Surface Passivation Techniques for Reduced Recombination Loss in Solar Cells

Solar cell design with improved efficiency by optimizing electrode contact to the passivation contact structure. The cell has alternating regions on the surface with passivation contacts formed only on some regions. Secondary passivation contacts are formed on the primary contacts aligned with the uncovered regions. Electrodes fully cover the secondary contacts to increase electrical contact compared to just the top surface. This improves carrier collection and reduces parasitic light absorption compared to full coverage on all contacts.

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Photovoltaic cell design with improved anti-PID performance and power generation efficiency for solar modules. The cell has a rear passivation layer stack with aluminum oxide (Al2O3) having a thickness of 4-20 nm, silicon oxynitride (SiOxNy) with Si>O and 1-30 nm thickness, and silicon nitride (Si3N4) with Si>N and 50-100 nm thickness. This rear stack reduces interface recombination, PID effects, and improves light extraction compared to standard rear passivation layers.

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Method for preparing a solar cell with improved efficiency by forming tunneling passivation structures on both the front and back surfaces. The method involves oxidizing a portion of the back surface passivation layer to create a mask, then etching through the mask to form the back surface tunneling passivation structure. This prevents damage to the textured surface during etching. The front surface tunneling passivation structure is formed separately. This ensures consistency in texturing between the contact and non-contact regions.

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A perovskite solar cell with improved performance through a semi-opening passivation contact structure. The cell features a charge transport layer and a perovskite layer separated by an insulating or low-conductivity material layer, which can be continuous or discontinuous. This structure enables efficient passivation of interface defects without hindering carrier transport, thereby enhancing open-circuit voltage and fill factor while reducing non-radiative recombination loss.

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Solar cell design to improve efficiency by reducing front surface recombination. The solar cell has front surface field regions spaced apart from each other. Each front surface field region corresponds to a P-type or N-type conductive region on the back surface. Front and back passivation layers are used. This allows Coulomb field passivation by the front surface fields to drive carriers away from the front surface, while the back passivation prevents recombination. The front surface passivation is less affected by the front fields.

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A tunnel oxide passivated contact (TOPCon) solar cell with improved efficiency, comprising a tunnel oxide layer and a doped polysilicon layer, wherein the doped polysilicon layer is replaced with a transparent conductive oxide (TCO) layer, and a first passivation layer is formed on the TCO layer. The TCO layer is preferably a doped metal oxide, such as aluminum-doped zinc oxide, and the first passivation layer is preferably aluminum oxide or silicon nitride. The solar cell exhibits improved fill factor and efficiency compared to conventional TOPCon cells.

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A modified tunnel oxide layer for passivated contact (TOPCon) solar cells that improves device performance compared to conventional tunnel oxide layers. The modified oxide has a higher Si4+ content and is treated with plasma to enhance the bonding and stability of the oxide surface. This results in better passivation and lower contact resistance compared to conventional tunnel oxides. The modified oxide preparation involves growing a thin SiOx layer, followed by surface treatment with a plasma containing both hydrogen and oxygen. This modifies the oxide composition and structure to improve passivation and device performance when used in TOPCon solar cells.

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Heterojunction photovoltaic cells with improved efficiency through the use of silicon carbide layers in the front passivation layer and n-type layer, while maintaining amorphous silicon in the rear passivation layer and p-type layer. The silicon carbide layers reduce parasitic absorption of sunlight, increasing cell efficiency.

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Photovoltaic cell design with improved reliability by reducing series resistance. The cell has a tunnel oxide layer on the substrate with nitrogen and phosphorus, a doped surface field in the substrate contacting the tunnel oxide, and a metal electrode on the tunnel oxide. This configuration provides a good interface passivation effect even if the metal electrode penetrates the tunnel oxide. The doped surface field also enhances carrier transmission and reduces series resistance.

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A solar cell with reduced recombination losses at side edges, comprising a substrate, a doped conductive layer, a first passivation film layer, and a first dielectric layer. The first passivation film layer completely covers the side surfaces of the substrate, and a second passivation film layer is stacked on the surface of a passivated contact layer facing away from the substrate. The second passivation film layer is made of a material including at least one of SiNx, SiONx, and SiOx.

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A solar cell with improved light absorption efficiency and isolation properties, comprising a silicon substrate, a passivation layer, a three-layered antireflection film, and a tunneling dielectric layer. The antireflection film includes a silicon nitride layer, a silicon oxynitride layer, and a silicon oxide layer, each with specific composition ratios. The passivation layer is an aluminum oxide layer with a specific composition ratio, and the tunneling dielectric layer is formed on the rear surface of the substrate.

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A solar cell with improved light absorption efficiency and isolation properties, comprising an N-type silicon substrate, a passivation layer, a three-layered antireflection film, and a tunneling dielectric layer. The antireflection film includes a silicon nitride layer, a silicon oxynitride layer, and a silicon oxide layer, stacked in that order. The passivation layer is an aluminum oxide layer between the substrate and the antireflection film. The tunneling dielectric layer is on the rear surface of the substrate.

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Solar cell with enhanced passivation performance through a multi-layered structure. The cell comprises a semiconductor substrate, a hole transport layer, an electronic transport layer, a first passivation layer, and a second passivation layer. The first passivation layer is positioned between the hole transport layer and the semiconductor substrate, while the second passivation layer is applied between the electronic transport layer and the second surface of the semiconductor substrate. This dual-layer architecture enhances the passivation performance by providing a dense, uniform barrier between the active layers and the substrate surface.

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A solar cell with reduced recombination losses at side edges, comprising a substrate, a doped conductive layer, a first passivation film layer, and a first dielectric layer. The first passivation film layer completely covers the side surfaces of the substrate, and a second passivation film layer is stacked on the side of the passivated contact layer facing away from the substrate. The second passivation film layer is made of a material including at least one of SiNx, SiONx, and SiOx.

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A solar cell and method for manufacturing a solar cell that improves efficiency and performance by optimizing the metallized region. The cell includes a semiconductor substrate, emitter, front passivation layer, tunneling layer, doped conductive layer, rear passivation layer, and electrodes. The doped conductive layer has a first region with lower oxygen content for metallized areas and a second region with higher oxygen content for non-metallized areas. The tunneling layer and doped conductive layer are optimized to reduce contact resistance and improve passivation performance.

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A solar cell with improved light absorption efficiency, comprising a substrate, a passivation stack, a tunneling oxide layer, and a doped conductive layer. The passivation stack includes an oxygen-containing dielectric layer, a first passivation layer, and a second passivation layer, with the second passivation layer comprising a silicon oxynitride material. The first passivation layer has a higher refractive index than the second passivation layer, and the oxygen-containing dielectric layer has a thickness of 1-15 nm. The solar cell achieves a darker appearance through optimized passivation layer composition and thickness.

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A method for preparing a passivation layer for solar cells that balances passivation effect and manufacturing efficiency. The method involves forming a first passivation layer on the front surface of a substrate using a first preparation technique, and then forming a second passivation layer on the back surface of the substrate using a second preparation technique. The second passivation layer has a higher hydrogen content and/or thickness than the first passivation layer, which is formed on both the front surface and peripheral side surfaces of the substrate.

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A passivation layer for perovskite solar cells that improves efficiency and stability by using a novel organic compound with a carbazole backbone. The compound, synthesized through a multi-step process, forms a flat and uniform film that effectively passivates metal ions at the interface between the perovskite layer and the hole transport layer. This reduces charge recombination and enhances carrier extraction, leading to improved power conversion efficiency and stability of the solar cell.

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Nonradiative recombination losses occurring at the interface pose a significant obstacle to achieve high-efficiency perovskite solar cells (PSCs), particularly in inverted PSCs. Passivating surface defects using molecules with different functional groups represents one of the key strategies for enhancing PSCs efficiency. However, a lack of insight into the passivation orientation of molecules on the surface is a challenge for rational molecular design. In this study, aminothiol hydrochlorides with different alkyl chains but identical electron-donating (-SH) and electron-withdrawing (-NH

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Solar cell with a hydrogen-containing passivation layer on the front contact that exhibits increasing electrical conductivity from the inside to the outside in at least three stages, enhancing light absorption and charge carrier collection efficiency.

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A method for manufacturing photovoltaic cells that improves efficiency by passivating native edges of the initial cell. The method involves removing the active layers from the native edges and applying a dedicated passivation layer to each edge, rather than relying on the initial passivation layer. This approach enables the creation of high-efficiency photovoltaic sub-cells, particularly suitable for shingle interconnection technology.

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Non-radiative recombination losses limit the property of perovskite solar cells (PSCs). Here, a synergistic strategy of SnSe

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Edge recombination is considered hard to avoid entirely in silicon (Si) solar cells as well as Si-base solar devices, hindering their future commercialization. However, such an important issue in perovskite/silicon (PK/Si) tandem solar cells has not attracted much attention. Herein, a low-temperature, non-vacuum liquid-based edge passivation strategy (LEPS) to improve the power conversion efficiency (PCE) of PK/Si tandem solar cells is proposed. The minority carrier lifetime (eff) of the PK/Si tandem sample with 495.8 s significantly enhances to 739.7 s after passivating the Si sub-cell edge recombination. The open circuit voltage (VOC) of the PK/Si tandem solar cell increases by up to +3.8%abs from the initial state after LEPS treatment due to edge passivation, leading to the PCE of the PK/Si tandem solar cell increases by up to +1.2%abs. Finally, a monolithic PK/Si tandem cell with a PCE of 29.48% was achieved by further utilizing the LEPS, which opened up a simple and effective avenue for enhancing the PCE of PK/Si tandem solar cells and further promoting a higher photovoltaic ... Read More

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A solar cell with improved passivation effect on the front surface, comprising a silicon substrate with P-type and N-type regions on the back surface, front surface field regions on the front surface, and front and back passivation layers. The front surface field regions are selectively formed over the P-type and N-type regions, rather than covering the entire front surface, to minimize interference with the passivation layers and enhance carrier collection efficiency.

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Solar cell with improved passivated contact structure on the light-facing surface, comprising a tunneling layer, a phosphorus-doped polysilicon layer, a front phosphorus silicate glass layer, and a silicon nitride layer. The front phosphorus silicate glass layer is formed by thermally oxidizing the phosphorus-doped polysilicon layer, and the silicon nitride layer is formed with hydrogen filling. The structure reduces contact recombination and parasitic absorption on the light-facing surface, enhancing the solar cell's open-circuit voltage, short-circuit current, fill factor, and photoelectric conversion efficiency.

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Solar cells with improved passivation and anti-reflection performance, comprising a silicon substrate with a first passivation layer of aluminum oxide or silicon oxide and a first anti-reflection layer of silicon nitride, silicon oxynitride, or silicon oxide, deposited using high-temperature processes that enable dense and uniform films with enhanced corrosion resistance.

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A photovoltaic cell with improved passivation and carrier transmission efficiency, comprising a substrate, a passivation layer with alternating high and low doping concentration regions, and electrodes. The high doping concentration regions have a gradual doping concentration decrease towards the low doping concentration regions, and the low doping concentration regions have a doping concentration less than the minimum in the high doping concentration regions. This design enables a gradual potential barrier reduction for carrier transmission, prolonging minority carrier lifetime and enhancing passivation effect, while also reducing majority carrier transmission resistance.

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Abstract With the improvement of surface passivation, bulk recombination is becoming an indispensable and decisive factor to assess the theoretical limiting efficiency ( ) of crystalline silicon (cSi) solar cells. In simultaneous consideration of surface and bulk recombination, a modified model of evaluation is developed. Surface recombination is directly depicted with contact selectivity while bulk recombination is revised on the aspects of ideality factor and wafer thickness. The of the doubleside silicon heterojunction (SHJ) and doubleside tunnelingoxide passivating contact (TOPCon) solar cells are numerically simulated using the new model as 28.99% and 29.19%, respectively. However, the of singleside TOPCon solar cells, the more practicable scenario, is only 27.79%. Besides, the of the doubleside SHJ solar cells would exceed the doubleside TOPCon solar cells if the recombination parameter of the noncontacted area is higher than 0.6 fA/cm 2 , instead of perfect passivation. Our results are instructive in accurately assessing efficiency potential and accordingly optimizing ... Read More

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A surface passivation strategy using CTPC molecules is proposed to enhance the efficiency of inverted perovskite solar cells to 24.63%.

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Knowledge regarding the temperature dependence of the surface recombination at the interface between silicon and various dielectrics is critically important as it 1) provides fundamental information regarding the interfaces and 2) improves the modeling of solar cell performance under actual operating conditions. Herein, the temperature and carrierdependent surface recombination at the siliconoxide/silicon and aluminumoxide/silicon interfaces in the temperature range of 2590 C using an advanced technique is investigated. This method enables to control the surface carrier population from heavy accumulation to heavy inversion via an external bias voltage, allowing for the decoupling of the bulk and surface contributions to the effective lifetime. Thus, it offers a simple and versatile manner to separate the chemical passivation from the chargeassisted population control at the silicon/dielectric interface. A model is established to obtain the temperature dependence of the capture cross sections, a critical capability for the optimization of the dielectric layers and the investiga... Read More

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Passivation defects and reducing charge recombination are of great importance in enhancing 2D perovskite solar cells' (PSCs) performance. Herein, a novel additive (TEMPIC) is introduced into 2D PSCs to improve photovoltaic properties of the device, which are mainly attributed to passivated trap-states and reduced charge recombination in device.

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Abstract As the conversion efficiency of solar cell approaching its theoretical limits, reducing the power loss during the collection and transmission process is a promising way to improve the performance of solar cell. Cleaved edges create recombination centers, causing up to 0.8% abs (absolute efficiency) of power loss or even more for 156 156 mm silicon solar cell. Due to the complexity of edge passivation technique, alternative methods are desired. This article proposes a method to minimize this problem. It is found that most of the recombination current of edge comes from the recombination near the contact and the space charge region (SCR). As a result, keeping the cleaved edge a certain distance away from the contacts and SCR can improve performance effectively. On the other hand, contactless edge can reduce the recombination from the SCR without extra manufacturing difficulty. The results indicate the edge recombination loss can be reduced to less than 0.4% abs after the distance is optimized appropriately.

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Solar cell design with improved passivation to enhance photoelectric conversion efficiency. The solar cell has a unique passivation layer structure with higher atomic packing density and thinner average thickness on the surface closest to the substrate compared to the outer passivation layer. This inner passivation layer is formed using atomic layer deposition (ALD) for better coverage and lower defect density compared to plasma enhanced chemical vapor deposition (PECVD). The outer passivation layer is formed using PECVD for faster deposition. The inner ALD passivation layer provides initial surface passivation, followed by the thicker PECVD layer for additional passivation and coverage.

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Solar cell design and manufacturing process to improve efficiency by reducing recombination at the cell edges. The cell has an anti-reflection layer or second passivation layer extending onto some of the side surfaces in addition to covering the top and bottom surfaces. This reduces recombination at the edges compared to cells where only the top and bottom surfaces are passivated.

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A photovoltaic cell with improved passivation and efficiency, comprising a substrate with a tunneling layer, field passivation layer, and first electrode on its rear surface. The field passivation layer has a first doping region with a higher doping curve slope than a second doping region adjacent to the tunneling layer. The tunneling layer's doping curve slope decreases towards the substrate. The substrate includes a second doping element, and the cell further includes an emitter, second passivation film, and second electrode on its front surface.

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A method for improving the efficiency of P-type passivated emitter and rear cell (PERC) solar cells by introducing a novel laminated passivation structure. The structure comprises a silicon substrate with a first SiO2 film, an Al2O3 layer, a SiOxNy film, and a first SiNx film sequentially deposited on the back surface. The aluminum back field passes through these layers to connect with the substrate, reducing recombination and increasing long-wave reflection. The structure enables a 1% or more efficiency improvement in PERC cells, with the potential to further enhance efficiency beyond current limits.

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A photovoltaic cell with improved anti-PID performance and power generation efficiency, comprising a substrate, a front-side passivation layer and anti-reflection layer, and a rear-side passivation layer, polarization phenomenon weakening layer, and silicon nitride layer. The rear-side passivation layer includes an aluminum oxide layer with a refractive index of 1.4-1.6 and thickness of 4-20 nm, the polarization phenomenon weakening layer includes a silicon oxynitride layer with a refractive index of 1.5-1.8 and thickness of 1-30 nm, and the silicon nitride layer has a refractive index of 1.9-2.5 and thickness of 50-100 nm.

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A solar cell with improved passivation efficiency, comprising an N-type substrate, a P-type emitter, and a multi-layer passivation structure on the front surface. The passivation structure includes a first silicon oxynitride layer, a silicon nitride layer, and a second silicon oxynitride layer, with refractive indices optimized for interface passivation and light management. The structure eliminates the need for aluminum oxide, which can compromise passivation in N-type cells, and enables efficient production of high-performance solar cells.

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Solar cell and photovoltaic module with improved PID resistance, comprising a substrate, a first passivation stack with a first oxygen-rich dielectric layer having an oxygen atomic fraction of 40-70%, a first silicon-rich dielectric layer with an oxygen atomic fraction of 0-10%, a second oxygen-rich dielectric layer with an oxygen atomic fraction of 30-80%, and a second silicon-rich dielectric layer with an oxygen atomic fraction of 0-10%, and a second passivation layer.

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A modification layer for hybrid perovskite solar cells that enhances efficiency by passivating defects and optimizing energy levels at the interface between the perovskite layer and the underlying composite layer. The modification layer is formed from small organic molecules or polymers with specific functional groups that interact with both the composite layer and the perovskite layer to improve charge transport and reduce recombination.

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Solar cell with improved light absorption efficiency, comprising a substrate with a front and rear surface, a dielectric passivation layer on the front surface, a silicon nitride layer with a specific nitrogen-to-molybdenum ratio, and a silicon oxynitride layer with a specific oxygen-to-nitrogen ratio, and a tunneling oxide and doped conductive layer on the rear surface.

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A solar cell structure that mitigates potential-induced degradation (PID) in multiple module configurations. The structure comprises a silicon substrate with a lower surface coated with an aluminum oxide layer, followed by a first silicon oxynitride layer, a silicon nitride layer, and a second silicon oxynitride layer. This configuration prevents PID effects that can damage the solar cell and reduce efficiency.

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A method for improving the performance of n-type heterojunction solar cells through a novel annealing process that involves illuminating the cell surface with high-intensity light at temperatures above 200°C, while actively cooling the cell to prevent overheating. The process enhances the open-circuit voltage and fill factor of the cells, with improvements attributed to improved surface passivation.

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Solar cell design with textured rear surface and matching front surface texture to improve efficiency and reduce contact resistance. The rear surface has a closely spaced multi-level texture to improve open circuit voltage. The front surface has a texture with larger features. This matching reduces contact resistance when the rear texture is polished. The cell has a tunnel oxide layer between the textured surfaces for passivation. The rear texture density prevents tunnel oxide damage. The front texture size limits contact resistance increase from polishing. The rear texture spacing and front texture size are optimized for balance.

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Solar cell with enhanced passivation and conversion efficiency through a novel donor material film layer. The film is manufactured between the semiconductor substrate and the amorphous silicon interface, where it prevents silicon epitaxial growth between the crystalline silicon interface and the amorphous silicon interface. This architecture improves passivation, reduces parallel resistance, and enhances fill factor, leading to improved conversion efficiency of the solar cell.

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A method for passivating metal halide perovskite surfaces using an organic dye derivative that undergoes thermal conversion to form a stable dye. The dye is dissolved in a liquid and applied to the perovskite surface through spin-coating or drop-casting. The liquid and dye mixture undergoes thermal annealing to convert the dye derivative into a stable, fully dissolved dye that forms a protective layer on the perovskite surface. This approach enables the creation of stable perovskite solar cells through surface passivation without the need for conventional passivation agents.

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High-efficiency silicon heterojunction (HJT) solar cell design with a unique intrinsic passivation layer that improves conversion efficiency compared to conventional HJT cells. The cell has a thin SiO2 layer on the crystalline silicon substrate followed by a hydrogenated amorphous carbon silicon oxide (a-SiOx:H) layer. This a-SiOx:H layer provides excellent surface passivation and reduces interfacial recombination. It also has a modulated energy gap to balance absorption and transmission. The cell further uses optimized doping of the amorphous silicon layers near the substrate and TCO to prevent dopant diffusion into the a-SiOx:H layer and preserve its passivation effect.

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A partial tunnel oxide passivated contact structure for photovoltaic cells and modules that enables high-efficiency crystalline silicon solar cells through selective surface passivation. The structure features a tunnel oxide layer and polysilicon film applied only to the contact region, while maintaining conventional light absorption areas. This design suppresses recombination at metal contacts while preserving sunlight absorption, enabling improved efficiency and reduced costs.

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A crystalline silicon solar cell with improved efficiency, comprising a gallium oxide layer in direct contact with a P-type silicon layer, and a photovoltaic module incorporating the cell. The gallium oxide layer reduces minority carrier recombination, enhancing the cell's open-circuit voltage and short-circuit current. The module features a cover plate, encapsulant films, and a backplane, with the cell string comprising multiple cells connected by welding strips or conductive glue.

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A method for increasing stability and efficiency of organic perovskite materials in electronic devices, such as solar cells, by using a non-peripheral substituted phthalocyanine to passivate defects in the perovskite material. The phthalocyanine compound is added to the perovskite material during fabrication or coated onto its surface, and is believed to interact with under-coordinated lead ions to form a stable complex that reduces charge recombination and improves device performance.

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