- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Post-synthesis phase and shape evolution of CsPbBr3 colloidal nanocrystals: The role of ligands
摘要： The surface chemistry of colloidal cesium lead bromide (CsPbBr3) nanocrystals is decisive in determining the stability and the final morphology of this class of materials, characterized by ionic structure and a high defect tolerance factor. Here, the high sensitivity of purified colloidal nanocubes of CsPbBr3 to diverse environmental condition (solvent dilution, ageing, ligands post synthetic treatment) in ambient atmosphere is investigated by means of a comprehensive morphological (electron microscopy), structural (θ/2θ X-ray diffraction (XRD) and grazing incidence wide angle scattering (GIWAXS)), and spectroscopic chemical (1H nuclear magnetic resonance (NMR), nuclear Overhauser effect spectroscopy (NOESY), absorption and emission spectroscopy) characterization. The aging and solvent dilution contribute to modify the nanocrystal morphology, due to a modification of the ligand dynamic. Moreover, we establish the ability of aliphatic carboxylic acids and alkyl amines ligands to induce, even in a post preparative process at room temperature, structural, morphological and spectroscopic variations. Upon post synthesis alkyl amine addition, in particular of oleyl amine and octyl amine, the highly green emitting CsPbBr3 nanocubes effectively turn into one-dimensional (1D) thin tetragonal nanowires or lead halide deficient rhombohedral zero-dimensional (0D) Cs4PbBr6 structures with a complete loss of fluorescence. The addition of an alkyl carboxylic acid, as oleic and nonanoic acid, produces the transformation of nanocubes into still emitting orthorombic two-dimensional (2D) nanoplates. The acid/base equilibrium between the native and added ligands, the adsorbed/free ligands dynamic in solution and the ligand solubility in non-polar solvent contribute to render CsPbBr3 particularly sensitive to environmental and processing conditions and, therefore prone to undergo to structural, morphological and, hence spectroscopic, transformations.
关键词： lead halide perovskite nanocrystals,surface chemistry,ligands equilibria,long term stability
更新于2025-11-21 11:01:37
-
Direct synthesis of ultrasmall and stable magnetite nanoparticles coated with one single carbon layer for sensitive surface-enhanced Raman scattering
摘要： Ultrasmall spherical magnetite nanoparticles (Fe3O4 NPs) coated with one single carbon layer (Fe3O4@1C NPs) were directly synthesized by a simple, fast one-step hydrothermal reaction at low temperature (200℃). The as-synthesized Fe3O4@1C NPs were easily separated and purified from the resultant mixture, without the need for any additional energy input and chemicals. The as-purified Fe3O4@1C NPs not only displayed typical superparamagnetic behavior but also exhibited quite good long-term stability after being exposed to the open air under the room conditions for more than 2 months. Importantly, the long-term stored Fe3O4@1C NPs exhibited a highly sensitive surface-enhanced Raman spectroscopy (SERS) response toward Rhodamine-b (RdB) molecules with low concentration. The multifunctional and recyclable Fe3O4@1C NPs presented a prospective application for the selective enrichment and sensitive SERS detection of chemical and biomolecular assays.
关键词： coated with one single carbon layer (Fe3O4@1C NPs),Dehydration reaction,Saturation magnetization,Long-term stability,Magnetite nanoparticles (Fe3O4 NPs)
更新于2025-11-14 17:03:37
-
Hybrid Laser Ablation and Chemical Modification for Fast Fabrication of Bio-inspired Super-hydrophobic Surface with Excellent Self-cleaning, Stability and Corrosion Resistance
摘要： Although laser ablation is considered as a facile technique to fabricate bio-inspired super-hydrophobic surfaces, the issue is that the initial laser treated metallic surfaces show super-hydrophilic property. It will take a long period to reach super-hydrophobic state under ambient air. It is reported that these super-hydrophobic surfaces could be easily damaged by thermal heating effect or interaction with other liquids, causing uncontrolled loss of super-hydrophobicity. In this study, a stable super-hydrophobic aluminum surface was rapidly fabricated via the hybrid laser ablation and surface chemical modification of (heptadecafluoro-1, 1, 2, 2-tetradecyl) triethoxysilane (AC-FAS). Surface morphology and chemistry were systematically investigated to explore the generation mechanism of super-hydrophobicity. The water contact angle of the treated surfaces can reach up to 160.6? ± 1.5? with rolling angle of 3.0? ± 1.0?, exhibiting perfect self-cleaning capability, long-term stability, and excellent chemical stability in acidic as well as alkaline solutions. The potentiodynamic polarization tests implied that the super-hydrophobic surfaces showed better anti-corrosion performance. This hybrid laser ablation and surface chemical modification are very time-saving and low-cost, which offers a rapid way for quantity production of super-hydrophobic surface on aluminum material.
关键词： nanosecond laser,bioinspiration,corrosion resistance,chemical stability,self-cleaning,super-hydrophobic,long-term stability
更新于2025-09-23 15:22:29
-
From Aggregates to Porous Three-Dimensional Scaffolds through a Mechanochemical Approach to Design Photosensitive Chitosan Derivatives
摘要： The crustacean processing industry produces large quantities of waste by-products (up to 70%). Such wastes could be used as raw materials for producing chitosan, a polysaccharide with a unique set of biochemical properties. However, the preparation methods and the long-term stability of chitosan-based products limit their application in biomedicine. In this study, different scale structures, such as aggregates, photo-crosslinked films, and 3D scaffolds based on mechanochemically-modified chitosan derivatives, were successfully formed. Dynamic light scattering revealed that aggregation of chitosan derivatives becomes more pronounced with an increase in the number of hydrophobic substituents. Although the results of the mechanical testing revealed that the plasticity of photo-crosslinked films was 5–8% higher than that for the initial chitosan films, their tensile strength remained unchanged. Different types of polymer scaffolds, such as flexible and porous ones, were developed by laser stereolithography. In vivo studies of the formed structures showed no dystrophic and necrobiotic changes, which proves their biocompatibility. Moreover, the wavelet analysis was used to show that the areas of chitosan film degradation were periodic. Comparing the results of the wavelet analysis and X-ray diffraction data, we have concluded that degradation occurs within less ordered amorphous regions in the polymer bulk.
关键词： laser stereolithography,mechanochemical synthesis,long-term stability,tissue reaction,chitosan,scaffold
更新于2025-09-23 15:22:29
-
An Intera??Laboratory Study on the Stability of Alla??Printable HTMa??Free Perovskite Solar Cells
摘要： Comparison between different laboratories on long-term stability analyses of perovskite solar cells (PSCs) is still lacking in the literature. This work presents the results of an inter-laboratory study carried out between 5 laboratories from 4 countries. Carbon-based PSCs were prepared by screen printing, encapsulated and sent to different laboratories across Europe to assess their stability by the application of three ISOS aging protocols: (a) in the dark (ISOS-D), (b) under simulated sunlight (ISOS-L) and (c) outdoors (ISOS-O). Over 1000 hours stability is reported for devices in the dark, both at room temperature and at 65 °C. Under continuous illumination at open circuit, cells survived only for few hours, although they recovered after being stored in the dark. Better stability is observed for cells biased at maximum power point under illumination. Finally, devices operate in outdoors for 30 days, with minor degradation, in two different locations (Barcelona, Spain and Paola, Malta). Our findings demonstrate that open circuit conditions are too severe for stability assessment and that the diurnal variation of the PV parameters reveals performance to be strongly limited by the fill factor, in the central hours of the day, due to the high series resistance of the carbon electrode.
关键词： carbon,perovskite solar cells,long-term stability,inter-laboratory study,ISOS protocols
更新于2025-09-23 15:21:01
-
Shallow and Deep Trap States Passivation for Low-Temperature Processed Perovskite Solar Cells
摘要： While perovskite solar cells (PSCs) have emerged as promising low-cost solar power generators, most reported high-performance PSCs employ electron transport layers (ETLs, mainly TiO2) treated at high temperatures (≥450 °C), which may eventually hinder the development of flexible PSCs. Meanwhile, the development of low-temperature processed PSCs (L-PSCs) possessing performance levels comparable to that of high-temperature processed PSCs has actively been reported. In this study, L-PSCs with improved long-term stability and negligible hysteresis were developed through the effective passivation of shallow and deep traps in organic-inorganic hybrid perovskite (OIHP) crystals and at the ETL/OIHP interface. L-PSCs with alkaline chloride modification achieved state-of-the-art performance among reported L-PSCs (power conversion efficiency (PCE) = 22.6%) with a long-term shelf life. The origin of long-term stability and the efficient passivation of deep traps was revealed by monitoring the trap-state distribution. Moreover, the high PCE of a large-area device (21.3%, 1.12 cm2) were also demonstrated, confirming the uniformity of the modification.
关键词： trap states passivation,low-temperature processed,alkaline chloride modification,perovskite solar cells,long-term stability
更新于2025-09-23 15:21:01
-
One-step Co-evaporation of All-Inorganic Perovskite Thin Films with Room Temperature Ultralow Amplified Spontaneous Emission Threshold and Air-stability
摘要： Inorganic cesium lead halide perovskite has been successfully applied in optoelectronic field due to its remarkable optical gain properties. Unfortunately, conventional solution-processed CsPbX3 films suffer unavoidable pinhole defects and poor surface morphology, severely limiting their performance on amplified spontaneous emission (ASE) and lasing application. Herein, a dual-source thermal evaporation approach is explored in our work to achieve a uniform and high-coverage CsPbX3 polycrystalline thin film. It is found that the one-step co-evaporated CsPbBr3 (OC-CsPbBr3) thin films without post-annealing exhibit an ultralow ASE threshold of ~ 3.3 μJ/cm2 and gain coefficient above 300 cm-1. The coexistence of cubic and orthorhombic phases in this materials naturally form an energy cascade for the exciton transfer process, which enables rapid accumulation of excitons. Stable ASE intensity without degradation for at least 7 hours is also realized from OC-CsPbBr3 thin films under continuous excitation, which is superior to that in the solution-processed CsPbBr3 thin film. Notably, a Fabry-Perot (F-P) cavity laser based on the OC-CsPbBr3 thin film is first achieved, featuring an ultralow lasing threshold (1.7 μJ/cm2) and directional output (beam divergence of ~ 3.8°). This work highlights the noteworthy optical properties of OC-CsPbBr3 thin films, leading to potential available applications in the integrated optoelectronic chips.
关键词： amplified spontaneous emission,Cesium lead halide perovskite,vapor deposition,long-term stability,thin films
更新于2025-09-23 15:21:01
-
Narrow Bandpass and Efficient Semitransparent Organic Solar Cells Based on Bioinspired Spectrally Selective Electrodes
摘要： The visual aesthetic that involves color, brightness, and glossiness is of great importance for building-integrated photovoltaics. Semi-transparent organic solar cells (ST-OSCs) are thus considered as the most promising candidate due to their superiority in transparency and efficiency. However, the realization of high color purity with narrow bandpass transmitted light usually causes the severely suppressed transparency in ST-OSCs. Herein, we present a spectrally selective electrode (SSE) by imitating the integrating strategy of beetle cuticle for achieving narrow bandpass ST-OSCs with high efficiency and long-term stability. The proposed SSE allows for efficient light-selective passage, leading to tunable narrow bandpass transmitted light from violet to red. An optimized power conversion efficiency of 15.07% is achieved for colorful ST-OSCs, which exhibit color purity close to 100% and a peak transmittance approaching 30%. Long-term stability is also improved for ST-OSCs made with this SSE due to the light-rejecting and the moisture-blocking abilities. The realization of bright and colorful ST-OSCs also indicates the application potential of SSEs in light-emitting diodes, lasers, and photodetectors.
关键词： beetle cuticle,visual aesthetic,color purity,semi-transparent organic solar cells,long-term stability
更新于2025-09-23 15:21:01
-
Polymer Controlled Growth and Wrapping of Perovskite Single Crystals Leading to Better Device Stability and Performance
摘要： Commodity scale polymer is used for controlling the nucleation and growth of single crystals of organolead halide perovskite. The polymer (polystyrene (PS)) cross-links and strongly interact with PbI2 and MAI (MAPbI3 perovskite precursors) resulting in the control of the crystallization process. The PS concentration modulates the nucleation time, crystal size and the number of perovskite single crystals. In addition, the PS based MAPbI3 crystals show an enhanced performance as well as improved thermal and environmental stability. Specifically, the PS-MAPbI3 crystals show 3 times higher photocurrent than plain MAPbI3 crystals and maintains a stable structure for more than 50 days (1200 h) under continuous 0.1 sun illumination in the air with a relative humidity of 40–45%. The improved performance and stability are attributed to the direct interaction between the PS and perovskite, which greatly reduces the ion migration, defect traps and charge recombination, and improves the carrier mobility and lifetime.
关键词： ion migration effect,photocurrent,perovskite,long-term stability,optoelectronics,crystal growth
更新于2025-09-23 15:21:01
-
Bilateral Interface Engineering for Efficient and Stable Perovskite Solar Cells using Phenylethylammonium Iodide
摘要： Achieving high efficiency and long-term device stability is a vital issue for the commercialization of organic-inorganic hybrid perovskite solar cells (PeSCs). In this work, phenyl ethyl-ammonium iodide (PEAI)-induced bilateral interface engineering was developed to improve the device efficiency and stability of methylammonium lead triiodide (MAPbI3)-based PeSCs. Introducing PEAI onto poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) layer modifies the surface properties of the PEDOT:PSS and facilitates the formation of a high-quality perovskite active layer with enlarged grains on the PEDOT:PSS. The PEA+ in the PEAI-PEDOT:PSS also alters the work function of the PEDOT:PSS, leading to a reduction in the energy difference between the PEDOT:PSS and MAPbI3 perovskite layer, which decreases energy loss during charge transfer. Additionally, depositing PEAI onto three dimensional (3D) perovskite yields a two dimensional/three dimensional (2D/3D) stacked structure for the perovskite active layer. Because the two dimensional (2D) top layer acts as a capping layer to prevent water penetration, the stability of the perovskite active layer is significantly enhanced. A PeSC device fabricated based on this combination exhibits enhanced power conversion efficiency and extended device lifetime compared to a pristine PeSC. Under high-humidity conditions (75 ± 5%), the PEAI-treated PeSC retains 88% of its initial power conversion efficiency (PCE) after 100 h. In contrast, a pristine PeSC device loses over 99% of its initial PCE after only 25 h under the same conditions.
关键词： high efficiency,perovskite solar cells,bilateral interface engineering,PEAI,long-term stability
更新于2025-09-23 15:21:01