Perfectly Encoding π-Conjugated Anions in the RE5(C3N3O3)(OH)12 (RE=Y,Yb, Lu) Family with Strong Second Harmonic Generation Response and Balanced Birefringence

Nonlinear optical (NLO) crystal, which simultaneously exhibits strong second-harmonic-generation (SHG) response and desired optical anisotropy, is a core optical material accessible to the modern optoelectronics. Accompanied by strong SHG effect in a NLO crystal, a contradictory problem of overlarge birefringence is ignored, leading to low frequency doubling efficiency and poor beam quality. Herein, a series of rare earth cyanurates RE₅(C₃N₃O₃)(OH)₁₂ (RE=Y, Yb, Lu) were successfully characterized by 3D electron diffraction technique. Based on a “three birds with one stone” strategy, they enable the simultaneous fulfillment of strong SHG responses (2.5–4.2× KH₂PO₄), short UV cutoff (ca. 220 nm) and applicable birefringence (ca. 0.15 at 800 nm) by the introduction of rare earth coordination control of π-conjugated (C₃N₃O₃)³⁻ anions. These findings provide high-performance short-wavelength NLO materials and highlight the exploration of cyanurates as a new research area.     

Basics of optical force

Light possesses momentum, and hence, force is exerted on materials if they absorb and/or scatter light. Laser techniques that use optical forces are currently attracting considerable attention. Optical manipulation for trapping, transporting small particles, and measuring the interparticle force is a representative technique. In addition, photoinduced force microscopy is a promising scanning type of microscopy using optical force. Optical force techniques have recently been used in various fields of research, such as molecular bioscience, organic photochemistry, materials engineering, and molecular fluid dynamics. In these techniques, several types of optical forces such as scattering, absorption, and gradient forces play their respective roles. In this article, we summarize the basics of optical forces and present their elementary expressions for using simplified models of light and matter systems. This will help the readers of this Special Issue to understand how different types of forces are distinguished in the basic expressions used for analyzing the optical force phenomena that appear depending on the light geometry and matter systems. After observing simplified cases of scattering and absorption forces, we introduce general formulae for the optical force and then discuss how different components appear in particular cases of laser geometry and materials.     

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.     

A Hydrogen Bonded Supramolecular Framework Birefringent Crystal

Birefringent crystals could modulate the polarization of light and are widely used as polarizers, waveplates, optical isolators, etc. To date, commercial birefringent crystals have been exclusively limited to purely inorganic compounds such as α-BaB₂O₄ with birefringence of about 0.12. Herein, we report a new hydrogen bonded supramolecular framework, namely, Cd(H₂C₆N₇O₃)₂⋅8 H₂O, which exhibits exceptionally large birefringence up to about 0.60. To the best of our knowledge, the birefringence of Cd(H₂C₆N₇O₃)₂⋅8 H₂O is significantly larger than those of all commercial birefringent crystals and is the largest among hydrogen bonded supramolecular framework crystals. First-principles calculations and structural analyses reveal that the exceptional birefringence is mainly ascribed to strong covalent interactions within (H₂C₆N₇O₃)⁻ organic ligands and the perfect coplanarity between them. Given the rich structural diversity and tunability, hydrogen bonded supramolecular frameworks would offer unprecedented opportunities beyond the traditional purely inorganic oxides for birefringent crystals.     

Design and synthesis of polyindole - ZnO nano composite for NLO applications

Present paper mainly focuses on the synthesis, characterization polyindole-ZnO nano composites for third order nonlinear optical applications. Polyindole was synthesized through oxidative polymerization technique and its composites were prepared with different ZnO concentration. Structural morphology of the polymer composite was studied using FESEM, XRD and UV Visible spectroscopic technique. Polymer showed broad absorption with absorption maxima of 395 nm. Newly prepared thin films showed excellent nonlinear absorption with very good optical limiting behaviour when it is exposed to He-Ne laser with maximum optical limiting power of 11 mW along with third-order nonlinear susceptibility χ⁽³⁾ of 2.72 × 10^?3 esu. Hence these polymer composites may be potential candidate for optical limiting applications.     

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.     

Extraction and characterization of highly pure alumina (α, γ, and θ) polymorphs from waste beverage cans: A viable waste management approach

The recycling and recovery of important materials from inexpensive feedstock has now become an intriguing area and vital from commercial and environmental viewpoints. In the present work, extraction of different single phases of alumina (α, γ, θ-Al₂O₃) having high purity (>99.5 %) from locally available waste beverage cans (～95 % Al) through facile precipitation route calcined at distinct temperatures has been reported. The optimization of process technology was done by a variety of different synthesis parameters, and the production cost was estimated between 84.47-87.45 USD per kg of alumina powder. The as prepared alumina fine particles have been characterized using different sophisticated techniques viz. TG-DTA, WD-XRF, XRD, FT-IR, SEM, DLS-based particle size analysis (PSA) with zeta (ζ) potential measurement and UV–Visible Spectroscopy. X-ray diffractogram confirms the formation of γ-, θ-, and α-alumina at 500–700 °C, 900–1000 °C, and 1200 °C respectively and crystallite size, crystallinity, strain, dislocation density, and specific surface area were measured using major X-ray diffraction peaks which varies with temperature. The SEM studies showed that the as prepared alumina particles were agglomerated, irregular-shaped with particle size (0.23–0.38 µm), pore size, and porosity were calculated from SEM image. ζ-potentials at different pH values as well as isoelectric point (IEP) of α, γ, and θ alumina were calculated in an aqueous medium which changes with temperature. The direct band gap (E_g) energies were found between 4.09 and 5.19 eV of alumina obtained from different calcination temperatures. The synthesized materials can be used in sensors, ceramics, catalysis, and insulation applications.     

Bioanalytical chemistry of cytokines – A review

Cytokines are bioactive proteins produced by many different cells of the immune system. Due to their role in different inflammatory disease states and maintaining homeostasis, there is enormous clinical interest in the quantitation of cytokines. The typical standard methods for quantitation of cytokines are immunoassay-based techniques including enzyme-linked immusorbent assays (ELISA) and bead-based immunoassays read by either standard or modified flow cytometers. A review of recent developments in analytical methods for measurements of cytokine proteins is provided. This review briefly covers cytokine biology and the analysis challenges associated with measurement of these biomarker proteins for understanding both health and disease. New techniques applied to immunoassay-based assays are presented along with the uses of aptamers, electrochemistry, mass spectrometry, optical resonator-based methods. Methods used for elucidating the release of cytokines from single cells as well as in vivo collection methods are described.     

Analytical potential of a laser ablation–glow discharge–optical emission spectrometry system for the analysis of conducting and insulating materials

The analytical capabilities of a glow discharge (GD) as a secondary source for excitation/ionization of the material provided by laser ablation (LA) have been compared to conventional laser induced breakdown spectroscopy (LIBS). In LA–GD both sources can be independently adjusted to optimize the sampling process and then its subsequent excitation. This could involve a number of analytical performance advantages, such as reduced matrix dependence, greater precision and sensitivity than those encountered in LIBS. For such purpose, an ablation chamber design including two electrodes to generate the GD discharge has been built and assayed. A comparison between LIBS and LA–GD–OES has been carried out, both, under reduced argon and helium atmospheres. Different sets of samples (conducting reference materials, glass and fluorine pellets) have been used to evaluate the novel coupled technique. The LA–GD coupled system has shown to provide lower detection limits. In addition, best linear correlations between intensities and concentrations and lower matrix effects have also been found using the coupled system. Moreover, special advantages of the LA–GD–OES have also been demonstrated for the analysis of fluorine.     

A new device for in-line colorimetric quantification of polypropylene degradation under multiple extrusions

An in-line colorimeter that is able to quantify color changes in real time during extrusion was developed and validated. It is composed of LEDs emitting at three different wavelengths and a photocell that measures the intensity of the light transmitted through the polymer melt flow. The colorimeter was validated at the bench by employing colored aqueous solutions and in-line during the extrusion of a colored polypropylene. Furthermore, it was used to in-line quantify the color changes in a polypropylene as generated over multiple extrusions due to thermo-mechanical degradation. The technique was proved to be fast and suitable to measure color changes in real time during extrusion.