- 标题
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Ethanol-Precipitable Silica-Passivated Perovskite Nanocrystals Incorporated into Polystyrene Microspheres for Long-Term Storage and Re-Usage
摘要： Perovskite nanocrystals (PNCs) are emerging luminescent materials due to their fascinating physic-optical properties. However, their sensitive surface chemistry with organic polar solvents, oxygen and moisture greatly hinders their developments towards practical applications. Herein we promote silica-passivated PNCs (SP-PNCs) by in situ hydrolyzing the surface ligands of (3-aminopropyl) triethoxysilane. The resultant SP-PNCs possesses a high quantum yield (QY) of 80% and are precipitable by polar solvents, such as ethanol and acetone, without destroying their surface chemistry or losing QY, which offers an eco-friendly and efficient method for separation, purification and phase transfer of PNCs compared with the traditional solvent evaporation technique. Moreover, we further promoted a swelling-deswelling encapsulation process to incorporate the as-made SP-PNCs into polystyrene microspheres (PMs), which can largely increase the stability of the SP-PNCs against moisture for long-term storage. Besides, the embedded SP-PNCs can also be reused and mono-dispersed by totally dissolving the PMs in suitable solvents for making all-solution-processed devices. We thereby believe this work should open new avenues for greener synthesis, scalable production, and long-term storage of PNCs towards the emerging practical applications.
关键词： stability,perovskite nanocrystals,surface engineering,encapsulation,polar environment
更新于2025-09-23 15:23:52
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Enhanced stability and optical absorption in the perovskite‐based compounds MA$_{1‐x}$Cs$_x$PbI$_{3‐y}$Br$_y$
摘要： Organometal halide perovskites have been outstanding from enormous amount of functional materials thanks to their highly cost-effective processability and prominent light harvesting capacity. Unfortunately, poor long-term stability seriously hinders their further development. The recent experimental observations suggest that Cesium is a promising candidate to enhance the stability of MAPbI3. To explore the inherent mechanism, a first-principles investigation based on density functional theory, including hybrid functional, has been performed to analyze the electronic and optical properties of perovskite series MA0.75Cs0.25PbI3-yBry. The results indicate that perovskite compound MA0.75Cs0.25PbI2Br is significantly superior to the other doped series in terms of optical absorption within the visible-light range. In the meanwhile, both Bader charge analysis and charge density distribution show that the compound of MA0.75Cs0.25PbI2Br is the most stable among all the doped perovskite series. Moreover, it is clearly manifested that the impact of cesium is mainly embodied in the enhancement of the stability rather than in the improvement of optical absorption. Our study sheds a new light on screening new-type light harvesting materials, and provides theoretical insight into the rationale design of highly efficient and stable photovoltaic devices based on these functional materials.
关键词： optical absorption,stability,first-principles calculations,perovskite compounds
更新于2025-09-23 15:23:52
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Light-illumination stability of amorphous InGaZnO thin film transistors in oxygen and moisture ambience
摘要： The light-illumination stability of amorphous InGaZnO Thin Film Transistors (a-IGZO TFTs) in oxygen and moisture ambience was in-depth characterized by both current-voltage (I-V) and capacitance-voltage (C-V) measurements. With the illuminated light wavelength decreasing, both I-V and C-V curves shifted negatively. When the ambient oxygen content or moisture level increased, the a-IGZO TFTs exhibited more stable properties under light illumination. A qualitative model was proposed to explain the related physical mechanism. The higher oxygen content or moisture level bene?ted the light-illumination-induced oxygen adsorption at back channels of a-IGZO TFTs and prevented the formation of oxygen vacancies (VO) in channel layers; the VO variation with the light illumination became more di?cult and hence led to better light-illumination stability of the corresponding TFT devices.
关键词： Thin ?lm transistor,Light-illumination stability,Amorphous InGaZnO,Ambient gases
更新于2025-09-23 15:23:52
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Stability and Spectral Properties of General Tree-Shaped Wave Networks with Variable Coefficients
摘要： The stability of general tree-shaped wave networks with variable coefficients under boundary feedback controls is considered. Making full use of the tree-shaped structures, we present a detailed asymptotic spectral analysis of the networks. By proposing the from-root-to-leaf calculating technique, we deduce an explicit recursive expression for the asymptotic characteristic equation and the spectral properties are further obtained. We show that the spectrum-determined-growth (SDG) condition holds. Thus the stability analysis of the closed-loop system can be completely converted to the infimum estimation of the asymptotic characteristic equation. Especially, we further show that the infimum is positive so as to obtain the exponential stability by estimating the recursive expression in from-leaf-to-root order. Some numerical simulations are presented to illustrate and support the theoretical results.
关键词： Exponential stability,Variable coefficient,Spectrum-determined-growth (SDG) condition,Recursive characteristic equation,Feedback control,Wave network
更新于2025-09-23 15:23:52
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Investigation of Structural and Elastic Stability, Electronic, Magnetic, Thermoelectric, Lattice-Dynamical and Thermodynamical Properties of Spin Gapless Semiconducting Heusler Alloy Zr2MnIn Using DFT Approach
摘要： In recent times, spin gapless semiconductors (SGS) have attracted much attention as a promising candidate for spintronics and thermoelectric applications due to their high carrier concentration and good thermoelectric figure of merit. In this paper, we have carried out a systematic theoretical investigation of the structural, elastic, thermal, electronic, magnetic, thermoelectric, lattice dynamical and thermodynamical properties of Zr2MnIn using density functional theory (DFT) based first principle calculations. The band structure calculation shows indirect band gap in a spin down channel and zero band gap in a spin up channel of valence and conduction bands confirming the spin gapless semiconducting nature of Zr2MnIn. The structural and dynamical stability of the antiferromagnetic phase of Zr2MnIn has also been investigated. Magnetization in Zr2MnIn originates due to the d state electrons of Zr atoms, which follows the Slater Pauling rule: Mt = Zt (cid:2) 18. Phonon dispersion curves exhibit real frequency of phonon modes throughout the Brillouin zone, which confirms the dynamical stability of the antiferromagnetic phase of Zr2MnIn. Thermodynamical properties including specific heat and Debye temperature have been calculated using phonon density of states. A higher value of the thermoelectric figure of merit 1.25, predicts that this alloy as good thermoelectric properties with better output efficiency.
关键词： Spin gapless semiconductor (SGS),magnetic moment,structural and elastic stability,thermoelectric and lattice dynamical properties,electronic structure
更新于2025-09-23 15:23:52
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Insertion of Nanoscale AgInSbTe Layer between the Ag Electrode and the CH <sub/>3</sub> NH <sub/>3</sub> PbI <sub/>3</sub> Electrolyte Layer Enabling Enhanced Multilevel Memory
摘要： Hybrid organic-inorganic perovskite, CH3NH3PbI3 (MAPbI3) has attracted great attention as promising building blocks for resistive switching memory. However, the reproductive switching uniformity and long-term environmental stability are always critical issues for practical application. Herein, by inserting nanoscale AgInSbTe (AIST) layer between the Ag electrode and MAPbI3 electrolyte layer (Ag/AIST/MAPbI3/FTO), the switching uniformity and environmental stability of the memory cell can be greatly improved. The suppression of excess Ag ions injection and the protection of MAPbI3 form air exposure with the help of AIST layer are ascribed to be responsible for the above-mentioned characteristics, respectively. Moreover, controllable tri-state switching in the reset process provided the capability of multilevel storage of the memory cells and the related mechanism has been identified as the control of nanoscale conductive filaments rupture in sequence from AIST to MAPbI3 layer. The present work would offer an effective way to develop high uniform and environmental stable MAPbI3-based high density memory systems.
关键词： AgInSbTe,stability,CH3NH3PbI3,uniformity,resistive switching
更新于2025-09-23 15:23:52
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Small HDL subclass is associated with coronary plaque stability: An optical coherence tomography study in patients with coronary artery disease
摘要： BACKGROUND: The role of high-density lipoprotein (HDL) subclasses in atherosclerotic diseases remains an open question. Previous clinical trials have attempted to explore the predictive effect of HDL subspecies on cardiovascular risk. However, no studies have assessed the connections between these subclasses and characteristics of plaque microstructure. OBJECTIVE: To investigate the relationship of HDL subclasses and coronary plaque stability assessed by optical coherence tomography (OCT). METHODS: Morphological characteristics of 160 nontarget lesions from 85 patients with coronary artery disease were assessed by OCT. HDL subclass profiles were analyzed using nondenaturing polyacrylamide gel electrophoresis. RESULTS: The plasma levels of small HDL subclass (percentage or concentration) were found to be positively associated with fibrous cap thickness (r = 0.232, P = .007; r = 0.243, P = .005) and negatively with maximum lipid arc (r = -0.240, P = .005; r = -0.252, P = .003) and lipid core length (r = -0.350, P < .001; r = -0.367, P < .001). Multivariate logistic regression analysis showed the small HDL subclass (percentage or concentration) (odds ratio [OR]: 0.457, 95% confidence interval [CI]: 0.214–0.974, P = .043; OR: 0.438, 95% CI: 0.204–0.938, P = .034) to be an independent factor in predicting OCT-detected thin-cap fibroatheroma of nontarget lesions. CONCLUSION: High levels of small HDL are associated with coronary nontarget plaque stability. Our findings suggest that the small HDL subtype might represent the atheroprotective activity of HDL.
关键词： Atherosclerosis,High-density lipoprotein,Optical coherence tomography,Plaque stability
更新于2025-09-23 15:23:52
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Structural, optical, and morphological stability of ZnO nano rods under shock wave loading conditions
摘要： Shock wave recovery experiment on crystalline materials is a hot research topic for aerospace applications. In this research article, authors present and demonstrate the stability of physical properties of ZnO nano rods (ZnO NRs) under shock wave loaded conditions. The test sample is synthesized by hydrothermal method and the shock waves were generated using a table top semi automatic pressure driven shock tube. A shock wave of 2.2 Mach number which has a transient pressure of 2.0 MPa and temperature 864 K was made to strike four test samples for the counts of 50,100,150 and 200, respectively. The shock loaded samples were subjected to XRD and optical analysis so as to understand the influence of shock waves in the structural and optical properties. The results show that ZnO NRs have magnificent molecular, optical, structural and morphological stability for 50,100 and 150 shocks. Though, when the number of shock pulses was increased to 200 and a blue shift was observed in UV-Vis spectrum, no changes in structural properties took place which was evidenced from XRD. From this shock wave recovery experiment, it is clear that ZnO NRs are highly stable against shock waves and hence this material is suggested for the aerospace and military applications.
关键词： ZnO nano rods,Aerospace applications,Structure stability,Shock waves
更新于2025-09-23 15:23:52
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Thermally-stable large strain in Bi(Mn0.5Ti0.5)O3 modified 0.8Bi0.5Na0.5TiO3-0.2Bi0.5K0.5TiO3 ceramics
摘要： A N U S C RIP T (1-x)[0.8Bi0.5Na0.5TiO3-0.2Bi0.5K0.5TiO3]-xBi(Mn0.5Ti0.5)O3 (x = 0 ~ 0.06, BNKMT100x) lead-free ferroelectric ceramics were prepared via solid state reaction method. Bi(Mn0.5Ti0.5)O3 induces a structure transition from rhombohedral-tetragonal morphotropic phases to pseudo-cubic phase. Moreover, the wide range of compositions within x = 0.03 ~ 0.055 exhibit large strain of 0.31% ~ 0.41% and electrostrictive coefficient of 0.027 ~ 0.041 m4/C2. Especially, at x = 0.04, the large strain and electrostrictive coefficient are nearly temperature-independent in the range of 25 ~ 100 °C. The impedance analysis shows the large strain and electrostrictive coefficient originate from polar nanoregions response due to the addition of Bi(Mn0.5Ti0.5)O3.
关键词： large strain,thermal stability,composition-insensitivity,lead-free,electric property
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Energy Conversion Congress and Exposition (ECCE) - Portland, OR, USA (2018.9.23-2018.9.27)] 2018 IEEE Energy Conversion Congress and Exposition (ECCE) - Current-Fed Quasi Z-Source Inverter Based PV Distributed Generation Controller
摘要： Recently, the renewable photovoltaic distributed generation (PV-DG) enjoys a rapid growth globally due to the advancement in solar systems and power electronics technologies. However, the intermittent nature of solar radiation and performance of the attached power converters, inevitably poses some challenges to the power grids integrated large-scale solar-farms (SF). These challenges include frequency oscillations, voltage variation and power quality issues. To overcome these problems, this study proposes a Current-Fed quasi Z-source Inverter (CF-qZSI) as an alternative converter for distribution generation controllers to facilitate the integration of a PV energy source into a weak power system. The detailed model of the CF-qZSI-based distribution controller (CqZDC) and its control system are developed. The dynamic performance of the CqZDC device is evaluated to validate different objectives using an actual field data and RTDS simulation platform.
关键词： frequency stability,current source inverter,wide band gap devices,Accommodation of renewable energy resources,power quality improving,facilitating of distributed electricity generations
更新于2025-09-23 15:23:52