Luminescent Polymers Research Articles

Antenna effect enhanced ECL immunoassay using microfloral europium porphyrin coordination polymers based on Eu3+ and TCPP for the detection of chloramphenicol in foods.

The "antenna effect" is one of the most important energy transfer modes in lanthanide light-emitting polymers. In this study, novel luminescent nanostructured coordination polymers (Eu-PCP) were synthesized in one step using Eu3+ as the central metal ion and 5,10,15,20-tetrakis (4-carboxyphenyl) porphyrin (TCPP) as the organic ligand. The unique "antenna effect" observed between Eu3+ and TCPP leads to a substantial improvement in the electrochemiluminescence (ECL) emission efficiency. Eu-PCP exhibits good cathodic ECL characteristics. Additionally, Au@SnS2 nanosheets exhibit favorable electrical conductivity, biocompatibility, and a significant specific surface area. This makes them a suitable choice as substrate materials for the modification of electrode surfaces and capturing antigens. Being well known, the development of sensitive and rapid methods to detect chloramphenicol is essential for food safety. Based on this, we report a novel competitive electrochemiluminescence immunoassay to achieve ultra-sensitive and highly specific detection of chloramphenicol. The linear range was 0.0002-500 ng mL-1 and the detection limit was 0.09 pg mL-1. Apart from that, the experimental results proved that it provided a new analytical tool for the detection of antibiotic residues in food safety.

Synthesis and property modulation of linearly polarized luminescent side-chain polymers with room-temperature phosphorescence

A series of purely organic linearly polarized room-temperature phosphorescent side-chain polymers were successful synthesized using a template-assisted method.

Tunable multicolor fluorescence of polyurethane derivatives controlled by molecular weight

Boron-containing luminescent polymers have been extensively studied for their tunable absorption/emission and excellent light stability.

Thiol-containing hyperbranched polysiloxane for scavenging reactive oxygen species.

Unconventional luminescent polymers have attracted considerable attention in the biological field due to their intrinsic fluorescence properties and excellent biocompatibility. However, exploring the luminescent properties of thiol-containing polymers and the mechanism of their scavenging of ROS remains unclear. In this work, we synthesised three kinds of hyperbranched polysiloxanes (HE, HP, and HB) with terminal thiol groups containing different chain lengths by the polycondensation reaction. Surprisingly, HP exhibits longer-wavelength emission at 480 nm with a quantum yield of 12.23% compared to HE and HB. Experiments and density functional theory (DFT) calculations have revealed that the rigidity of the conformation is enhanced by substantial hydrogen bonds and through-space O⋯O interactions in the polymer structure. These interactions, combined with the rigid carbon chains, balance the flexibility of the Si-O-C chain segments, which emerges as a critical factor contributing to the superior fluorescence performance of HP. In addition, HP exhibits excellent biocompatibility and ROS scavenging ability with a scavenging capacity of up to 35.095%. This work provides a new fluorescent polymer for scavenging ROS for the treatment of ROS-related diseases.

One-pot preparation of nonconventional luminescent polymer gels driven by polymerization

Nonconventional chromophores are good candidates for preparing luminous gels because their luminescence is usually enhanced in the aggregated state.

Zn-coordination polymers for fluorescence sensing various contaminants in water

Luminescent coordination polymers (LCPs) have garnered significant attention from researchers as promising materials for detecting contaminants. In this paper, three new LCPs ([Zn(tib)(opda)]n⋅H2O (1), [Zn3(tib)2(mpda)3]n⋅5H2O (2), [Zn (tib)(ppda)]n⋅H2O (3)) with different structures (LCP 1–3: 1D, 2D, 1D) using phenylenediacetic acid isomers and 1,3,5-tris (1-imidazolyl) benzene (tib) are synthesized. The specific surface areas (BET) of LCP 1–3 are 4 m2/g, 19 m2/g, and 13 m2/g respectively. LCP 1–3 exhibit excellent fluorescence properties and can serve as fluorescent probe for the detection of inorganic contaminants and organic contaminants. Due to the large BET of LCP 2, the detection limits for trace analytes surpass those of LCP 1 and 3. The detection limits of LCP 2 for Fe3+, nitrobenzene (NB), chloramphenicol (CAP), and pyrimethanil (PTH) are 8.3 nM, 0.016 μM, 0.19 μM, and 0.032 μM, respectively, and the fluorescence quenching rates are 98.6 %, 98.8 %, 92.3 %, and 98.8 %, respectively. These values outperform most reported in the literature. The quantum yields of LCP 1–3 are 11.84 %, 25.22 %, 22.00 % respectively. Real sample testing of LCP 1–3 reveals favorable performance, where spiked recoveries of LCP 2 for the detection of pyrimethanil in grape skins ranged from 99.62 % to 119.3 % with a relative standard deviation (RSD) of 0.627 % to 4.56 % (n = 3). The fluorescence quenching mechanism was attributed to a combination of photoelectron transfer (PET), resonance energy transfer (RET), and competitive absorption (CA). This study advances the application of LCPs in luminescence sensing and contributes to the expansion of novel materials for detecting environmental pollutants.

Red-Shifted Luminescence of Acrylonitrile-Containing Copolymers: A Matter of One Methyl Unit.

Copolymerization provides an effective approach to tune the photophysical properties of non-conventional luminescent polymers (NCLPs). In this study, the controlling of intrinsic emissions of polyacrylonitrile (PAN) copolymers is revealed by a delicate difference of secondary monomers. The introduction of methacrylate comonomers can induce a 70-nm red-shifting in the PL emission of copolymers compared with that of acrylate-containing copolymers. The mechanism of such "copolymerization induced red-shifting" in PAN copolymers is investigated. It is demonstrated that the presence of the α-methyl group in the copolymers can enhance the chain rigidity and through-space conjugation (TSC) of C≡N groups, resulting in the red-shifting of emission.

New europium(III) methoxycinnamates complex: synthesis, thermal and luminescence properties

A method was proposed for the preparative synthesis of mixed-ligand Eu(III) compounds with para -methoxycinnamic acid, ligands from the sodium salt of para -methoxycinnamic acid. It was found that europium(III) methoxycinnamate with hexamethylphosphotriamide has the highest luminescence intensity. Luminescent polymer materials with synthesized europium(III) methoxycinnamates were obtained.

Luminescent Europium(III) Compounds with Quinaldic Acid

Heteroligand luminescent europium(III) complexes with quinaldic acid and neutral ligands were prepared. The compounds obtained were characterized by elemental analysis, X-ray diffraction, thermal gravimetric analysis, and IR spectroscopy. The composition of the complexes was determined. In the course of thermolysis, the nitrogen-containing ligand molecule is eliminated in one step with exo- and endothermic effects. The compounds are thermally stable up to 260°С. The synthesized coordination compounds were introduced into low-density polyethylene to obtain luminescent polymer materials.

Synthesis of Hybridized Nontraditional Intrinsic Luminescent Polymers with Ring-Openable Fused Heterocycles by Facile Multicomponent Polymerizations

Synthesis of Hybridized Nontraditional Intrinsic Luminescent Polymers with Ring-Openable Fused Heterocycles by Facile Multicomponent Polymerizations

One-Dimensional Cu(I) coordination polymers with multi-stimuli-responsive luminescence

Luminescent coordination polymers (CPs) with one-dimensional (1D) closely-packed structures usually display poor performances in stimuli-responsive luminescence due to the low porosity and high rigidity. Here, we reported a multi-stimuli-responsive 1D luminescent [Cu2I2]-cluster-based CP (CuIP-OPY) with piezochromic, thermochromic and oxygen sensing properties. Attributing to the flexibility of the OPY ligand, which twists under external forces and heating, respectively, CuIP-OPY shows obvious piezochromic and thermochromic luminescence. Moreover, although its porosity is only 1.1%, oxygen can still quench its luminescence intensity by 57.53%. To further confirm the related mechanism, we also synthesized a [Cu2Cl2]-cluster-based CP with similar structure, namely CuClP-OPY, that displays higher rigidity, and compared the differences between these two CuXP-OPY (X = I, Cl) in the multi-stimuli-responsive behavior.

Multiresponsive luminescent sensors for antibiotics and CrVI with two luminescent ZnII/CdII coordination complexes

Two new ZnII/CdII luminescent coordination polymers (CPs) based on the V-shaped bis(imidazole) ligand 3,6-bis (1H-benzo[d]imidazol-1-yl)-9-methyl-9H-carbazole (bbimc) with [1,1′-biphenyl]-4,4′-dicarboxylic acid ligand (H2bpdc) have been synthesized under solvothermal conditions: {[Zn(bbimc)(bpdc)]·DMF·2.5H2O} (CP 1), {[Cd(bbimc)(bpdc)]·2DMF} (CP 2). CP 1 and CP 2 both display a uninodal 4-c unimodal sql topology 2D framework with vertex symbols of {44·62}. In addition, the two identical 2D nets of CP 2 were interpenetrated each other to form a 2D + 2D → 3D and generate a 2-fold interpenetrating architecture. Moreover, sensing investigations of CP 1 and CP 2 revealed that both of compounds can be used as a highly sensitive and selective multi-responsive luminescent sensor for sensing Cr2O72−, CrO42− and antibiotics (TC: Tetracycline; CTC: Chlortetracycline) in H2O by exhibiting fluorescence quenching with significant quenching constants (Ksv = 1.369 × 104 M−1 (Cr2O72−), 2.003 × 104 M−1 (CrO42−), 5.343 × 104 M−1 (TC), 8.706 × 104 M−1 (CTC) for CP 1 and 4.452 × 104 M−1 (Cr2O72−), 2.119 × 104 M−1 (CrO42−), 4.175 × 104 M−1 (TC), 1.257 × 105 M−1 (CTC) for CP 2). The detection limit are 0.67 μM (Cr2O72−), 0.48 μM (Cr2O72−), 0.23 μM (TC), 0.14 μM (CTC) for CP 1 and 0.28 μM (Cr2O72−), 0.54 μM (CrO42−), 0.31 μM (TC), 0.098 μM (CTC) for CP 2, respectively. In addition, the probable fluorescence quenching mechanism was studied through experiment and theoretical calculation and the co-existance of competitive absorption (CA) and photoinduced electron transfer (PET) progress contributed to such sensing processes.

Hyperbranched Polyborosiloxanes: Non‐traditional Luminescent Polymers with Red Delayed Fluorescence

AbstractNon‐traditional fluorescent polymers have attracted significant attention for their excellent biocompatibility and diverse applications. However, designing and preparing non‐traditional fluorescent polymers that simultaneously possess long emission wavelengths and long fluorescence lifetime remains challenging. In this study, a series of novel hyperbranched polyborosiloxanes (P1–P4) were synthesized. As the electron density increases on the monomer diol, the optimal emission wavelengths of the P1–P4 polymers gradually red‐shift to 510, 570, 575, and 640 nm, respectively. In particular, P4 not only exhibits red emission but also demonstrates delayed fluorescence with a lifetime of 9.73 μs and the lowest critical cluster concentration (1.76 mg/mL). The experimental results and theoretical calculations revealed that the synergistic effect of dual heteroatom‐induced electron delocalization and through‐space O⋅⋅⋅O and O⋅⋅⋅N interaction was the key factor contributing to the red‐light emission with delayed fluorescence. Additionally, these polymers showed excellent potential in dual‐information encryption. This study provides a universal design strategy for the development of unconventional fluorescent polymers with both delayed fluorescence and long‐wavelength emission.

Hyperbranched Polyborosiloxanes: Non-traditional Luminescent Polymers with Red Delayed Fluorescence.

Non-traditional fluorescent polymers have attracted significant attention for their excellent biocompatibility and diverse applications. However, designing and preparing non-traditional fluorescent polymers that simultaneously possess long emission wavelengths and long fluorescence lifetime remains challenging. In this study, a series of novel hyperbranched polyborosiloxanes (P1-P4) were synthesized. As the electron density increases on the monomer diol, the optimal emission wavelengths of the P1-P4 polymers gradually red-shift to 510, 570, 575, and 640 nm, respectively. In particular, P4 not only exhibits red emission but also demonstrates delayed fluorescence with a lifetime of 9.73 μs and the lowest critical cluster concentration (1.76 mg/mL). The experimental results and theoretical calculations revealed that the synergistic effect of dual heteroatom-induced electron delocalization and through-space O⋅⋅⋅O and O⋅⋅⋅N interaction was the key factor contributing to the red-light emission with delayed fluorescence. Additionally, these polymers showed excellent potential in dual-information encryption. This study provides a universal design strategy for the development of unconventional fluorescent polymers with both delayed fluorescence and long-wavelength emission.

A Coordination Polymer for the Fluorescence Turn-On Sensing of Saccharin, 2-Thiazolidinethione-4-carboxylic Acid, and Periodate.

A luminescent 1D coordination polymer (CP) [Zn2L2(H2O)4]·H2O (1, H2L = 1-(4-carboxyphenyl)-1H-pyrazole-3-carboxylic acid) was prepared by a solvothermal method. 1 shows excellent fluorescence properties and has an obvious fluorescence "turn-on" phenomenon for saccharin (SAC), 2-thiazolidinethione-4-carboxylic acid (TTCA), and periodate (IO4-). Between 0 and 60 μM concentration range of SAC, the fluorescence enhancement efficiency (KEC) of 1 reaches 1.00 × 105 M-1 with the limit of detection (LOD) of 90 nM. 1 is the first CP-based sensing material for SAC detection. For TTCA detection, the KEC is 2.73 × 105 M-1 at the 25-80 μM concentration range, and the LOD is 33 nM, the lowest LOD among the sensors that detect TTCA at present. For IO4- ion detection, when the IO4- ion concentration ranges from 0 to 10 μM, the KEC is 2.34 × 105 M-1 and the LOD is as low as 39 nM. In order to better understand the sensing phenomenon, we also discuss in detail the sensing mechanisms for SAC, TTCA, and IO4- ions.

Flexible films of main-chain luminescent liquid crystalline polymers containing renewable biobased bifuran moieties

Luminescent liquid crystalline polymers (LLCPs) have attracted great attention due to their potential applications in liquid crystal display, optical memory storage, organic light-emitting diode, and other fields. However, the fluorescence signals of LLCPs bearing conventional luminophores showing aggregation-caused quenching behavior are strikingly diminished or even vanish in the aggregated state. Herein, we have synthesized three main-chain LLCPs with α-cyanostilbene (CS) and bifuran units connected by different flexible spacer lengths via melt polycondensation. On the one hand, the CS unit acts as a rigid rod-like mesogen with aggregation-induced emission (AIE) characteristics. On the other hand, the renewable biobased bifuran moiety has been chosen because of two main reasons. One is it is a perfect alternative to the rigid fossil-based biphenyl group. The other reason is the addition of bifuran moiety is beneficial for the polycondensation and the extension of the chain length, leading to the enhancement of the toughness of LLCPs. Upon 365 nm UV light irradiation, these polymers undergo an irreversible Z/E isomerization in solution, while the [2 + 2] cycloaddition of CS chromophores occurs in the solid film. Importantly, the polymers display a good film-forming ability, so that the flexible thin films can be achieved by ordinary compression molding. Moreover, the fluorescent patterns can be directly printed on the flexible films on the basis of the [2 + 2] cycloaddition behavior, which shows their promising applications ranging from information storage to high-tech anti-counterfeiting.

Self-healing luminescent polyurethane with ultrahigh toughness resulting from lanthanide-bipyridine segment and hydrogen bonds

Synthesis and manufacturing a new generation of luminescent elastomers that simultaneously features self-healing efficiency with superior mechanical properties remains a challenge due to the compromise between toughness and self-healing ability. Here, a new class of transparent luminescent materials was synthesized via coordinating lanthanide (Ln3+) to bipyridine (Bpy) units introduced into the polymer backbone prepared by polymerization of Polytetramethylene ether glycol (PTMEG) and 4-methylenedicyclohexyl diisocyanate (HMDI). Relying on collaborative reinforcement of a great number of loosely packed Ln3+-ligand coordination bonds and hydrogen bonds (H-bonds), the prepared luminescent polymers showed an ultrahigh toughness of 373.12 MJ m−3 and a mechanical ultrahigh strength of 33.73 MPa. In addition, the multi-color emission behavior of the luminescent materials can be simply adjusted via tailoring the molar ratio of Eu3+/Tb3+. The luminescent self-healing materials can reversibly respond to acid-base vapor because of protonation/deprotonation of Bpy ligands. We believe luminescent polymers obtained by us with excellent mechanical properties and luminescence off/on switching ability show great potential applications as acid-base detector.

Europium(III) diphenylphosphinate as a potential low-dimensional nanostructured coordination polymer scintillator

Rare earth diphenylphosphinates – [RE(dpp)3]n – are low-dimensional nanostructured luminescent materials with considerable thermal and chemical stability, obtained in powder form, consisting of highly insoluble nanowire/nanorod-shaped particles. As a potential candidate for applications as nanocrystalline scintillator devices, [Eu(dpp)3]n has been synthesized by wet route precipitation methodologies. X-ray excited optical luminescence (XEOL) measurements revealed that the samples show intense emission under X-ray excitation, presenting structural and electronic stability against continuous and prolonged exposure to ionizing radiation without changing the chemical environment in which the trivalent europium ion is inserted. Indeed, the self-structuring of [RE(dpp)3]n in a polymeric matrix of high thermal stability allowed [Eu(dpp)3]n to be a low-dimensional nanostructured luminescent coordination polymer resistant to radiation damage.

(Invited) Photoluminescence-Based Circular Polarization Convertors for Multiplexing of Optical Information

Polarized light has a great potential to provide a variety of optical information at once such as light intensity (brightness), wavelength (color), and polarization. In particular, circularly polarized (CP) light is expected to be used not only for 3D display but also for optical data encryption and anti-counterfeiting, because the polarization plane of CP light rotates during light propagation resulting in no angular dependence on information transmission. The previously reported approaches for creating CP light from unpolarized light can be roughly classified into the filtration using a circular polarizer, the selective reflection by chiral liquid crystals, and the circularly polarized luminescence (CPL) from chiral luminophores. Meanwhile, we have recently proposed a new approach for creating highly-pure CP light by converting linearly polarized luminescence (LPL) using luminescence-based CP convertor (Figure 1a).[1] The unique advantage of the luminescence-based CP convertor lies in the spectral conversion properties of the LPL films which allows multiplexing of optical information by simply laminating LPL films. In this presentation, we introduce the multilayer-type luminescence-based CP convertors (Figure 1b) fabricated by using two or three LPL films showing different PL wavelength.In this study, we selected quantum rods (QRs) and π-conjugated luminescent polymers as one-dimensional (1D) luminophores. As a stretchable transparent polymer, poly(ethylene-co-vinyl acetate) (EVA) was used. LPL films were prepared by uniaxial stretching of the luminophore/EVA composite films. When yellow-, orange-, and red-color-emissive QRs were used as a luminophore, yellow-, orange-, and red-LPL were obtained as shown in Figures 1c-e. By laminating LPL film on the quarter-wave film with the angles between polarization plane of LPL and fast-axis of quarter-wave film were -45˚, 0˚, and +45˚, left-handed (LH-), parallel LP, and right-handed (RH-) CP light were produced, respectively. When the yellow-, orange-, and red-LPL films were laminated at three different angles (-45˚, 0˚, and +45˚) against the fast axis of the quarter-wave film, 3×3×3=27 different pieces of optical information were produced as shown in Figure 1f. Furthermore, time information on CP light can also be multiplexed theoretically by laminating several LPL films showing different fluorescence lifetimes. In this presentation, we will also discuss about time-multiplexing of optical information by multilayer-type luminescence-based CP light convertor consisting of multiple LPL films showing different PL lifetimes.[1] Y. Okazaki et. al., J. Mater. Chem. C, 2022. DOI: 10.1039/d2tc03955a. Figure 1

Flexible and luminescent polymer nanocomposite films (YPO4:Pr3+/ polystyrene): Investigation of structural, morphological and photoluminescence properties for solid-state lighting applications

Luminescent polymer films are promising for future optoelectronic devices owing to their ease of synthesis, tunable properties and flexibility. The present work reports on the fabrication of YPO4:Pr3+/polystyrene based flexible and luminescent nanocomposite (NC) films followed by an investigation of their structural, morphological and photoluminescence properties for their potential applications in optical devices. NC films were successfully prepared by direct solution mixing of YPO4: Pr3+ (0.1, 2 at. %) luminescent nanoparticles (NPs) and polystyrene (PS). X-ray diffraction (XRD) analysis of NC films revealed an improvement in crystallinity upon increasing YPO4: Pr3 NPs doping into PS films. The emission spectra of the pure and YPO4:Pr3+/PS NC films under UV excitation at 223 nm showed the same features with a broad emission band in the 280–400 nm region. However, an increase in emission intensity, and absence of interconfigurational emission characteristic of the YPO4: Pr3+ NPs were observed in UV region, due to the strong absorption band of PS in this region. Upon doping, YPO4:Pr3+ NPs were found to reduce their intrinsic luminescence emission from interconfigurational transitions of Pr3+ ions. However, it was dominated by an orange-red luminescence of 1D2→3H4 transition, while, no emission was observed for the PS film owing to its transparency in the visible region. The fluorescence decay times of 1D2→3H4 in the NC films were shorter as compared to those of the original NPs. Chromatic coordinates and correlated color temperature indicated that the YPO4:Pr3+/PS NC films are promising polymer-phosphors for lighting applications.