Robust and Wide Temperature-Range Zinc Metal Batteries with Unique Electrolyte and Substrate Design

Rechargeable zinc metal batteries are promising for large-scale energy storage. However, their practical application is limited by harsh issues such as uncontrollable dendrite growth, low Coulombic efficiency, and poor temperature tolerance. Herein, a unique design strategy using γ-valerolactone-based electrolyte and nanocarbon-coated aluminum substrate was reported to solve the above problems. The electrolyte with extremely low freezing point and high thermal stability enables the symmetric cells with long cycle life over a wide temperature range (−50 °C to 80 °C) due to its ability to regulate zinc nucleation and preferential epitaxial growth. Besides, the nanocarbon-coated aluminum substrate can also promote a higher Coulombic efficiency over a wide temperature range in contrast to the low Coulombic efficiency of copper substrates with significant irreversible alloying reactions because this unique substrate with excellent chemical stabilization can homogenize the interfacial electron/ion distribution. The optimized zinc metal capacitors can operate stably under various temperature conditions (2000 cycles at 30 °C with 66 % depth of discharge and 1200 cycles at 80 °C with 50 % depth of discharge). This unique electrolyte and substrate design strategy achieves a robust zinc metal battery over a wide temperature range.     

Modulating Triplet Excited States of Organic Semiconductors via Tuning Molecular Conformation for Dual-ratiometric Thermometers

The dual-ratiometric thermometry is one of highly accurate methods for microscopic thermal measurement in biological systems. Herein, a series of chromone derivatives with noncovalently intramolecular interactions (NIIs) were designed and synthesized for ratiometric thermometers. The triplet states of these organic compounds were systematically tuned upon regulating the conformation with NIIs to yield efficient room temperature phosphorescence and large wavelength difference between fluorescence and phosphorescence simultaneously. As a result, an unprecedent organic 3D dual-ratiometric thermometer was established based on the intensity ratio and lifetime ratio of fluorescence/phosphorescence vs temperature, which was used for in vitro and in vivo bio-thermometry with high accuracy. This work provides a novel method to achieve organic dual ratiometric thermometers via tuning the triplet excited states.     

Supercooled Liquids with Dynamic Room Temperature Phosphorescence Using Terminal Hydroxyl Engineering

Dynamic room temperature phosphorescence (RTP) materials have potential applications in optoelectronics, which inevitably suffer from poor processability, flexibility or stretchability. Herein, we report a concise strategy to develop supercooled liquids (SCLs) with dynamic RTP behavior using terminal hydroxyl engineering. The terminal hydroxyls effectively hinder the nucleation process of molecules for the formation of stable SCLs after thermal annealing. Impressively, the SCLs show reversible RTP emission via alternant stimulation by UV light and heat. Photoactivated SCLs have phosphorescent efficiency of 8.50 % and a lifetime of 31.54 ms under ambient conditions. Regarding the dynamic RTP behavior and stretchability of SCLs, we demonstrate the applications in erasable data encryption and patterns on flexible substrates. This finding provides a design principle for obtaining SCLs with RTP and expands the potential applications of RTP materials in flexible optoelectronics.     

Ultralow-loss Optical Waveguides through Balancing Deep-Blue TADF and Orange Room Temperature Phosphorescence in Hybrid Antimony Halide Microstructures

Harnessing the potential of thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) is crucial for developing light-emitting diodes (LEDs), lasers, sensors, and many others. However, effective strategies in this domain are still relatively scarce. This study presents a new approach to achieving highly efficient deep-blue TADF (with a PLQY of 25 %) and low-energy orange RTP (with a PLQY of 90 %) through the fabrication of lead-free hybrid halides. This new class of monomeric and dimeric 0D antimony halides can be facilely synthesized using a bottom-up solution process, requiring only a few seconds to minutes, which offer exceptional stability and nontoxicity. By leveraging the highly adaptable molecular arrangement and crystal packing modes, the hybrid antimony halides demonstrate the ability to self-assemble into regular 1D microrod and 2D microplate morphologies. This self-assembly is facilitated by multiple non-covalent interactions between the inorganic cores and organic shells. Notably, these microstructures exhibit outstanding polarized luminescence and function as low-dimensional optical waveguides with remarkably low optical-loss coefficients. Therefore, this work not only presents a pioneering demonstration of deep-blue TADF in hybrid antimony halides, but also introduces 1D and 2D micro/nanostructures that hold promising potential for applications in white LEDs and low-dimensional photonic systems.     

A Polarized Gel Electrolyte for Wide-Temperature Flexible Zinc-Air Batteries

The development of flexible zinc-air batteries (FZABs) has attracted broad attention in the field of wearable electronic devices. Gel electrolyte is one of the most important components in FZABs, which is urgent to be optimized to match with Zn anode and adapt to severe climates. In this work, a polarized gel electrolyte of polyacrylamide-sodium citric (PAM-SC) is designed for FZABs, in which the SC molecules contain large amount of polarized −COO⁻ functional groups. The polarized −COO⁻ groups can form an electrical field between gel electrolyte and Zn anode to suppress Zn dendrite growth. Besides, the −COO⁻ groups in PAM-SC can fix H₂O molecules, which prevents water from freezing and evaporating. The polarized PAM-SC hydrogel delivers a high ionic conductivity of 324.68 mS cm⁻¹ and water retention of 96.85 % after being exposed for 96 h. FZABs with the PAM-SC gel electrolyte exhibit long cycling life of 700 cycles at −40 °C, showing the application prospect under extreme conditions.     

Diboraanthracene-Doped Polymer Systems for Colour-Tuneable Room-Temperature Organic Afterglow

Organic ultralong room temperature phosphorescence (RTP), or organic afterglow, is a unique phenomenon, gaining widespread attention due to its far-reaching application potential and fundamental interest. Here, two laterally expanded 9,10-dimesityl-dihydro-9,10-diboraanthracene (DBA) derivatives are demonstrated as excellent afterglow materials for red and blue-green light emission, which is traced back to persistent thermally activated delayed fluorescence and RTP. The lateral substitution of polycyclic DBA scaffold, together with weak transversal electron-donating mesityl groups, ensures the optimal molecular properties for (reverse) intersystem crossing and long-lived triplet states in a rigid poly(methyl methacrylate) matrix. The achieved afterglow emission quantum yields of up to 3 % and 15 %, afterglow lifetimes up to 0.8 s and 3.2 s and afterglow durations up to 5 s and 25 s (for red and blue-green emitters, respectively) are attributed to the properties of single molecules.     

ZIF-8衍生的具有可控氧空位的ZnO对光催化去除NO的增强及毒性NO2形成的抑制

氧化锌作为一种半导体材料,具有合适的能带结构位置,高催化效率,低成本和环境可持续性,因而广泛用于光催化领域.然而,由于氧化锌的宽带隙,可见光吸收能力差以及光生电子-空穴对的快速复合,极大地影响了其光催化效率.通过引入氧空位调控光催化剂的结构被证明是一种可以改善光生载流子的分离,从而提高光催化性能的有效方法.本文以ZIF-8为前驱体,采用两步煅烧法合成了具有不同浓度氧空位分布的ZnO纳米光催化剂,通过X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、紫外-可见漫反射光谱(UV-Vis DRS)、X射线光电子能谱(XPS)、电子顺磁共振(EPR)、荧光光谱仪(PL)等手段系统地分析了合成的光催化剂的理化性质,并评价了它们在可见光下光催化氧化去除NO反应性能.EPR结果表明,样品中氧空位的浓度取决于温度处理的过程.通过两步煅烧法得到氧化锌中氧空位的含量高于一步直接煅烧法所得的样品.此外,随着煅烧温度升高,合成的氧化锌晶格越完好,其氧空位含量越少.UV-Vis DRS结果表明,两步煅烧法合成的ZnO与商业的ZnO及一步法直接煅烧合成的ZnO相比,其吸光范围从紫外光拓展到了可见光,表现出了更加优异的吸光性能.光催化反应结果表明,与商业氧化锌和一步直接煅烧法所得样品相比,两步煅烧法合成的样品表现出了更优异的光催化去除NO性能,并抑制了中间产物毒性NO2的产生,促进了NO的深度氧化.具体反应路径为:在光照过程中,光生电子很容易被氧空位俘获,与O2反应产生更多的超氧自由基(·O2^-),从而将NO氧化成最终的产物硝酸盐.尤其有趣的是,先在350 ℃煅烧2小时再400℃煅烧1小时的两步法样品Z 350-400的NO去除效率分别比一步法样品Z 400(400℃煅烧)和商用ZnO高出1.5和4.6倍.这表明以MOF材料衍生的具有适当量氧空位的金属氧化物为一种高效去除NO的光催化剂具有很好的应用前景.     

Preparation of temperature sensitive molecularly imprinted polymer for solid-phase microextraction coatings on stainless steel fiber to measure ofloxacin

A kind of new temperature sensitive molecularly imprinted polymer (MIP) with ofloxacin (OFL) as template was prepared for the coating of solid phase microextraction (SPME). Dopamine was self-polymerized on stainless steel fiber (SSF) as the SPME support followed by silanization. Then MIP was synthesized as SPME coating on the modified SSF in a capillary, with N-isopropyl acrylamide as temperature sensitive monomer and methacrylic acid as functional monomer. The synthesis could be well repeated with multiple capillaries putting in the same reaction solution. The obtained MIP fiber was evaluated in detail with different techniques and various adsorption experiments. At last the MIP fiber was used to extract the OFL in milk. Satisfied recoveries between 89.7 and 103.4% were obtained with the limit of quantification (LOQ_LC) of 0.04 μg mL⁻¹ by the method of SPME coupled with high performance of liquid chromatography (HPLC).     

A high performance system to study the influence of temperature in on-line solid-phase extraction capillary electrophoresis

A novel high performance system to control the temperature of the microcartridge in on-line solid phase extraction capillary electrophoresis (SPE–CE) is introduced. The mini-device consists in a thermostatic bath that fits inside of the cassette of any commercial CE instrument, while its temperature is controlled from an external circuit of liquid connecting three different water baths. The circuits are controlled from a switchboard connected to an array of electrovalves that allow to rapidly alternate the water circulation through the mini-thermostatic-bath between temperatures from 5 to 90 °C. The combination of the mini-device and the forced-air thermostatization system of the commercial CE instrument allows to optimize independently the temperature of the sample loading, the clean-up, the analyte elution and the electrophoretic separation steps.     

Thermodynamic studies on protonation constant of adenosine and guanosine at different temperatures and ionic strengths

Stepwise protonation constants of two purine nucleosides (adenosine and guanosine) were determined at different temperatures (293.15 to 308.15) and various ionic strengths (0.101 to 3.503 mol · kg⁻¹ NaClO₄) using a combination of potentiometric and spectrophotometric method. The thermodynamic parameters (i.e. enthalpy change, ΔH, and entropy change, ΔS) of the protonations were calculated at different temperatures using van’t Hoff and virial equations. The dependence of the protonation constant on ionic strength is modeled by a Debye–Hückel type equation and discussed. Finally, the protonation constants of the nucleosides and the enthalpy change of protonations were determined at zero ionic strength.