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High-performance wide-bandgap (WBG) perovskite solar cells are used as top cells in perovskite/silicon or perovskite/perovskite tandem solar cells, which possess the potential to overcome the Shockley-Queisser limitation of single-junction perovskite solar cells (PSCs). However, WBG perovskites still suffer from severe nonradiative recombination and large open-circuit voltage (Voc) losses, which restrict the improvement of PSC performance. Herein, we introduce 3,3'-diethyl-oxacarbo-cyanine iodide (DiOC2(3)) and multifunctional groups (C=N, C=C, C-O-C, C-N) into perovskite precursor solutions to simultaneously passivate deep level defects and reduce recombination centers. The multifunctional groups in DiOC2(3) coordinate with free Pb2+ at symmetric sites, passivating Pb vacancy defects, effectively suppressing nonradiative recombination, and maintaining considerable stability. The results reveal that the power conversion efficiency (PCE) of the 1.68 eV WBG perovskite solar cell with an inverted structure increases from 18.51% to 21.50%, and the Voc loss is only 0.487 V. The unpackaged device maintains 95% of its initial PCE after 500 h, in an N2 environment at 25°C. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have aroused vast attention and achieved unprecedented development. However, commercial utilization requires better reliability while maintaining high efficiency. Typically, the uncoordinated band energy configuration and structural defects led to recombination, these bottlenecks have seriously damaged the device performance and limited the further development of PSCs. In addressing those questions, researchers have provided various countermeasures including doping to trim the band structure and solvent engineering to modify the crystallization process and introducing reduced dimensional perovskite to maintain long‐term stability. Herein, a convenient carbazole analog doping strategy is reported by adding a certain amount of bromide‐substituted carbazole analog in the perovskite precursor which succeeded in modifying the surface morphology and optimizing the bandgap structure of the film, additionally maintaining considerable stability. As a result, a champion power conversion energy (PCE) of 22.25% is reached and preserved 85% of the initial PCE while stored in ambient air for more than 1200 h (around 30% relative humidity), and with low hysteresis. A simple but practical doping strategy to fabricate efficient and stable perovskite films in ambient air is provided. [ABSTRACT FROM AUTHOR]

[Display omitted] • A green, high-efficiency, and recyclable eutectic solvent was designed for the recycling of EOL PV modules. • Eutectic solvent was used to separate the EVA and Al layers in end-of-life photovoltaic modules. • EVA was separated by hydrothermal method and the separation mechanism was revealed. • The EVA separation rate remains 100% after 10 solvent cycles. Sustainable End-of-life (EOL) photovoltaic (PV) modules recycling is essential for achieving resource conservation and alleviating environmental issues. Ethylene vinyle acetate (EVA) adhesive films separation is a prerequisite for the realization of valuable component recovery of PV modules. However, the conventional wet chemical separation processes are usually accompanied by the challenges of low separation efficiency, high toxicity and difficult multiple recycling. Herein, a green, biodegradable, low-cost and recyclable deep eutectic solvent (DES) is firstly developed to efficiently separate EVA films in EOL PV modules. The high temperature stability and the acidic characteristic of DES can facilitate the separation of EVA film between component layers. At 175 ℃, the warping effect caused by the differential thermal contraction between the module component layers creates favorable conditions for the efficient reaction and separation by the DES. Additionally, the acidic medium reacts with the aluminum electrode layer of PV cells, which further enhances the separation efficiency of EVA films. The EVA separation rate reached 100%, the separation rate of the EVA containing aluminum (Al) up to 98.4% after 12.5 h at 175 ℃. Moreover, the developed DES exhibits excellent recyclable performance, the EVA separation rate remained 100% after 10 cycles. Compared to the traditional solvent toluene, DES has advantages in terms of economics, environmental impact, and efficiency. This strategy of design a green, biodegradable, low-cost and recyclable solvent to replace traditional solvents, and provides a promising route to efficiently separate EVA films in EOL PV modules. [ABSTRACT FROM AUTHOR]

The global exponential increases in annual photovoltaic (PV) installations and the resultant waste PV cells are an increasingly serious concern. How to dispose of and value-added recycling of these end-of-life PV cells has become an important issue in view of environmental or economic views. Herein, a potential sustainable development idea was put forward to recover silicon materials from stripped discarded photovoltaic modules based on wet leaching and nano-metal catalyzed etching to prepare porous silicon/carbon (PSi/Li/N@C) composite materials for the anode of lithium-ion batteries (LIBs). The results show that alkali/acid leaching can effectively remove the main impurities and obtain high purity silicon (∼99.86%). The resulting PSi/Li/N@C composite exhibits a high capacity of 685.2 mA h g−1 after 100 cycles at 2000 mA g−1. This work provides a potential application prospect and a new strategy for the value-added recycling of discarded PV cells. [ABSTRACT FROM AUTHOR]

Impurity removal, the purification process from metallurgical grade silicon (MG-Si) required to obtain solar grade silicon (SoG-Si), is crucial to the preparation of silicon-based solar cells. Some processes for boron removal by metallurgical method were reviewed. Secondary refining techniques, including gas blowing, slag treatment, plasma refining, solvent refining and other refining silicon techniques were summarized. The effects of gas species and slag systems on boron removal efficiency were emphatically discussed. Experimental and theoretical investigations show that a united technique of combining water vapor and oxygen gases blowing with slag treatment containing chloride or fluoride has achieved an amazing improvement for boron removal from molten silicon. Plasma refining and solvent refining also display high efficiency but acid leaching treatments, vacuum volatilization, electron beam and directional solidifications are hardly effective to boron removal. As for the potential industrial application of this united technique, the authors propose that some experimental and theoretical studies in dynamics should be further explored. [ABSTRACT FROM AUTHOR]

Surfaces nano-texturing has triggered off much attention for trapping sunlight to improve the efficiency of solar cells. Silicon nanowire (SiNWs) arrays, with excellent antireflection performance, will hopefully improve photoelectric conversion of solar cells, however, the deteriorated effective carrier lifetime seriously limits efficiency enhancement of solar devices. Until now, the effect of SiNWs structure on effective carrier lifetime remains unexplored. Herein, the effects of fabrication parameters on the morphology structure and effective carrier lifetime of textured mc-Si were studied in detail. We also firstly discover that the relationship of SiNWs arrays length and effective carrier lifetime shows the negative exponential relation. Moreover, the effects of ethanolic iodine (I-E) concentration, immersion time, and surface pre-conditioning (with and without native oxide) on surface passivation of SiNWs arrays were investigated. It is found that more effective surface passivation could be achieved for the SiNWs arrays with shorter length. Meanwhile, the HF dipping pretreatment is conducive for SiNWs passivation, and which is attributed to Si-H termination with lower dissociation energy. [ABSTRACT FROM AUTHOR]

In this work, an alternative metal-assisted chemical etching method is proposed to fabricate large-area uniform zigzag silicon nanowires. The effects of deposition time, etching time, HF concentration and H2O2concentration on the nanostructure of nanowires were systematically investigated. The results demonstrate the suitable preparation concentrations in the alternating etching process are HF([SI]/[SII] = 9.2 M/2.3 M) and H2O2{[SI]/[SII] = (0.04 M∼0.26 M)/(0.4 M∼0.65 M)}. Moreover, the anti-reflec-tion properties of the resulting zigzag SiNWs arrays have been studied, the average reflectance is almost lower than 10% at wavelength range of 200∼1200 nm. The superior anti-reflection performance of zigzag SiNWs shows a huge potential application in high-efficiency silicon solar cells. [ABSTRACT FROM AUTHOR]

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, H 2 O 2 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 > H 2 O 2 concentration > HF concentration. The comprehensive research results indicate that it is more beneficial for the nanowire arrays with tapering structure and the length of 13 μm 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. [ABSTRACT FROM AUTHOR]

• Two-step annealing enhances oxygen precipitation, and thus reduce the recovery of minority carrier lifetime during phosphorus gettering. • The effectiveness of phosphorus gettering is influenced by the size and quantity of oxygen precipitates. This study investigates the effects of single-step and two-step annealing processes on the formation of oxygen precipitates and their impact on metal impurity gettering in gallium-doped monocrystalline silicon. The research focuses on the competitive relationship between internal gettering by oxygen precipitates and external gettering through phosphorus diffusion. Experimental results show that two-step annealing generates larger and more abundant oxygen precipitates, enhancing the internal gettering effect and reducing the recovery of minority carrier lifetime after phosphorus gettering. Despite this, phosphorus diffusion gettering remains effective in improving minority carrier lifetime, although the degree of improvement depends on the size and quantity of oxygen precipitates. These findings offer valuable insights for optimizing the fabrication process of silicon-based solar cells. [ABSTRACT FROM AUTHOR]

The depressing texturation and stubborn directional saw marks on diamond wire sawing (DWS) polysilicon wafers has resulted in severe limitations for the mass application of DWS technology in PV market. Herein, a simple and low-cost copper-assisted chemical etching method was presented to controllably nano-texturing DWS polysilicon wafers. The work firstly reveals the adjustment of anion species in copper salts can readily control the nanostructure during the copper-catalyzed etching process. After etching, the obtained inverted pyramid structure can effectively reduce the reflectivity of the silicon wafer surface, the reflectance can be as low as 5.8% in the wavelength range of 300–1100 nm. Moreover, the surface saw marks are removed after etching, and the novel texture method guarantee the low recombination rates. The effective texturing method shows a promising potential application in the photovoltaic field. [ABSTRACT FROM AUTHOR]

The utilization of high-purity silicon (∼99.9999 %) is prevalent in the solar photovoltaic sector, and achieving a reduction in its cost has emerged as a pivotal engineering objective within the silicon solar industry. Recycling silicon from diamond wire saw silicon powder (DWSSP) is a promising solution to fulfill the continuously expanding of high purity silicon demand. Vacuum directional solidification technology using high-frequency electromagnetic induction heating was proposed to purify DWSSP for the first time efficiently. The silicon melt and gas interface reaction, as well as metal impurities' microsegregation in silicon ingot were observed. The effects of vacuum level and electromagnetic force on the separation of silicon and metal impurities were investigated using thermodynamics and electromagnetic mechanics. Results indicate that the content of oxygen in the silicon reduced from 30.91 wt% to 5.08 wt%, and the actual sample composition including for uptake of residual gas contamination steadily declined as the vacuum level increased from 600 Pa to 10 Pa. Vacuum electromagnetic directional solidification reduced the content of metal impurities from 641 ppmw to 29.80 ppmw, increases the proportion of crystalline silicon area, and makes the silicon lattice arrangement more regular. • Repeated directional solidification is more efficient for impurity removal. • The force applied on the metal impurity, magnetic force dominance was proposed first. • Metal impurities were reduced from 641ppmw to 29.80 ppmw. • Increasing the vacuum level helps to eliminate the volatile impurities. • Recycling of silicon cutting waste via a clean metallurgical route. [ABSTRACT FROM AUTHOR]

A new approach was proposed to prepare multi-products, high-purity Si powders, bulk Si, and Si/TiSi 2 materials (eutectic Si-Ti), simultaneously using inexpensive low-purity Si (99.3%) and metallurgical waste—Ti-bearing blast furnace slag. TiO 2 in Ti-bearing blast furnace slag was first reduced by Si to form a Si-Ti alloy which was then separated into high-purity bulk Si (99.97%) and Si/TiSi 2 materials (99.4%) using directional solidification. The bulk Si could be repeatedly recycled as a reductant, or further upgraded to prepare super-pure Si powders (99.995%) after acid leaching. The new approach shows many sustainable and economic benefits, such as no carbon gas emission, low acid consumption and Si loss, recyclable Si reductant, widely-used multi-products employing one approach, and rapid consumption of accumulated Ti-bearing blast furnace slag. • A new approach was proposed to clean up the Ti-bearing blast furnace slag. • Multi-products could be prepared simultaneously throughout one approach. • Most of Si could be recycled as reductant repeatedly. • Most of impurities could be removed to obtain high-purity Si and Ti materials. • Si-Ti alloy could be separated into bulk Si and eutectic Si-Ti alloy. [ABSTRACT FROM AUTHOR]

The installed capacity of solar photovoltaic power generation has grown rapidly in the last decades. With the rapid development of the photovoltaic industry, the demand for Si wafers, which are integral to solar cells, has grown dramatically. In the manufacture of Si wafers, the traditional loose abrasive sawing method (LAS) has gradually been replaced by the diamond-wire sawing method (DWS). However, during the diamond-wire wafer sawing process, approximately 35%−40% of the crystalline Si becomes diamond-wire sawing silicon waste (DSSW). Therefore, DSSW represents a resource worth recycling due to its low levels of impurities and high silicon content. Furthermore, recycling prevents DSSW from becoming environmental pollution and eliminates disposal costs. This review provides an overview of the recycling and reutilization of DSSW based on an extensive literature survey. In view of the rapid increase in DSSW production and current purification bottleneck of < 5 N, in-situ utilizations may be more feasible, such as the preparation of silicon containing alloys and functional ceramic materials, which not only frees from the complex purification process, but has a huge demand. Finally, based on the review, future prospects are proposed, aiming to identify research directions with significant potential in the resource utilization of DSSW and other silicon wastes. [Display omitted] ● DSSW with high silicon content represents a resource worth recovery and recycling. ● The proper purification process is a trade-off between cost and purity. ● In-situ utilizations of DSSW may be more feasible strategies. ● Modification facilitates real application of DSSW in lithium-ion batteries. ● DSSW has scalable applications in energy conversion and environmental catalysis. [ABSTRACT FROM AUTHOR]

Plating has long been recognized as a promising alternative to screen printing in commercial PV metallization due to its cost-saving and scaling-up potential. In this paper, we investigated the laser doping effects on plated contact formation. Critical parameters, such as laser power, focal position, and scanning speed, have been systematically analyzed by comparing their impacts on surface morphology, electrical properties, and plating results. Moreover, it was found the LD openings made by different laser resources would need different plating strategies. We have also successfully developed a baseline procedure integrating laser doping and hydrogenation passivation for bifacial plated PERC solar cells. Despite severe technical challenges in experimental conditions, up to 20.4% cell efficiency has been achieved, which evidentially demonstrates the commercial potential of plated contacts. • Plated contacts quality is strongly influenced by the Si surface conditions after laser doping. • The discontinuous openings caused by insufficient laser power should be minimized. • Laser doping conditions such as focus, power and speed should be carefully selected. • Different plating strategies may need for different laser resources doped samples. [ABSTRACT FROM AUTHOR]

The two-dimensional thin film, as an effective interface modification layer to improve the power conversion efficiency (PCE) of graphene/silicon (Gr/Si) heterojunction solar cells has attracted extensive attention recently. However, the complicated manufacturing process and specialized equipment requirements impede its broad application. Herein, carbon quantum dots (CQDs) fabricated under the mild reaction condition was first time used to modify Gr/Si devices interface structure. The effects of CQDs size distributions and coating thickness on J-V characteristics and the energy band structure of Gr/CQDs/Si solar cells were systematically analyzed. The results indicate that the PCE of resulting Gr/CQDs/Si solar cells could reach 9.97% when the thickness and sizes of CQDs interlayer are ∼26 nm and 4–7 nm, without any chemical doping, which is 6.8-times PCE than that of virgin Gr/Si solar cells. The CQDs interlayer serves as both an electron blocking layer and hole transport layer to reduce the carrier recombination, leading to a lower reverse saturation current as well as a larger V OC then improved the device performance. The enhanced PCE shows that the CQDs species have the potential applications in a cost-effective photovoltaic device. • Novel Gr/CQDs/Si solar cell is demonstrated through a simple solution process. • The cleaner graphene transfer method based on cyclododecane species was achieved. • The enhanced PCE of 9.97% was achieved for ∼26 nm thickness GQDs with interlayer size of 4–7 nm. • The energy band structure of Gr/CQDs/Si solar cells were systematically analyzed. [ABSTRACT FROM AUTHOR]