Surface Passivation Methods for Quantum Dot Solar Cells

Heterojunction PbS quantum dot solar cell with enhanced light absorption and charge collection through nanostructured PN junction layers. The cell features a stacked glass substrate with a nano-patterned PbS quantum dot layer, followed by a PN junction layer with ZnO nanoparticles as optical antennas. The ZnO nanoparticles serve as efficient light-harvesting materials while maintaining electronic inertness, enabling improved charge collection and filling factor. The nanostructured architecture enables efficient light absorption and carrier transport through the PbS quantum dot layer, while the PN junction layer enhances charge collection at the contact interface.

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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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A solar cell with improved absorption efficiency and reduced stress resistance through optimized passivation layer design. The design incorporates a specific sequence of passivation layers with different refractive indices, where the second layer has a higher refractive index than the third layer. This arrangement enables selective absorption of light across the solar spectrum while minimizing internal reflection and field passivation effects. The second layer, comprising silicon nitride with a specific atomic ratio, provides enhanced absorption properties, while the third layer, comprising silicon oxynitride, enhances the refractive index of the solar cell. The sequence of layers is carefully controlled to balance absorption efficiency with structural integrity and cost considerations.

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A two-step passivation method for solid state quantum devices like quantum dot lasers that improves their optical quality and longevity by effectively removing surface states. The method involves depositing a sulfide layer followed by an oxide layer. First, the devices are pretreated in acid to remove native oxide. Then, they are placed in a hydrogen sulfide-filled chamber with ultraviolet light to displace oxide with sulfur atoms. This forms a compact sulfide layer. Next, the devices are transferred to an atomic layer deposition chamber to deposit a thin oxide layer on top. This completes the passivation process. The sulfide layer reduces surface states, while the oxide isolates the device from air to prevent oxidation.

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Solar cell design with patterned passivation and carrier transmission layers to improve efficiency by reducing interface recombination and allowing efficient charge extraction. The solar cell has light absorption layer with alternating patterned passivation and carrier transmission layers on some of its surfaces. This allows selective passivation of defects at interfaces without blocking charge extraction. The patterned design reduces interface recombination compared to full passivation and improves fill factor and voltage compared to no passivation.

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Surface treatment method for quantum dots that enables reliable and stable quantum dot synthesis through controlled photopolymerization of reactive surface ligands. The method involves supplying quantum dots and reactive ligand solutions through a controlled flow system while irradiating them with a specific light source. The photopolymerization process enables uniform coverage of the quantum dot surface, preventing incomplete coverage and degradation of the quantum dot material.

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Lead sulfide quantum dot/polymer hybrid solar cells that achieve high efficiency through controlled interface engineering. The hybrid cells incorporate an interface layer with thiol ligands between the lead sulfide quantum dots and polymer matrix, which enhances charge transport and optoelectronic properties. The interface layer selectively passesivates the quantum dot/polymer interface, reducing energy band bending and charge accumulation, while maintaining the quantum dot's photovoltaic properties. This approach enables near-infrared photovoltaic devices with improved charge transport characteristics compared to conventional lead sulfide solar cells.

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A solar cell that achieves high open-circuit voltage (VOC) and short-circuit current (JSC) through the integration of quantum dots with different bandgaps in a solution-processed semiconductor matrix. The matrix enables the formation of a composite film with optimized optical absorption properties, specifically tailored to the infrared spectrum. By engineering the density of states in the quantum dots, the matrix achieves improved quasi-Fermi level splitting and increased VOC, while maintaining charge transport properties. This approach enables the realization of solar cells with significantly higher VOC and JSC than conventional Si-based solar cells, approaching the theoretical limit of 6% power conversion efficiency.

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A method for preparing a metal oxide-coated quantum dot and dye co-sensitized solar cell through a single-step process. The method involves converting bulk quantum dots into water-soluble quantum dots through ligand exchange, followed by a hydrothermal reaction to form a thin metal oxide layer on the quantum dots. The resulting quantum dot@metal oxide composite is then coated with a metal oxide layer through annealing, followed by dye deposition. This integrated approach enables the creation of high-efficiency solar cells by combining the benefits of quantum dots as sensitizers with metal oxide electron transport layers.

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Quantum dot particles with enhanced protection against environmental degradation. The particles feature a dual-layer passivation system where the first layer provides moisture barrier protection during deposition, while the second layer offers enhanced surface protection. The first layer is formed prior to deposition and is specifically designed to prevent water contact, while the second layer is deposited on top of the first layer. This dual-layer approach enables effective moisture protection while maintaining sufficient surface coverage for effective quantum dot particle protection.

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Solar cell with enhanced surface passivation through a novel dual-layer approach. The cell features a substrate with two sequential passivation layers: a chemical passivation layer on the surface and a field passivation layer above it. The field passivation layer contains a zwitterionic compound that forms an anionic group at its surface, creating a localized negative charge. This anionic group interacts with the surface defects, reducing carrier recombination and carrier concentration. The chemical passivation layer provides a broader surface coverage, while the field passivation layer enhances the local field effect. The combined dual-layer architecture enables improved surface passivation, leading to enhanced solar cell performance.

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A method for enhancing the efficiency of solar cells by using a layer-by-layer self-assembly ZnSe/ZnS core-shell structure with quantum dots. The method involves depositing ZnSe/ZnS quantum dots with negative surface charge and ZnSe/ZnS quantum dots with positive surface charge through a spin-coating process at low speeds. These core-shell structures are then assembled through layer-by-layer self-assembly to form a fluorescence down transfer layer. The core-shell structure enables efficient transfer of energy from ultraviolet photons to the solar cell's p-n junction, thereby improving spectral response and overall efficiency.

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Preparing a quantum dot-sensitized solar cell with ultra-thin PMMA passivation layer through a novel method that enables both passivation and charge management simultaneously. The process involves depositing a ultra-thin PMMA layer as the passivation interface, which not only prevents interface defects but also suppresses charge recombination. This dual-function approach enables improved charge extraction and collection while maintaining the structural integrity of the passivation layer. The ultra-thin PMMA layer can be deposited using conventional techniques, such as spin coating or evaporation, and is compatible with the quantum dot-sensitized solar cell architecture.

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Quantum dot solar cells with enhanced carrier recombination inhibition through a novel nitride semiconductor layer. The layer, comprising a wide band gap material such as ZnS, Al2O3, or MgO, is deposited on the surface of quantum dots to prevent carrier recombination at the interface. This layer achieves precise control over thickness, allowing precise carrier transport while maintaining optimal contact with the TiO2 surface. The nitride layer enables efficient hole transport while minimizing carrier recombination, resulting in improved solar cell efficiency.

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All-solid-state solar cells based on simultaneous deposition of quantum dots and a novel preparation method achieve high efficiency, low cost, and stability through a novel device architecture. The solar cells employ quantum dots as light-absorbing materials, which are deposited simultaneously with the photovoltaic layer through a novel deposition process. This approach eliminates the need for organic solvents and high-temperature processing, while maintaining the quantum dot's inherent properties. The device architecture enables efficient charge carrier collection and transport, resulting in improved photovoltaic performance compared to conventional quantum dot solar cells.

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CsPbBr3 quantum dot-silicon composite solar cell that improves efficiency by adding a thin layer of CsPbBr3 quantum dots on the silicon chip. The quantum dots absorb short-wavelength UV light that silicon can't and convert it to visible light that silicon can absorb. This reduces reflection, increases short-circuit current, and external quantum efficiency at short wavelengths. The CsPbBr3 quantum dot film is spin-coated with thickness 20-50nm.

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A method for preparing high-performance quantum dots for solar cells that overcomes the limitations of conventional quantum dot-metal oxide interfaces. The method involves modifying oil-soluble quantum dots with silane coupling agents to create surface-modified quantum dots, followed by a cross-linking reaction with fullerol to form stable nanoparticles. These modified quantum dots exhibit enhanced charge transfer properties compared to conventional interfaces, enabling efficient charge collection in solar cells.

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Preparation of photoanode for co-sensitized quantum dot solar cells through the synthesis of Zn-Cu-In-Se (ZCISe) quantum dots. The synthesis of ZCISe quantum dots involves the controlled synthesis of Zn-Cu-In-Se nanocrystals in water, followed by their subsequent conversion to oil-soluble form. This enables the preparation of water-soluble ZCISe quantum dots that can be used to create co-sensitized photoanodes for quantum dot solar cells. The photoanode is then assembled by combining the ZCISe quantum dots with CdSe quantum dots, resulting in a co-sensitized photoanode that achieves high photocurrent and photoelectric conversion efficiency.

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A method for preparing CdSeTe quantum dot sensitized solar cells with enhanced surface passivation properties. The method involves preparing a Se source solution by magnetic stirring of Se powder in liquid paraffin at 100°C, followed by controlled cooling to form a transparent and colorless solution. The Cd source solution is prepared by stirring CdC12 · 2.5H2O powder in liquid paraffin, with the stirring process controlled to prevent agglomeration. The Se source solution is then used to prepare CdSeTe quantum dots, which are then sensitized with the Se source solution to form sensitized quantum dots. The sensitized quantum dots are then sensitized with the Cd source solution to form sensitized solar cells with improved surface passivation properties.

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Solar cells with enhanced spectral response through the use of ZnSe/ZnS colloidal quantum dots. The solar cells incorporate ZnSe/ZnS colloidal quantum dots with negatively charged groups, which form a core-shell structure through surface electrostatic interaction. The ZnSe/ZnS colloidal quantum dots enable efficient conversion of ultraviolet (UV) photons into visible light, significantly improving the solar cell's spectral response beyond the traditional Si-based solar cells.

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