Hydrogen‐Bonded Polyimide/Metal‐Organic Framework Hybrid Membranes for Ultrafast Separations of Multiple Gas Pairs

Membranes have seen a growing role in mitigating the extensive energy used for gas separations. Further expanding their effectiveness in reducing the energy penalty requires a fast separation process via a facile technique readily integrated with industrial membrane formation platforms, which has remained a challenge. Here, an ultrapermeable polyimide/metal‐organic framework (MOF) hybrid membrane is reported, enabling ultrafast gas separations for multiple applications (e.g., CO₂ capture and hydrogen regeneration) while offering synthetic enhanced compatibility with the current membrane manufacturing processes. The membranes demonstrate a CO₂ and H₂ permeability of 2494 and 2932 Barrers, respectively, with a CO₂/CH₄, H₂/CH₄, and H₂/N₂ selectivity of 29.3, 34.4, and 23.8, respectively, considerably surpassing the current Robeson permeability–selectivity upper bounds. At a MOF loading of 55 wt%, the membranes display a record‐high 16‐fold enhancement of H₂ permeability comparing with the neat polymer. With mild membrane processing conditions (e.g., a heating temperature less than 80 °C) and a performance continuously exceeding Robeson upper bounds for over 5300 h, the membranes exhibit enhanced compatibility with state‐of‐the‐art membrane manufacturing processes. This performance results from intimate interactions between the polymer and MOFs via extensive, direct hydrogen bonding. This design approach offers a new route to ultraproductive membrane materials for energy‐efficient gas separations.     

Densely Functionalized Cyanographene Bypasses Aqueous Electrolytes and Synthetic Limitations Toward Seamless Graphene/β‐FeOOH Hybrids for Supercapacitors

Supercapacitors are a promising energy storage technology owing to their unparalleled power and lifetime. However, to meet the continuously rising demands of energy storage, they must be equipped with higher energy densities. For this purpose, the seamless integration of metal oxides on carbon matrices, such as iron oxides/oxyhydroxides, has been pursued through hydrothermal, atomic layer and electro‐deposition methods directly on current collectors. Nevertheless, such methods present limited compatibility with commercial paste‐coating processes on the current collectors. Furthermore, iron oxides/oxyhydroxides lack conductivity and are hydrophilic, operating with low‐voltage aqueous electrolytes, limiting their power and energy and requiring corrosion‐resistant H₂O current collectors. To mitigate these challenges, a seamless and paste‐ready material is successfully developed through a 15 min wet‐chemical method, via the coordination of ultrasmall β‐FeOOH (akaganéite) nanoparticles to the nitrile groups of a covalent graphene derivative. Endowed with graphene‐like impedance response and very high wettability in organic electrolytes, combined high power and energy densities are obtained, with respect to the total mass of both electrode materials and current collectors, overcoming the identified challenges. This offers future prospects for the exploration of alternative molecular handles for improved interfaces and their application in different energy‐storage chemistries.     

Humidity‐Resistive Triboelectric Nanogenerator Fabricated Using Metal Organic Framework Composite

With its light weight, low cost, and high efficiency, the triboelectric nanogenerator (TENG) is considered a sustainable and renewable energy source for self‐powered or mobile electronics. However, the performance of TENG is seriously affected by humid environment. Here, for the first time, TENG with improved performance under high humidity is obtained by adding HKUST‐1 (Cu₃(BTC)₂, (BTC = 1,3,5‐benzenetricarboxylate or trimesate)) to polydimethylsiloxane (PDMS) matrix. At 10% relative humidity (RH), an effective power (3.17 mW) of the composite TENG based on 5 wt% HKUST‐1 is obtained at a load resistance of 10 MΩ, which is 13 times higher than that of the TENG based on pure PDMS. More importantly, the performance of composite TENG remains constant or becomes higher even under high humidity, while that of conventional TENG dramatically decreases at the same condition. The excellent humidity‐resistive performance comes from the remarkably enhanced electron‐trapping capacity and dielectric constant due to the absorption of HKUST‐1 to water molecules. This work not only demonstrates that a metal organic framework is an effective filler to improve the performance of TENG but also provides a novel strategy to obtain high output properties under highly humid environments by increasing the electron‐trapping capacity and dielectric constant.     

A Solvent‐Free Solution: Vacuum‐Deposited Organic Monolayers Modify Work Functions of Noble Metal Electrodes

The energy level alignment between organic semiconductors (OSCs) and the respective (metal) electrodes in organic electronic devices is of key importance for efficient charge carrier injection. For many years, researchers have attempted to control this energy level alignment by means of functional self‐assembled monolayers or the insertion of thin injection layers (made, e.g., of doped OCSs or pure dopants). The present work demonstrates an alternative to these approaches, namely the use of phthalocyanine monolayers as contact primers, which are deposited onto noble metal electrodes by means of vacuum deposition. It is shown that polar as well as non‐polar phthalocyanines modify the work functions of clean Au(111) and Ag(111) surfaces as a function of their coverage and thus enable quantitative control of the metal work functions. This behavior is successfully replicated for the respective polycrystalline metal surfaces and it is found that full monolayers can even withstand air exposure when protected by sacrificial multilayers, which are afterward removed by thermal desorption.     

Rapid Detection of the Biomarkers for Carcinoid Tumors by a Water Stable Luminescent Lanthanide Metal–Organic Framework Sensor

Serotonin (5‐hydroxytryptamine, HT), a neurotransmitter, and its main metabolite 5‐hydroxyindole‐3‐acetic acid (HIAA) are biomarkers for carcinoid tumors. They can be quantitatively detected by a new luminescent sensor based on a water stable lanthanide metal–organic framework (Ln‐MOF). This Ln‐MOF features a (3,4)‐connected topology containing 1D channels occupied by lattice water molecules. Luminescent studies reveal that high luminescence quenching efficiency occurs upon the addition of HT and HIAA. The Ln‐MOF also displays excellent sensitivity with fast response within 1 min, good reusability, and detection limits as low as 0.66 and 0.54 × 10^?6m for HT and HIAA, respectively. In addition, the sensing function exhibits excellent selectivity even in the presence of other neurotransmitters and the main coexisting species in blood plasma and urine.     

Highly Efficient Pure‐White‐Light‐Emitting Diodes from a Single Polymer: Polyfluorene with Naphthalimide Moieties

Light‐emitting diodes exhibiting efficient pure‐white‐light electroluminescence have been successfully developed by using a single polymer: polyfluorene derivatives with 1,8‐naphthalimide chromophores chemically doped onto the polyfluorene backbones. By adjusting the emission wavelength of the 1,8‐naphthalimide components and optimizing the relative content of 1,8‐naphthalimide derivatives in the resulting polymers, white‐light electroluminescence from a single polymer, as opposed to a polymer blend, has been obtained in a device with a configuration of indium tin oxide/poly(3,4‐ethylenedioxythiophene)(50 nm)/polymer(80 nm)/Ca(10 nm)/Al(100 nm). The device exhibits Commission Internationale de l'Eclairage coordinates of (0.32,0.36), a maximum brightness of 11 900 cd m^–2, a current efficiency of 3.8 cd A^–1, a power efficiency of 2.0 lm W^–1, an external quantum efficiency of 1.50 %, and quite stable color coordinates at different driving voltages, even at high luminances of over 5000 cd m^–2.     

Solution‐Processed Organic Tandem Solar Cells

A solution‐processed polymer tandem cell fabricated by stacking two single cells in series is demonstrated. The two bulk‐heterojunction subcells have complementary absorption maxima at λ_max ～ 850 nm and λ_max ～ 550 nm, respectively. A composite middle electrode is applied that serves both as a charge‐recombination center and as a protecting layer for the first cell during spin‐coating of the second cell. The subcells are electronically coupled in series, which leads to a high open‐circuit voltage of 1.4 V, equal to the sum of each subcell. The layer thickness of the first (bottom) cell is tuned to maximize the optical absorption of the second (top) cell. The performance of the tandem cell is presently limited by the relatively low photocurrent generation in the small‐bandgap polymer of the top cell. The combination of our tandem architecture with more efficient small‐bandgap materials will enable the realization of highly efficient organic solar cells in the near future.     

Luminescence Properties of Aminobenzanthrones and Their Application as Host Emitters in Organic Light‐Emitting Devices

A series of aminobenzanthrone derivatives, possessing a keto and an amino group on the aromatic ring, are synthesized and their photoluminescence (PL) and electroluminescence (EL) properties are studied in detail. These compounds emit strongly in solution and in the solid state, with the emission maxima in the range of 528–668 nm resulting from charge‐transfer transitions from the amino group to the keto moiety. The emission wavelength depends greatly on the polarity of the solvent. A red shift of nearly 100 nm is observed from n‐hexane to dichloromethane for each of these compounds. The PL quantum yields of these molecules also depend tremendously on the solvent. The values are between 88 and 70 % in n‐hexane and decrease as the polarity of the solvent increases. The single‐crystal X‐ray diffraction data reveal that the aminobenzanthrone planes of these molecules stack in the crystals in an antiparallel head‐to‐tail fashion. This strong dipole–dipole interaction accounts for the observed red‐shifted emissions of the aminobenzanthrone molecules in powders and in films relative to those in nonpolar solvents. Electroluminescent devices using aminobenzanthrone derivatives as the host emitters or dopants emit orange to red light in the range 590–645 nm. High brightness, current efficiency, and power efficiency are observed for some of these devices. For example, the device using N‐(4‐t‐butylphenyl)‐N‐biphenyl‐3‐benzanthronylamine as the emitter gives saturated red light with a current efficiency of 1.82 cd A^–1, brightness of 11 253 cd m^–2, and Commission Internationale de l'Éclairage (CIE) coordinates of (0.64,0.36); the device using N‐(2‐naphthyl)‐N‐phenyl‐3‐benzanthronylamine as the emitter gives orange–red light with a current efficiency of 3.52 cd A^–1, brightness of 25 000 cd m^–2, and CIE coordinates of (0.61,0.38).     

Aggregation‐induced Emission (AIE)‐active Starburst Triarylamine Fluorophores as Potential Non‐doped Red Emitters for Organic Light‐emitting Diodes and Cl2 Gas Chemodosimeter

A new series of starburst triarylamine fluorophores SBCHO, DBCHO, CZCHO, CZCN, and SBCN, that incorporate diphenylamine or carbazole as the electron donor and dicyanovinyl or aldehyde as the electron acceptor, has been prepared and their photophysical properties are investigated. In sharp contrast to most red‐emitting dopants, which show serious aggregation‐caused quench phenomena, the new starburst triphenylamine derivatives reported here show unique enhanced emission in the solid state or upon aggregation. Organic light emitting diodes using these compounds as non‐doped host emitters and hole transporters have been fabricated. The highest external quantum yield reaches 2.09 % for CZCHO. SBCHO was investigated as a chlorine gas fluorescence (FL) solid‐film sensor for the first time. The high‐intensity emission was ‘turned off' immediately after being blown by Cl₂ gas.     

NH3 对二甲苯光氧化形成二次有机气溶胶的影响

二甲苯是一种重要的人为源 VOC, 也是城市地区 SOA 的重要前体物。二甲苯光氧化形成的 SOA 受多种环 境因素影响, 而 NH3 对该反应形成的 SOA 生成产率及反应机制的影响尚不清楚。基于室内烟雾箱模拟系统, 探讨了 NH3 对二甲苯光氧化形成 SOA 质量浓度、物理特性及化学组成的影响。研究表明, 在低浓度条件下, NH3 对二甲苯 光氧化生成 SOA 具有明显的促进作用, 结合气溶胶质谱结果发现 NH3 促进醛酮类物质进入颗粒相以及含氮有机物的 生成是导致 SOA 质量浓度增加的主要原因。此外, NH3 能够提高邻二甲苯生成 SOA 的吸光度, 但是对对二甲苯无明 显影响。分析表明, 相较于对二甲苯, 邻二甲苯光氧化会生成大量醛类物质, NH3 与醛类发生美拉德反应是导致 SOA 吸光性增加的主要原因。