Application of monodisperse TiO2 nanoparticles with the size of 8–10 nm in dye-sensitized solar cells

In this paper, the commercial monodisperse TiO₂ nanoparticles with the size of 8–10 nm were successfully applied to the photoelectrode for dye-sensitized solar cells (DSCs) and the influence of the thickness of the TiO₂ thin films on the photovoltaic performance of the DSCs was investigated. The result revealed that the DSCs with the TiO₂ thin film thickness of 3.6, 8.0, 11.6 and 20.0 μm gave the photoelectric conversion efficiency of 3.67%, 5.92%, 6.71% and 7.03%, respectively, under the illumination of simulated AM 1.5 sunlight (100 mW cm⁻²).     

Circular patterns of calcium oxalate crystals induced by defective Langmuir-Blodgett film

The injury of the renal epithelial cell membrane can promote the nucleation of nascent crystals, as well as adhesion of crystals on it. It thus accelerates the formation of renal calculi. In this paper, the defective Langmuir-Blodgett (LB) films were used as a model system to simulate the injured renal epithelial cell membrane. The microcosmic structure of the defective LB film and the molecular mechanism of the effect of this film on nucleation, growth, deposited patterns and adhesion of calcium oxalate monohydrate (COM) were investigated. The circular defective domains were formed in dipalmitoylphosphatidylcholine (DPPC) LB film after the film was treated by potassium oxalate. These domains could induce ring-shaped patterns of COM crystals. In comparison, the LB film without pretreatment by potassium oxalate only induced random growth of hexagonal COM crystals. As the crystallization time increased, the size of COM crystals in the patterns increased, the crystal patterns changed from empty circles to solid circles, and the number of the circular patterns with small size (5-20 μm) increased. The results would shed light on the molecular mechanism of urolithiasis induced by injury of the renal epithelial membrane at the molecular and supramolecular level.     

Nitrogen Plasma Enhanced Low Temperature Atomic Layer Deposition of Magnesium Phosphorus Oxynitride (MgPON) Solid-State Electrolytes

Solid-state batteries (SSBs) that use solid electrolytes instead of flammable liquid electrolytes have the potential to generate higher specific capacity and offer better safety. Magnesium (Mg) based SSBs with Mg metal anodes are considered to be one of the most promising energy storage candidates, because it gives high theoretical volumetric capacities of 3830 mAh cm⁻³. Here, we demonstrate an atomic layer deposition (ALD) process with a double nitrogen plasma process that successfully produces nitrogen-incorporated magnesium phosphorus oxynitride (MgPON) solid-state electrolyte (SSE) thin films at a low deposition temperature of 125 °C. The ALD MgPON SSEs exhibit an ionic conductivity of 0.36 and 1.2 μS cm⁻¹ at 450 and 500 °C, respectively. The proposed ALD strategy shows the ability of conformal deposition nitrogen-doped SSEs on pattered substrates and is attractive for using nitride ion-conducing films as protective or wetting interlayers in solid-state Mg and Li batteries.     

Carboxysome-Inspired Electrocatalysis using Enzymes for the Reduction of CO2 at Low Concentrations**

The electrolysis of dilute CO₂ streams suffers from low concentrations of dissolved substrate and its rapid depletion at the electrolyte-electrocatalyst interface. These limitations require first energy-intensive CO₂ capture and concentration, before electrolyzers can achieve acceptable performances. For direct electrocatalytic CO₂ reduction from low-concentration sources, we introduce a strategy that mimics the carboxysome in cyanobacteria by utilizing microcompartments with nanoconfined enzymes in a porous electrode. A carbonic anhydrase accelerates CO₂ hydration kinetics and minimizes substrate depletion by making all dissolved carbon available for utilization, while a highly efficient formate dehydrogenase reduces CO₂ cleanly to formate; down to even atmospheric concentrations of CO₂. This bio-inspired concept demonstrates that the carboxysome provides a viable blueprint for the reduction of low-concentration CO₂ streams to chemicals by using all forms of dissolved carbon.     

Balancing the Crystallinity and Film Formation of Metal–Organic Framework Membranes through In Situ Modulation for Efficient Gas Separation

Polycrystalline metal–organic framework (MOF) layers hold great promise as molecular sieve membranes for efficient gas separation. Nevertheless, the high crystallinity tends to cause inter-crystalline defects/cracks in the nearby crystals, which makes crystalline porous materials face a great challenge in the fabrication of defect-free membranes. Herein, for the first time, we demonstrate the balance between crystallinity and film formation of MOF membrane through a facile in situ modulation strategy. Monocarboxylic acid was introduced as a modulator to regulate the crystallinity via competitive complexation and thus concomitantly control the film-forming state during membrane growth. Through adjusting the ratio of modulator acid/linker acid, an appropriate balance between this structural “trade-off” was achieved. The resulting MOF membrane with moderate crystallinity and coherent morphology exhibits molecular sieving for H₂/CO₂ separation with selectivity up to 82.5.     

Foam films stabilized with alpha olefin sulfonate (AOS)

Alpha olefin sulfonate (AOS) surfactants have shown outstanding detergency, lower adsorption on porous rocks, high compatibility with hard water and good wetting and foaming properties. These properties make AOS an excellent candidate for foam applications in enhanced oil recovery. This paper summarizes the basic properties of foam films stabilized by an AOS surfactant. The foam film thickness and contact angle between the film and its meniscus were measured as a function of NaCl and AOS concentrations. The critical AOS concentration for formation of stable films was obtained. The critical NaCl concentration for formation of stable Newton black films was found. The dependence of the film thickness on the NaCl concentration was compared to the same dependence of the contact angle experiments. With increasing NaCl concentration the film thickness decreases gradually while the contact angle (and, respectively the free energy of film formation) increases, in accordance with the classical DLVO theory.The surface tension isotherms of the AOS solutions were measured at different NaCl concentrations. They coincide on a single curve when plotted as a function of mean ionic activity product. Our data imply that the adsorption of AOS is independent of NaCl concentration at a given mean ionic activity.     

Efficient Visible-Light-Activated Ultra-Long Room-Temperature Phosphorescence Triggered by Multi-Esterification

The development of ultra-long room-temperature phosphorescence (UL-RTP) in processable amorphous organic materials is highly desirable for applications in flexible displays, anti-counterfeiting, and bio-imaging. However, achieving efficient UL-RTP from amorphous materials remains a challenging task, especially with activation by visible light and a bright afterglow. Here we report a general and rational molecular-design strategy to enable efficient visible-light-excited UL-RTP by multi-esterification of a rigid large-plane phosphorescence core. Notably, multi-esterification minimizes the aggregation-induced quenching and accomplishes a ′four birds with one stone′ possibility in the generation and radiation process of UL-RTP: i) shifting the excitation from ultraviolet light to blue-light through enhancing the transition dipole moment of low-lying singlet-states, ii) facilitating the intersystem crossing process through the incorporation of lone-pair electrons, iii) boosting the decay process of long-lived triplet excitons resulting from a significantly increased transition dipole moment, and iv) reducing the intrinsic triplet nonradiative decay by substitution of high-frequency vibrating hydrogen atoms. All these factors synergistically contribute to the most efficient and stable visible-light-stimulated UL-RTP (lifetime up to 2.01 s and efficiency up to 35.4 % upon excitation at 450 nm) in flexible films using multi-esterified coronene, which allows high-tech applications in single-component time-delayed white light-emitting diodes and information technology based on flashlight-activated afterglow encryption.     

用于355nm紫外激光器的消偏振二向色镜

采用离子束辅助电子束成膜,用双重膜厚监控方法监控各膜层厚度,制备了45°入射、808nm高反、1064nm高透的消偏振二向色镜,并用于全固态355nm激光器.将部分薄膜样品在250℃进行退火处理后,用Lambda950分光光度计测试该样品的光谱性能;用表面热透镜技术测量退火前后该样品的弱吸收值;用激光阈值损伤装置测试该样品在1064nm调Q激光下的损伤阈值;用NIKON显微镜观察样品在不同激光能量辐照下的破斑形貌.实验结果表明:波长为808nm和1 064nm时,薄膜透射率分别为0.04%和99.6%,符合设计要求,满足全固态355nm紫外激光器系统所要求的光学性能指标;退火后的弱吸收值较退火前有所降低;在激光作用下薄膜产生微破坏喷出,说明膜层不会向灾难性破坏演变.     

关联染料敏化太阳能电池薄膜厚度与光伏性能的漂移-扩散数值模拟

建立漂移-扩散模型来模拟敏化电池的电荷分离过程.该模型能够计算在稳态和非稳态条件下光生电子的多步受限扩散及其与电子受体的复合反应.通过对电池的电流-电压曲线的数值模拟,优化了电池的薄膜厚度并获得了最大的光电转换效率.发现膜厚的增加降低了电荷收集效率,但有利于提高电子注入流率,光电流的输出正是受控于这两个因素.复合速率常数严重影响了膜厚优化的结果.较厚的薄膜适合于电子复合被充分抑制的电池,而较薄的薄膜有利于降低快复合电池的电子复合损失.在开路条件下,膜厚的提高会减小电子浓度,在造成光电压的降低的同时会提高电子寿命.     

Self-assembled multilayer films of poor water-soluble copper(II) complexes constructed from dipyrido[3,2-d:2′,3′-f]quinoxaline (Dpq) ligand as well as their fluorescent properties

New multilayer films were prepared by alternating adsorption of poly(sodium 4-styrenesulfonate) (PSS) and a new complex of [Cu₂(Dpq)₂(Ac)₂(H₂O)₂] (ClO₄)₂·H₂O (1) (Dpq=dipyrido[3,2-d:2′,3′-f]quinoxaline, Ac=acetate) or a related complex [Cu(Dpq)₂(H₂O)] (ClO₄)₂·H₂O (1a) by electrostatic layer-by-layer self-assembly technique, respectively. Compounds 1 and 1a have been synthesized and structurally characterized by elemental analyses, IR spectroscopy, and single-crystal X-ray diffraction analyses. Single-crystal X-ray analyses show that complexes 1 and 1a possess a dinuclear and a mononuclear structure, respectively, which are further extended into layered frameworks by π-π stacking and hydrogen-bonding interactions. The multilayer films were characterized by UV-vis spectroscopy, fluorescence spectroscopy, small-angle X-ray reflectivity measurements, and atomic force microscopy (AFM) imaging. UV spectroscopy shows that the deposition process is regular and highly reproducible from layer to layer. AFM image indicates that the film surface is uniform and smooth. The fluorescent properties of the films were studied and the results showed that the forming condition of the films had great influence on their properties.