of the wafers grown with new seeds. [ABSTRACT FROM AUTHOR]

This work introduces a novel design of oxide-free and low-cost diffusion barrier layer to reduce the contamination from SiO 2 crucible. The diffusion barrier layer consists of two Si 3 N 4 layers and a middle layer of high purity Si powder. The diffusion barrier layer was applied for casting crystalline silicon with different types of seeds and the influence on impurity diffusion in crucible was analyzed. The results show that the diffusion barrier layer could effectively reduce the solid phase diffusion distance of metal impurities from crucible and significantly reduce the low minority carrier lifetime region at the bottom and edge of cast crystalline silicon ingot. Meanwhile, the performance of solar cells made of the wafers at the bottom and edge of ingots are obviously improved. Therefore, this non-oxide diffusion barrier layer could significantly improve ingot quality and increase ingot yield in industrial production. • A novel design of non-oxide and low-cost diffusion barrier layer has introduced to reduce the contamination of SiO 2 crucible. • The diffusion barrier layer can effectively reduce the solid diffusion distance of metal impurities in the crucible. • The reduction of red zone length significantly improves the cell efficiency of wafers in the bottom region of crystalline silicon. [ABSTRACT FROM AUTHOR]

• Si particles embedded in the Si 3 N 4 layer as cost-effective seeds for growing high- quality mc-Si was introduced. • The ingot yield was increased by approximately 7% due to the significantly reduced red zone length. • The solar cells fabricated with the experiment wafers can achieve high cell efficiency and low LID level. This work proposes to utilize Si particles embedded in Si 3 N 4 layer as low-cost seeds to produce high-quality multi-crystalline silicon (mc-Si) ingot by full-melting process. The nucleation mechanism and its effects on minority carrier lifetime distribution, PL defects and oxygen concentration were studied. The results show that the incompletely melted silicon particles embedded in the Si 3 N 4 layer can effectively nucleate fine grains with uniform size and few defects. The yield of experiment ingot can be significantly increased due to the quite short length of bottom red zone. Finally, the prepared solar cells can also achieve high conversion efficiency and show low light-induced degradation (LID) value. [ABSTRACT FROM AUTHOR]