Luminescent Units Research Articles

Polymer Acceptor Copolymerized with Luminescent Unit for High‐Performance All‐Polymer Solar Cells with Low Non‐radiative Energy Loss

AbstractReduction of non‐radiative energy loss (ΔEnr) in all‐polymer solar cells (all‐PSCs) is crucially important for achieving high power conversion efficiencies (PCEs). Herein, an efficient strategy is reported to reduce the ΔEnr by introducing luminescent unit into the backbone of polymer acceptors. Compared to the device based on PM6:PYDT, the ΔEnr in all‐PSC based on PM6:PYDT‐CzP‐9 has decreased from 0.188 to 0.183 eV. This reduction is attributed to the improvement in electroluminescence external quantum efficiency (EQEEL). The PM6:PYDT‐CzP‐9 device has shown an 18% increase in EQEEL compared to the device based on PM6:PYDT (8.4 × 10−4 vs 7.1 × 10−4), demonstrating that the incorporation of luminescent unit in polymer acceptors is highly effective in enhancing the electroluminescence performance of all‐PSCs. As a result, the PM6:PYDT‐CzP‐9 device yielded a high VOC of 0.967 V, without the sacrifice of short‐circuit current density (23.42 mA cm−2) and fill factor (77.5%), leading to a high PCE of 17.55%.

CRISPR/Cas12a-drived electrochemiluminescence and fluorescence dual-mode magnetic biosensor for sensitive detection of Pseudomonas aeruginosa based on iridium(III) complex as luminophore

The opportunistic human pathogen Pseudomonas aeruginosa (P. aeruginosa) poses a significant threat to human health, causing sepsis, inflammation, and pneumonia, so it is crucial to devise an expeditious detection platform for the P. aeruginosa. In this work, bis (2- (3, 5- dimethylphenyl) quinoline- C2, N′) (acetylacetonato) iridium (III) Ir (dmpq)2 (acac) with excellent electrochemiluminescence (ECL) and fluorescence (FL) and magnetic nanoparticles were encapsulated in silica spheres. The luminescent units exhibited equal ECL and FL properties compared with single iridium complexes, and enabled rapid separation, which was of vital significance for the establishment of biosensors with effective detection. In addition, the luminescent units were further reacted with the DNA with quenching units to obtain the signal units, and the ECL/FL dual-mode biosensor was employed with the CRISPR/Cas12a system to further improve its specific recognition ability. The ECL detection linear range of as-proposed biosensor in this work was 100 fM-10 nM with the detection limit of 73 fM (S/N = 3), and FL detection linear range was 1 pM–10 nM with the detection limit of 0.126 pM (S/N = 3). Importantly, the proposed dual-mode biosensor exhibited excellent repeatability and stability in the detection of P. aeruginosa in real samples, underscoring its potential as an alternative strategy for infection prevention and safeguarding public health and safety in the future.

Adaptive Helical Chirality in Supramolecular Microcrystals for Circularly Polarized Lasing

AbstractChiral organic molecules offer a promising platform for exploring circularly polarized lasing, which, however, faces a great challenge that the spatial separation of molecular chiral and luminescent centers limits chiroptical activity. Here we develop a helically chiral supramolecular system with completely overlapped chiral and luminescent units for realizing high‐performance circularly polarized lasing. Adaptive helical chirality is obtained by incorporating chiral agents into organic microcrystals. Benefiting from the efficient coupling of stimulated emission with the adaptive helical chirality, the supramolecular microcrystals enable high‐performance circularly polarized lasing emission with dissymmetry factors up to ~0.7. This work opens up the way to rational design of chiral organic materials for circularly polarized lasing.

Adaptive Helical Chirality in Supramolecular Microcrystals for Circularly Polarized Lasing.

Chiral organic molecules offer a promising platform for exploring circularly polarized lasing, which, however, faces a great challenge that the spatial separation of molecular chiral and luminescent centers limits chiroptical activity. Here we develop a helically chiral supramolecular system with completely overlapped chiral and luminescent units for realizing high-performance circularly polarized lasing. Adaptive helical chirality is obtained by incorporating chiral agents into organic microcrystals. Benefiting from the efficient coupling of stimulated emission with the adaptive helical chirality, the supramolecular microcrystals enable high-performance circularly polarized lasing emission with dissymmetry factors up to ~0.7. This work opens up the way to rational design of chiral organic materials for circularly polarized lasing.

Continuous tuning of persistent luminescence wavelength by intermediate-phase engineering in inorganic crystals

Multicolor tuning of persistent luminescence has been extensively studied by deliberately integrating various luminescent units, known as activators or chromophores, into certain host compounds. However, it remains a formidable challenge to fine-tune the persistent luminescence spectra either in organic materials, such as small molecules, polymers, metal-organic complexes and carbon dots, or in doped inorganic crystals. Herein, we present a strategy to delicately control the persistent luminescence wavelength by engineering sub-bandgap donor-acceptor states in a series of single-phase Ca(Sr)ZnOS crystals. The persistent luminescence emission peak can be quasi-linearly tuned across a broad wavelength range (500–630 nm) as a function of Sr/Ca ratio, achieving a precision down to ~5 nm. Theoretical calculations reveal that the persistent luminescence wavelength fine-tuning stems from constantly lowered donor levels accompanying the modified band structure by Sr alloying. Besides, our experimental results show that these crystals exhibit a high initial luminance of 5.36 cd m−2 at 5 sec after charging and a maximum persistent luminescence duration of 6 h. The superior, color-tunable persistent luminescence enables a rapid, programable patterning technique for high-throughput optical encryption.

Detection of ascorbic acid by persistent luminescent nanoparticles based on CoOOH nanosheets modification.

Persistent luminescent nanomaterials (PLNPs) Zn0.8Ga2O4: Cr3+, Zr3+ with high brightness and good dispersion were prepared by hydrothermal method. The PLNPs were used as luminescent units, and CoOOH nanosheets were used as quenching agents. Based on the fluorescence internal filtering effect, the luminescence of PLNPs were effectively quenched by CoOOH modification on the surface of PLNPs. However, the introduction of ascorbic acid (AA) restored the luminescence of PLNPs and successfully achieved highly sensitive and selective detection of AA. This was due to a selective redox reaction between CoOOH and AA, in which CoOOH was reduced to Co2+. The degree of luminescence recovery of PLNPs showed a good linear relationship with AA concentration in the range 5-250 µM, with a detection limit of 0.72 µM. Therecovery of actualspikedsamples were 97.9-102.2%. This method isexpected to provide reference for the study of other redox substances in biological systems.

Pyridinium‐Yne Click Polymerization: A Facile Strategy toward Functional Poly(Vinylpyridinium Salt)s with Multidrug‐Resistant Bacteria Killing Ability

AbstractPolymeric materials with antibacterial properties hold great promise for combating multidrug‐resistant bacteria, which pose a significant threat to public health. However, the synthesis of most antibacterial polymers typically involves complicated and time‐consuming procedures. In this study, we demonstrate a simple and efficient strategy for synthesizing functional poly(vinylpyridinium salt)s via pyridinium‐yne click polymerization. This click polymerization could proceed with high atom economy under mild conditions without any external catalyst, yielding soluble and thermally stable poly(vinylpyridinium salt)s with satisfactory molecular weights and well‐defined structures in excellent yields. Additionally, the incorporation of luminescent units such as fluorene, tetraphenylethylene, and triphenylamine into the polymer backbone confers excellent aggregation‐enhanced emission properties upon the resulting polymers, rendering them suitable for bacterial staining. Moreover, the existence of pyridinium salt imparts intrinsic antibacterial activity against multidrug‐resistant bacteria to the polymers, enabling them to effectively inhibit wound bacterial infection and significantly expedite the healing process. This work not only provides an efficient method to prepare antibacterial polymers, but also opens up the possibility of various applications of polymers in healthcare and other antibacterial fields.

Pyridinium-Yne Click Polymerization: A Facile Strategy toward Functional Poly(Vinylpyridinium Salt)s with Multidrug-Resistant Bacteria Killing Ability.

Polymeric materials with antibacterial properties hold great promise for combating multidrug-resistant bacteria, which pose a significant threat to public health. However, the synthesis of most antibacterial polymers typically involves complicated and time-consuming procedures. In this study, we demonstrate a simple and efficient strategy for synthesizing functional poly(vinylpyridinium salt)s via pyridinium-yne click polymerization. This click polymerization could proceed with high atom economy under mild conditions without any external catalyst, yielding soluble and thermally stable poly(vinylpyridinium salt)s with satisfactory molecular weights and well-defined structures in excellent yields. Additionally, the incorporation of luminescent units such as fluorene, tetraphenylethylene, and triphenylamine into the polymer backbone confers excellent aggregation-enhanced emission properties upon the resulting polymers, rendering them suitable for bacterial staining. Moreover, the existence of pyridinium salt imparts intrinsic antibacterial activity against multidrug-resistant bacteria to the polymers, enabling them to effectively inhibit wound bacterial infection and significantly expedite the healing process. This work not only provides an efficient method to prepare antibacterial polymers, but also opens up the possibility of various applications of polymers in healthcare and other antibacterial fields.

Fluorescent hydrogel with high toughness response based on lanthanide Metals: Material Adhesion, multicolor Modulation, information encryption

Natural polymer-based luminescent materials (NPLMs) are widely used in various fields of science and technology during the high-tech era. This study describes the formation of polyacrylamide (PAM) by thermally initiated free radical in situ polymerization of acrylamide monomer. The resulting hydrogel is physically entangled and chemically crosslinked with hypromellose (HPMC) to create a three-dimensional network structure. Lanthanide organic compatibilizers (Ln-L) are then introduced as luminescent units to produce fluorescent hydrogel materials. The study found that the tensile strength of PAM/HPMC/Ln (0/6 Eu/Tb) hydrogel increased by 230.53 % from 11.76 to 27.11 MPa. Similarly, the compressive strength increased by 208.30 % from 16.14 to 33.62 MPa. Additionally, by adjusting the molar ratio of lanthanide metals, hydrogels can achieve colorful fluorescence modulation. Moreover, an information encryption function was implemented using a Python design program in combination with the fluorescent properties of hydrogels.

Multifunctional self-refrigerated multivariate {GdLn} (Ln = Dy, Tb, Tb/Eu) metal–organic frameworks

"Self-refrigerated" multifunctional MOFs combine Gd for optimal magnetocalorics with other lanthanides (Dy, Tb, Eu) as single-molecule magnets and/or luminescent units, offering exciting possibilities for information storage and processing.

Electrochemiluminescence Sensor Based on CeO2 Nanocrystalline for Hg2+ Detection in Environmental Samples.

The excessive concentration of heavy-metal mercury ions (Hg2+) in the environment seriously affects the ecological environment and even threatens human health. Therefore, it is necessary to develop rapid and low-cost determination methods to achieve trace detection of Hg2+. In this paper, an Electrochemiluminescence (ECL) sensing platform using a functionalized rare-earth material (cerium oxide, CeO2) as the luminescent unit and an aptamer as a capture unit was designed and constructed. Using the specific asymmetric matching between Hg2+ and thymine (T) base pairs in the deoxyribonucleic acid (DNA) single strand, the "T-Hg-T" structure was formed to change the ECL signal, leading to a direct and sensitive response to Hg2+. The results show a good linear relationship between the concentration and the response signal within the range of 10 pM-100 µM for Hg2+, with a detection limit as low as 0.35 pM. In addition, the ECL probe exhibits a stable ECL performance and excellent specificity for identifying target Hg2+. It was then successfully used for spiked recovery tests of actual samples in the environment. The analytical method solves the problem of poor Hg2+ recognition specificity, provides a new idea for the efficient and low-cost detection of heavy-metal pollutant Hg2+ in the environment, and broadens the prospects for the development and application of rare-earth materials.

Photoswitchable and Reversible Fluorescent Eutectogels for Conformal Information Encryption.

Smart fluorescent materials that can respond to environmental stimuli are of great importance in the fields of information encryption and anti-counterfeiting. However, traditional fluorescent materials usually face problems such as lack of tunable fluorescence and insufficient surface-adaptive adhesion, hindering their practical applications. Herein, inspired by the glowing sucker octopus, we present a novel strategy to fabricate a reversible fluorescent eutectogel with high transparency, adhesive and self-healing performance for conformal information encryption and anti-counterfeiting. Using anthracene as luminescent unit, the eutectogel exhibits photoswitchable fluorescence and can therefore be reversibly written/erased with patterns by non-contact stimulation. Additionally, different from mechanically irreversible adhesion via glue, the eutectogel can adhere to various irregular substrates over a wide temperature range (-20 to 65 °C) and conformally deform more than 1000 times without peeling off. Furthermore, by exploiting surface-adaptive adhesion, high transparency and good stretchability of the eutectogel, dual encryption can be achieved under UV and stretching conditions to further improve the security level. This study should provide a promising strategy for the future development of advanced intelligent anti-counterfeiting materials.

Photoswitchable and Reversible Fluorescent Eutectogels for Conformal Information Encryption

AbstractSmart fluorescent materials that can respond to environmental stimuli are of great importance in the fields of information encryption and anti‐counterfeiting. However, traditional fluorescent materials usually face problems such as lack of tunable fluorescence and insufficient surface‐adaptive adhesion, hindering their practical applications. Herein, inspired by the glowing sucker octopus, we present a novel strategy to fabricate a reversible fluorescent eutectogel with high transparency, adhesive and self‐healing performance for conformal information encryption and anti‐counterfeiting. Using anthracene as luminescent unit, the eutectogel exhibits photoswitchable fluorescence and can therefore be reversibly written/erased with patterns by non‐contact stimulation. Additionally, different from mechanically irreversible adhesion via glue, the eutectogel can adhere to various irregular substrates over a wide temperature range (−20 to 65 °C) and conformally deform more than 1000 times without peeling off. Furthermore, by exploiting surface‐adaptive adhesion, high transparency and good stretchability of the eutectogel, dual encryption can be achieved under UV and stretching conditions to further improve the security level. This study should provide a promising strategy for the future development of advanced intelligent anti‐counterfeiting materials.

Non-Classical Circularly Polarized Luminescence Control of Peptide Luminophore Based on Precise Chiral Space Control

Light that rotates in a circular spiral when viewed from the front is known as circularly polarized luminescence (CPL), and can be divided into two types, namely, left- and right-rotating light. To emit both left- and right-rotating CPLs, two types of optically active luminophores, namely, enantiomer D- and L-bodies, are generally required. This mini-review mainly discusses our latest study on CPL properties via the control of the pyrene ring as the luminescent unit incorporated into chiral peptides. In this study, optically active peptide–pyrene organoluminescent materials that emit CPL were synthesized by combining a peptide as a frame and two pyrene rings as a luminescent unit. By adjusting the interpyrene distance, external conditions, and absolute chiral configuration (D- or L-configuration), the chiral spatial configuration of the luminescent pyrene ring was precisely controlled. Consequently, the direction of CPL rotation from pyrenylalanine-containing peptides with the same configuration was successfully controlled.

Plasmon-Controlled Selective Emission Enhancement of Eu3+ with (Au Core)@(Y(V,P)O4:Eu) Nanostructures.

Plasmonic nanostructures have a capability to control the photoluminescence (PL) emission properties of optical species and thus can dramatically enhance the performances of diverse optical systems and devices. Lanthanide ions typically exhibit multiple PL emission lines. Systematic studies on the plasmon-enabled selective enhancement for the different emission lines of lanthanide ions are still highly desired in order to achieve the fine manipulation on the spectral profile and luminescence intensity ratio (LIR). Herein we report on the synthesis and PL emission properties of monodisperse spherical (Au core)@(Y(V,P)O4:Eu) nanostructures, which integrate the plasmonic and luminescent units into an individual core@shell structure. The localized surface plasmon resonance adjusted through control of the size of the Au nanosphere core enables the systematic modulation of the selective emission enhancement of Eu3+. As revealed by single-particle scattering and PL measurements, the five luminescence emission lines of Eu3+ originating from the 5D0,1 excitation states are affected by the localized plasmon resonance to different extents, which are dependent on both the dipole transition nature and the intrinsic quantum yield of the emission line. Based on the plasmon-enabled tunable LIR, high-level anticounterfeiting and optical temperature measurements for photothermal conversion are further demonstrated. Our architecture design and PL emission tuning results offer many possibilities for constructing multifunctional optical materials by integrating plasmonic and luminescent building blocks into hybrid nanostructures with different configurations.

Eu2+/Ce3+-doped NaAlSiO4 selective occupation-induced emission structure unit evolution and its luminescence characteristics

NaAlSiO4: xEu2+,yCe3+ blue-red phosphors were prepared by high-temperature melting-icy quenching-heat treatment. The effects of emission structure unit evolution, microstrain, microcrystalline size and selective occupation on the luminescence characteristics of the prepared phosphor were systematically studied by powder X-ray diffraction pattern (XRD) and photoluminescence spectroscopy (PL). In the structure of NaAlSiO4: 2%Eu2+, 2%Ce3+ hexagonal crystalline sodium nepheline, Eu2+ ions occupy the Na+ (II) position to form a EuNa+(II)2+ luminescent structure unit, and Ce3+ ions occupy the Na+ (I) position to form a CeNa+(I)3+ luminescent structure unit. The NaAlSiO4: 2%Eu2+/NaAlSiO4: 2%Ce3+ emits 555 nm yellow-green light/395 nm blue-violet light under the excitation of 354 nm/298 nm, respectively, which is derived from the 5d-4f transition of Eu2+ and Ce3+. There is energy transfer of Ce3+→Eu2+ in the sodium nepheline matrix, of which the transport pathway is m EuNa+(II)2+ ←O←n CeNa+(I)3+ →O→m EuNa+(II)2+, and the transport mechanism is electric quadrode-electric quadrupole interaction, and the energy transfer efficiency reaches 98.6%. The sodium nepheline NaAlSiO4: 2%Eu2+, 2%Ce3+ phosphor with energy level barrier 0.386 eV, possesses good thermal stability. This single-phase aluminosilicate multicolor phosphor has potential application value for WLED illumination and PDP display.

Red-Fluorescing Paramagnetic Conjugated Polymer Nanoparticles─Triphenyl Methyl Radicals as Monomers in C–C Cross-Coupling Dispersion Polymerization

We report the synthesis of conjugated polymer nanoparticles carrying stable luminescent radical units. These monodisperse conjugated radical nanoparticles can be tuned in their diameter over several hundred nanometers. They are stable in aqueous medium and highly luminescent in the red and near-infrared spectra, representing a powerful future tool for bioimaging. Moreover, the polymer nanoparticles exhibit paramagnetic properties, making them highly suitable for dual-mode optical and magnetic resonance imaging. In this study, we investigate their synthesis as well as optical and magnetic properties, and use quantum mechanical calculations to elucidate the effect of the conjugated polymer backbone and electron-withdrawing substituents on the electronic properties of the open-shell molecule in the polymer network of the particles.

"Four-In-One" Design of a Hemicyanine-Based Modular Scaffold for High-Contrast Activatable Molecular Afterglow Imaging.

Afterglow luminescence (long persistent luminescence) holds great potential for nonbackground molecular imaging. However, current afterglow probes are mainly nanoparticles, and afterglow imaging systems based on organic small molecules are still lacking and have rarely been reported. Moreover, the lack of reactive sites and a universal molecular scaffold makes it difficult to design activatable afterglow probes. To address these issues, this study reports a novel kind of hemicyanine-based molecule scaffolds with stimuli-responsive afterglow luminescence, which is dependent on an intramolecular cascade photoreaction between 1O2 and the afterglow molecule to store the photoenergy for delayed luminescence after light cessation. As a proof of concept, three modular activatable molecular afterglow probes (MAPs) with a "four-in-one" molecular design by integrating a stimuli-responsive unit, 1O2-generating unit, 1O2-capturing unit, and luminescent unit into one probe are customized for quantification and imaging of targets including pH, superoxide anions, and aminopeptidase. Notably, MAPs show higher sensitivity in afterglow imaging than in fluorescence imaging because the responsive unit simultaneously controls the initiation of fluorescence (S1 to S0) and 1O2 generation (S1 to T1). Finally, MAPs are applied for high-contrast afterglow imaging of drug-induced hepatotoxicity, which is poorly evaluated in clinics and drug discovery. By reporting the sequential occurrence of oxidative stress and upregulation of aminopeptidase, such activatable afterglow probes allow noninvasive imaging of hepatotoxicity earlier than the serological and histology manifestation, indicating their promise for early diagnosis of hepatotoxicity.

Tunable full-color emission phosphors: Enhanced security application via a patterned 3-dimensions code

Developing tunable full-color emission photoluminescent materials is always desired in color-on-demand applications and still confronts challenges. Theoretically, full color including white emission can be achieved by the combination of three primary colors (red, green, and blue) based on the additive color theory. Herein, a strategy for the preparation of tunable full-color luminescence is realized by mixing the inorganic rare-earth-doped SrAl 2 O 4 : Eu 2+ , Dy 3+ (green emission), Y 2 O 2 S: Eu 3+ , Mg 2+ , Ti 4+ , Ti 4+ 0.05 (red emission), and Sr 2 MgSi 2 O 7 : Eu 2+ , Dy 3+ (blue emission) phosphors with different ratios. By adjusting individual phosphors at certain specific ratios, white light (0.332, 0.332) and full-spectra emission are achieved under a single low excitation energy (λ ex = 365 nm) using a portable ultraviolet (UV) lamp. Based on the facile preparation and effective tunable full-color emission features of the phosphors, a novel encryption way of the luminescent unit as information storage 3 dimensions (3D) codes is developed. The multiplexed encrypting information capacity of the codes is enhanced in a 3D maneuver strategy by simply adjusting the number of light-emitting units with infinite emission colors. The proposed strategy makes the tunable full-color emission phosphors useful in promising applications including full-color display, high-level information encryption and anti-fake.

Enhanced excimer fluorescence emission of pyrene derivatives: Applications in artificial light-harvesting systems

Excimer emission usually has a significant Stokes shift, making it an ideal candidate for constructing artificial light-harvesting systems (LHSs). However, the emission of excimers is altered by intermolecular interactions. Precise modulation of the spatial distance and interaction between luminescent units is the key to achieving enhanced emission of excimers. In the current study, electrostatic assembly of polyanionic PSS with cationic bolaamphiphile (PRB) containing pyrene was used to achieve close stacking of pyrene, resulting in significantly enhanced excimer emission. Furthermore, the morphology of the assemblies changed from nanodisks to nanospheres. In particular, the quantum yield of the PRB with PSS increased from 0.5% to 23.1%. In contrast, the amphiphilic molecule containing pyrene with a single hydrophilic head also showed enhanced fluorescence after being co-assembled with PSS. Nevertheless, the fluorescence quantum yield of excimers was much lower than that of the co-assemblies formed with PRB. The assembly formed by PSS and PRB acted as an energy donor. It underwent Förster resonance energy transfer with Nile red, achieving high energy conversion efficiency (ΦET = 49.6%) and antenna effect (9.8) at a donor/acceptor molar ratio of 12.5:1.