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- 实验方案
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Three-Dimensional Laser-Assisted Patterning of Blue-Emissive Metal Halide Perovskite Nanocrystals inside a Glass with Switchable Photoluminescence
摘要： The high-precision patterning of metal halide perovskites (MHPs) is of paramount importance for their device application. Here, we demonstrate the femtosecond (fs)-laser-assisted formation of three-dimensional MHP nanocrystal (NC) patterns with strong blue photoluminescence (PL) inside an oxide glass. Our strategy enables the crystallization and erasing of CsPb(Cl/Br)3 NCs inside a glass localized around the laser focal area through a combination of fs laser irradiation and thermal treatment processes. These recoverable patterns exhibit a switchable PL associated with the laser-induced defect and the thermal healing of MHP NCs that are benefits from the soft ionic crystal structure and low formation energy of the MHPs. Due to the high stability offered by the protection of the oxide glass matrix, the laser printing of fine-structured MHP micropatterns can be repeated over multiple cycles with a high robustness compared with their colloidal process counterparts. Our results demonstrate a simple strategy for creating emissive patterns inside a stable and transparent solid matrix that could be promising for applications including information storage, three-dimensional displays, anticounterfeit labels, and information security protection.
关键词： three-dimensional patterning,perovskite nanocrystals,reversible photoluminescence,laser-assisted crystallization,femtosecond laser processing
更新于2025-09-16 10:30:52
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Study of Metala??Semiconductora??Metal CH3NH3PbBr3 Perovskite Photodetectors Prepared by Inverse Temperature Crystallization Method
摘要： Numerous studies have addressed the use of perovskite materials for fabricating a wide range of optoelectronic devices. This study employs the deposition of an electron transport layer of C60 and an Ag electrode on CH3NH3PbBr3 perovskite crystals to complete a photodetector structure, which exhibits a metal–semiconductor–metal (MSM) type structure. First, CH3NH3PbBr3 perovskite crystals were grown by inverse temperature crystallization (ITC) in a pre-heated circulator oven. This oven was able to supply uniform heat for facilitating the growth of high-quality and large-area crystals. Second, the di?erent growth temperatures for CH3NH3PbBr3 perovskite crystals were investigated. The electrical, optical, and morphological characteristics of the perovskite crystals were analyzed by X-ray di?raction (XRD), scanning electron microscopy (SEM), ultraviolet-visible spectroscopy, and photoluminescence (PL). Finally, the CH3NH3PbBr3 perovskite crystals were observed to form a contact with the Ag/C60 as the photodetector, which revealed a responsivity of 24.5 A/W.
关键词： inverse temperature crystallization,MSM photodetectors,CH3NH3PbBr3 perovskite crystals,large-area crystals
更新于2025-09-16 10:30:52
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Enhanced Nonlinear Optics Properties of a Bromine Chalcone from a novel Polymorph
摘要： This work presents crystallization, structural elucidation and a thorough study on nonlinear optical (NLO) properties calculated at DFT/CAM-B3LYP/6-311+G(d) level of a new bromine chalcone monoclinic polymorph (BRC-m). Both linear polarizability and second hyperpolarizability associated to NLO process of the intensity dependent refractive index (IDRI) were calculated. The dynamic third-order NLO susceptibility (χ(3)(―ω;ω,ω,―ω)) for BRC-m are higher than obtained experimentally for other chalcone derivatives. Furthermore, the theoretical results for BRC-m were compared with triclinic bromine chalcone (BRC-t); and the change of crystalline state (BRC-t to BRC-m) enhanced the third-order NLO susceptibility from 0.257 × 10―20m2/V2 to 2.48 × 10―20??2/??2 at 1064nm, respectively. This observation shows that future research on crystallization process of known NLO materials is a promising way to improve even more their potential optical application and improve the crystal quality.
关键词： structural elucidation,nonlinear optical properties,bromine chalcone,Crystallization,third-order susceptibility,monoclinic polymorph
更新于2025-09-16 10:30:52
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Chemical analysis of a lunar meteorite by laser ablation mass spectrometry
摘要： The lunar meteorite Sayh al Uhaymir 169, that contains KREEP rich material, was investigated with our miniature laser ablation time-of-flight mass spectrometer to simulate the expected performance of in-situ measurements on the surface of a planetary body. The abundances of the major elements on the KREEP part of the rock were measured and plotted on a two-dimensional surface map to identify different mineral phases in the sample. The element distribution maps reveal the grain boundaries and allow identification of individual minerals and their major and trace element compositions. In the second measurement campaign the instrument was coupled with a HV pulser to increase sensitivity of the measurements. It could be shown that the detection sensitivity for heavy trace elements can be significantly improved while removing light elements from the analyzed ion beam. This study provides also measurements of U, Th and Pb elements present inside a single zircon grain. With the abundances of U and Pb in the zircon grain a preliminary age estimation of the zircon could be made and was found to be in reasonable agreement with ages reported in literature. Moreover, from the Ti concentration in the zircon grain a crystallization temperature was derived. Thus, by employing such an instrument on a planetary surface, scientific useful in-situ measurements on the element composition, the mineralogy, petrology and dating of surface samples can be accomplished.
关键词： Lunar meteorite,Trace elements,Laser ablation mass spectrometry,Crystallization temperature,KREEP material,Zircon
更新于2025-09-12 10:27:22
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Crystallization Control of Ternary‐Cation Perovskite Absorber in Triple‐Mesoscopic Layer for Efficient Solar Cells
摘要： Controlling the crystallization of organic–inorganic hybrid perovskite is of vital importance to achieve high performing perovskite solar cells. The growth mechanism of perovskites has been intensively studied in devices with planar structures and traditional structures. However, for the printable mesoscopic perovskite solar cells, it is difficult to study the crystallization mechanism of perovskite owing to the complicated mesoporous structure. Here, a solvent evaporation controlled crystallization method to achieve ideal crystallization in the mesoscopic structure is provided. Combining results of scanning electron microscope and X-ray diffraction, it is found that adjusting the evaporation rate of solvent can control the crystallization rate of perovskite and a model for the crystallization process during annealing in mesoporous structures is proposed. Finally, a homogeneous pore filling in the mesoscopic structure without any additives is successfully achieved and a stabilized power conversion efficiency of 16.26% using ternary-cation perovskite absorber is realized. The findings will provide better understanding of perovskite crystallization in printable mesoscopic perovskite solar cells and pave the way for the commercialization of perovskite solar cells.
关键词： mesoscopic,perovskite solar cells,crystallization,solvent evaporation
更新于2025-09-12 10:27:22
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Efficient and stable tin-based perovskite solar cells by introducing π-conjugated Lewis base
摘要： Tin-based perovskite solar cells (TPSCs) as the most promising candidate for lead-free PSCs have incurred extensive researches all over the world. However, the crystallization process of tin-based perovskite is too fast during the solution-deposited process, resulting in abundant pinholes and poor homogeneity that cause serious charge recombination in perovskite layer. Here, we employed the π-conjugated Lewis base molecules with high electron density to systematically control the crystallization rate of FASnI3 perovskite by forming stable intermediate phase with the Sn-I frameworks, leading to a compact and uniform perovskite film with large increase in the carrier lifetime. Meanwhile, the introduction of the π-conjugated systems also retards the permeation of moisture into perovskite crystal, which significantly suppresses the film degradation in air. These benefits contributed to a stabilizing power conversion efficiency (PCE) of 10.1% for the TPSCs and maintained over 90% of its initial PCE after 1000-h light soaking in air. Also, a steady-state efficiency of 9.2% was certified at the accredited test center.
关键词： FASnI3 perovskite,π-conjugated Lewis base,perovskite solar cells,power conversion efficiency,crystallization rate
更新于2025-09-12 10:27:22
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Exploration of polymer-assisted crystallization kinetics in CsPbBr3 all-inorganic solar cell
摘要： All-inorganic perovskite material (CsPbBr3) has attracted enormous attention in photovoltaic devices due to superior stability. However, the thickness of CsPbBr3 film beyond 100 nm suffers from poor morphology, impurity phase and defects due to unbalance between fast growth and slow nucleation of film. Here, we introduce polyethylene glycol (PEG) into solution to achieve compact CsPbBr3 film with pure phase via a simple one-step solution process. The Lewis base of PEG interacts with the Lewis acid of Pb2+ to reduce the cluster size of CsBr-PbBr2-DMSO colloids as well as to increase the nucleation rate. The CsPbBr3 film magnitude less in intrinsic defect concentration is obtained by the addition of PEG. The open-circuit voltage increases from 1.15 eV to 1.41 eV with the highest efficiency of 7.8% as a result of less charge recombination of device, which is the highest efficiency ever recorded in one step solution process. The current–voltage curves measured at five different positions of large size device based on PEG (100 mm2) were almost identical, indicating highly uniform of devices. Thanks to the high quality of PEG modified CsPbBr3 film, there is no efficiency reduction during 120 h UV illumination. It was further used as a UV filter in tandem device which effectively restricts the UV degradation of bottom organic-inorganic perovskite solar cell. The tandem solar cell still remains 93% of the initial PCE after 120 h UV aging test, which are the main routes for commercializing device.
关键词： UV stability,CsPbBr3,Crystallization kinetics,Polyethylene glycol (PEG)
更新于2025-09-12 10:27:22
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Optimization of a precursor-PbI2 layer by re-crystallization for efficiency improvement in perovskite solar cells
摘要： Due to good light absorption capability, ease of production process and high potential of large area fabrication, perovskite solar cells receive a wide attention around the scientific community. Factors affecting the efficiency of perovskite solar cells include moisture, perovskite solution purity, completeness of perovskite layer and perovskite crystal grain size. In this work, the investigation of crystallization process of PbI2 as precursor for methyl ammonium lead triodide (CH3NH3PbI3) photo-absorber layer has been carried out. The inverted structure of FTO/PEDOT: PSS/CH3NH3PbI3/PCBM/Ag perovskite devices is fabricated using the two-step spin-coating method. The pre-heated PbI2 solution is left at room temperature to re-crystallize at various crystallization time (0-60 h). It was discovered that the perovskite solar cell using 48 h of crystallization time provides the highest power conversion efficiency of 9.69%. Morphology and crystallinity of perovskite layer will be discussed in relation to photovoltaic properties.
关键词： re-crystallization,perovskite solar cells,two-step spin - coating method,inverted structure
更新于2025-09-12 10:27:22
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Investigation of Crystallization Process of a Single Crystal Nickel-Based Alloy during the Laser Multilayer Cladding
摘要： The article shows the results of multilayer laser cladding of heat-resistant single crystal nickel-based alloy ZhS32-VI (CSMX-4 analogue). The influence of the main technological parameters on geometry and microstructure formation of deposited beads was investigated. Based on obtained dependencies, the regression equations are compiled for describing the shape of bead and the ratio of directional and equiaxial crystallized sections. The obtained dependencies of regime parameters nomination allow restoring the gas-turbine blades by the method of laser cladding.
关键词： gas-turbine blades,heat-resistant nickel-based alloys,laser cladding,crystallization,single crystal nickel-based alloys
更新于2025-09-12 10:27:22
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High-Performance Photodetector Based on Graphene Quantum Dot/CH3NH3PbI3 Perovskite Hybrid
摘要： Organometallic perovskites have great potential for their utilization in photodetector. However, the photoresponsivity of the perovskite film is limited by the low light absorption and charge transport capability. The preparation of good quality film with higher light–harvesting capability on the substrate has been a challenging job till now. In this work, we have developed high–quality white fluorescence graphene quantum dots and CH3NH3PbI3 hybrid film by one–step solvent–induced fast deposition–crystallization technique for the photodetector applications. Various amount of graphene quantum dots is added in composites to optimize the device performance and the hybrid film results in smooth and compactly distributed crystalline grains. The hybrid film device has exhibited 2 times higher photocurrent–to–dark current ratio, three–fold improved responsivity of 12 A W-1, detectivity enhancement upto 6.5 × 1011 Jones and a faster response speed compare to that of the neat MAPbI3 at -3 V bias voltage. The graphene quantum dots addition induces efficient charge transfer and enhances the photocurrent by more than 2 times compare to the neat film. High light absorption and fast charge transport capability of the film are the primary responsible for the high performance of the photodetector.
关键词： Photodetector,Graphene quantum dot,High–quality film,Fast deposition crystallization,CH3NH3PbI3 perovskite
更新于2025-09-12 10:27:22