High Luminescence Research Articles

Highly Efficient Stable Luminescent Radical-Based X-ray Scintillator.

Stable luminescent radicals are open-shell emitters with unique doublet emission characteristics. This feature makes stable luminescent radicals exhibit widespread application prospects in constructing optical, electrical, and magnetic materials. In this work, a stable luminescent radical-based X-ray scintillator of AuPP-1.0 was prepared, which exhibited a high X-ray excited luminescence (XEL) efficiency as well as excellent stability. A mechanism study showed that the heavy atom of Au in AuPP-1.0 endowed it with effective absorption of X-rays, and the doublet emission characteristics of AuPP-1.0 significantly increased its exciton utilization rate in the radioluminescence process. Moreover, AuPP-1.0 has good processability to fabricate a flexible screen for high-quality X-ray imaging, whose resolution can reach 20 LP mm-1. This work demonstrates that the doublet emission is beneficial for improving the exciton utilization rate of radioluminescence, providing a brand-new strategy for the construction of high-performance X-ray scintillators.

Development and Testing of a Glycoengineered Anti-ROR1 Antibody with Enhanced Capacity for Directing Antibody-Dependent Cellular Cytotoxicity (ADCC) of Chronic Lymphocytic Leukemia Cells

Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is an oncoembryonic surface antigen expressed on the neoplastic cells of patients with chronic lymphocytic leukemia (CLL) or other types of cancer, but not on virtually all normal postpartum tissues (Fukuda T., et al., PNAS, 105:3047, 2008). Zilovertamab (also known as UC-961 or cirmtuzumab) is a humanized anti-ROR1 monoclonal antibody (mAb) currently under clinical investigation; this mAb is capable of blocking ROR1-signaling, which can contribute to cancer-cell migration, proliferation, survival, and self-renewal. We generated a glycoengineered form of zilovertamab (GE- zilovertamab) and examined whether it could mediate enhanced antibody-dependent cellular cytotoxicity (ADCC) against neoplastic cells that express ROR1. Initial studies used Jurkat-Lucia™ NFAT-CD16 cells (Invivogen, San Diego, CA, USA) which express high-affinity CD16A (FcγRIIIA, V158 allotype) as effector cells (EC), and the CLL-cell line MEC1, or MEC1 cells transduced to express ROR1 (MEC1-ROR1), as target cells (TC), which each also express CD20. Co-culture of Jurkat-Lucia cells for 6 hours with the anti-CD20 mAb rituximab and MEC1 or MEC1-ROR1 cells induced Jurkat-Lucia cells to express a luciferase reporter gene under the control of an ISG54 minimal promoter fused to six NFAT response elements; this endowed the Jurkat-Lucia cells with high luminescence activity that was not observed in co-cultures of EC and TC without added mAb. Neither zilovertamab nor GE-zilovertamab endowed Jurkat-Lucia cells with higher than background luminescence activity when co-cultured with MEC1 cells. However, GE-zilovertamab could induce high levels of luminescence activity in Jurkat-Lucia cells co-cultured with MEC1-ROR1 cells that was comparable to that of rituximab, and significantly greater than that of zilovertamab. We generated an orthogonal system with which to examine the relative ADCC activity of each of these mAb, using EC generated from the NK cell line, NK92, which we transduced with a lentivirus encoding a newly-generated high-affinity variant of CD16A (CD16v), which has been modified to block its cleavage by ADAM17. NK92 or NK92-CD16v were used as EC to effect cytolysis of Cr 51-labeled MEC1, MEC1-ROR1, or primary CLL cells in a chromium-release assay. Addition of rituximab to co-cultures of EC with Cr 51-labeled MEC1, MEC1-ROR1, or primary CLL caused mAb-dose-dependent ADCC of each of these TC by NK92-CD16v that was significantly greater than that by parental NK92 cells. Again, neither zilovertamab nor GE-zilovertamab could direct ADCC by NK92-CD16v or NK92 ADCC of MEC1 cells, which lack ROR1. However, GE-zilovertamab directed dose-dependent ADCC of MEC1-ROR1 or primary ROR1 + CLL cells by either NK92-CD16v or NK92 at levels comparable to that directed by rituximab for either EC population; such levels were significantly greater than that directed by zilovertamab. ROR1 + CLL cells harboring del(17p) or mutations in TP53 (del(17p)/m TP53) and/or that were resistant to targeted therapies (e.g., inhibitors of BTK or BCL2), were as susceptible to GE-zilovertamab-directed ADCC as were CLL cells without del(17p)/m TP53 from patients who had not had prior therapy. These data demonstrate that GE-zilovertamab can direct high-level ADCC lysis of ROR1-expressing neoplastic cells with greater activity than zilovertamab, encouraging development of clinical studies to evaluate GE-zilovertamab for therapy of patients with CLL or other ROR1-positive cancers.

Detection and sorption of heavy metal ions in aqueous media using Zn-based luminescent metal-organic framework

In this study, we present the synthesis and comprehensive characterisation of a novel, luminescent Metal-Organic Framework (MOF) denoted as PUC7, derived from Zn(NO3)2·6H2O, 1,2-di(4-pyridyl)ethylene, and 2-amino-terephthalic acid through solvothermal method. The PUC7 was successfully characterised using many techniques, including single crystal X-ray diffraction, powder X-ray diffraction, FTIR spectroscopy, BET surface area analysis, FESEM imaging, XPS, UV–visible spectroscopy, and zeta potential measurements. Remarkably, PUC7 exhibited high luminescence properties and water stability. The luminescence properties were utilised for the detection of heavy metal ions. Consequently, PUC7 displayed exceptional selectivity and sensitivity towards W6+ and V5+, with impressively low detection limits of 0.17 μM and 0.22 μM, along with high quenching constant values of 2.5 × 105 M−1 and 1.1 × 105 M−1, respectively. Additionally, we explored PUC7′s proficiency in removing W6+ and V5+ ions from aqueous solution, revealing maximum adsorption efficiencies of 476.2 mg/g and 460.8 mg/g, respectively, fitting well with the Langmuir adsorption model and exhibiting second-order kinetics. Encouragingly, PUC7 demonstrated reusability for up to five cycles in removing W6+ and V5+ ions. Altogether, this research underscores the potential of PUC7 as a versatile and promising tool for efficiently detecting and removing W6+ and V5+ ions from water, with implications for environmental remediation and water purification applications.

A multifunctional emitter with synergistical adjustment of rigidity and flexibility for high-performance data-recording and organic light-emitting devices with “hot exciton” channel

An intramolecular dual-locking design is proposed for organic luminescent materials, aiming at synergistically adjusting the molecular rigidity and flexibility for applications in data storage and light-emitting devices. According to this concept, a multifunctional donor–acceptor type emitter, LPCz-TRZ, is developed, featuring a “soft” diphenylmethane lock and a “hard” single-bond lock in its donor moiety. The highly locked structure results in appreciable rigidity that endows LPCz-TRZ with high luminescence efficiency, narrow emission, promoted charge conductivity and triplet harvesting “hot exciton” channels, allowing high-performance deep-blue organic light-emitting diodes (OLEDs) with an external quantum efficiency as high as 7.88%, which is among the best deep-blue “hot exciton” OLEDs. Notably, the structure of LPCz-TRZ is semi-flexible, leading to unique mechanochromic luminescence (MCL) behavior. Compared to the conventional MCL emitters, the orchestration of rigidity and flexibility in LPCz-TRZ affords high-contrast, fatigue-resistance MCL, as evidenced by a simple, rewritable data-recording demonstration with negligible fatigue after up to 15 wiring-erasing cycles.

Excitation Wavelength‐Dependent Fluorescence of a Lanthanide Organic Metal Halide Cluster for Anti‐Counterfeiting Applications

AbstractThe achievement of significant photoluminescence (PL) in lanthanide ions (Ln3+) has primarily relied on host sensitization, where energy is transferred from the excited host material to the Ln3+ ions. However, this luminous mechanism involves only one optical antenna, namely the host material, which limits the accessibility of excitation wavelength‐dependent (Ex‐De) PL. Consequently, the wider application of Ln3+ ions in light‐emitting devices is hindered. In this study, we present an organic–inorganic compound, (DMA)4LnCl7 (DMA+=[CH3NH2CH3]+, Ln3+=Ce3+, Tb3+), which serves as an independent host lattice material for efficient Ex‐De emission by doping it with trivalent antimony (Sb3+). The pristine (DMA)4LnCl7 compounds exhibit high luminescence, maintaining the characteristic sharp emission bands of Ln3+ and demonstrating a high PL quantum yield of 90–100 %. Upon Sb3+ doping, the compound exhibits noticeable Ex‐De emission with switchable colors. Through a detailed spectral study, we observe that the prominent energy transfer process observed in traditional host‐sensitized systems is absent in these materials. Instead, they exhibit two independent emission centers from Ln3+ and Sb3+, each displaying distinct features in luminous color and radiative lifetime. These findings open up new possibilities for designing Ex‐De emitters based on Ln3+ ions.

Double Gain of Efficient UV‐C Phosphor and Fast Scintillator Based on Pr3+‐doped KY3F10 Nano‐Glass Composites

AbstractGlassy phosphors offer a promising opportunity to overcome the limits of polycrystalline counterparts, thanks to their merits including excellent optical transparency, abandonment of organic binders, and capability of drawing fibers, etc. However, research and development of glassy UV‐C phosphors and fast scintillators have seriously lagged behind crystals. Here, a new type of efficient UV‐C phosphors and fast scintillators (double gain) is developed from Pr3+‐doped transparent nano‐glass composites (nano‐GCs) containing KY3F10 nanocrystals. Such a material combines favorably the advantages of both crystal and glass, exhibiting intense interconfigurational 5d‐4f emissions of Pr3+ upon deep‐UV, high energy electron‐beam and X‐ray excitations. The emission profile ideally overlaps with the germicidal effectiveness curve. The Pr3+‐doped nano‐GCs are endowed with a radiative decay time shorter than that of extensively studied Ce3+‐doped glasses and nano‐GCs. They exhibit intense X‐ray excited radioluminescence that is comparable to the standard Bi4Ge3O12 (BGO) crystal and significantly stronger than Pr3+‐doped ZBLAN fluoride glass known for the high luminescence efficiency. An X‐ray imaging system with a good spatial resolution using the Pr3+‐doped nano‐GCs is also demonstrated.

All-Inorganic Green Synthesis of Small-Sized and Efficient K2SiF6:Mn4+ Phosphor for Mini-LED Displays.

High-resolution liquid crystal display (LCD) backlight requires a color conversion layer featuring micrometer light-emitting particles and a uniform morphology. The widely used commercial red-emitting K2SiF6:Mn4+ phosphor, showing promise as a light-conversion candidate, faces limitations due to its toxic synthesis process, large particle size, and poor moisture resistance. We successfully demonstrated an efficient substitution of the highly toxic HF/TEOS/KHF2 solvent system with a commonly used HCl/SiO2/KF solvent system to synthesize the small-sized K2SiF6:Mn4+ phosphor. Additionally, surface passivation was performed to enhance the luminescence intensity and resistance to moisture, denoted as K2SiF6:Mn4+@CaF2. Accordingly, the K2SiF6:Mn4+@CaF2 phosphor presents a high luminescence efficiency (99.87%/32.84% IQE/EQE) with an average particle size of ∼2.67 μm. Notably, after exposure to 85% humidity and 85 °C temperature for 3 h, the luminescence intensity remains at 47.4% for K2SiF6:Mn4+@CaF2, while 21.2% for pristine K2SiF6:Mn4+, and only 3.5% for K2SiF6:Mn4+ synthesized by TEOS. These advancements hold great potential for improving high-resolution LCD backlighting, particularly for displays with micron-level pixels, opening up new possibilities for enhanced display technology.

Surface motifs regulated aggregation induced emission in AuAg nanoclusters combined with Ce(III)/Ce(IV) catalytic cyclic amplification strategy for sensitive bioanalysis

Achieving high luminescence intensity in electrochemiluminescence biosensors is a challenge for metal nanoclusters (MNCs) due to their non-radiative relaxation-mediated self-quenching tendency. Here, the surface motifs [M(I)-SR] of MNCs were regulated based on aggregation-induced emission (AIE) strategy was proposed to mitigate non-radiative relaxation vibrations, and an efficient luminescent AuAg NCs was designed via host-guest assembly as a signal probe. The Au(I)-SR of AuAg NCs used glutathione (GSH) as a template and reducing agent, and the introduction of Ag(I) made the Au(I)-SR of AuAg NCs cross-linked and interlocked, resulting in AuAg NCs with denser surface patterns. The aggregation of surface motifs limited the ligand movement to reduce the non-radiative energy dissipation. Furthermore, the spontaneous catalytic cycle amplification strategy of Ce(III)/Ce(IV) redox pairs in the matrix material of Ce-MOF promoted the reaction of more co-reactants triethylamine (TEA), obtaining potent reducing radicals TEA* for further improving the ECL efficiency of AuAg NCs. Using cardiac troponin I (cTnI) as the analytical model, the biosensor exhibited a wide linear relationship range (50 fg·mL−1 - 500 ng·mL−1) and a low detection limit (4.77 fg·mL−1). The breakthrough in surface motifs regulation of MNCs guides a new way to design high luminiferous MNCs, and further expands the application potential of MNCs.

Sb-Doped Cs3 TbCl6 Nanocrystals for Highly Efficient Narrow-Band Green Emission and X-Ray Imaging.

Metal halide nanocrystals (NCs) with high photoluminescence quantum yield (PLQY) are desirable for lighting, display, and X-ray detection. Herein, the novel lanthanide-based halide NCs are committed to designing and optimizing the optical and scintillating properties, so as to unravel the PL origin, exciton dynamics, and optoelectronic applications. Sb-doped zero-dimensional (0D) Cs3 TbCl6 NCs exhibit a green emission with a narrow full width of half maximum of 8.6nm, and the best PLQY of 48.1% is about three times higher than that of undoped NCs. Experiments and theoretical calculations indicate that 0D crystalline and electronic structures make the exciton highly localized on [TbCl6 ]3- octahedron, which boosts the Cl- -Tb3+ charge transfer process, thus resulting in bright Tb3+ emission. More importantly, the introduction of Sb3+ not only facilitates the photon absorption transition, but also builds an effective thermally boosting energy transfer channel assisted by [SbCl6 ]3- -induced self-trapped state, which is responsible for the PL enhancement. The high luminescence efficiency and negligible self-absorption of the Cs3 TbCl6 : Sb nanoscintillator enable a more sensitive X-ray detection response compared with undoped sample. The study opens a new perspective to deeply understand the excited state dynamics of metal halide NCs, which helps to design high-performance luminescent lanthanide-based nanomaterials.

Time-resolved excited-state dynamics of star-shaped carbazole-based room temperature phosphorescent molecule by ultrafast absorption spectroscopy

Star-shaped room-temperature phosphorescent (RTP) molecules have attracted much attention due to high luminescence efficiency by inhibiting nonradiative transition of triplet excitons. In this work, the photophysical processes of 1,3,5-tri(9h-carbazol-9-phenyl)benzene (TCzP) and tri(4-carbazol-9-phenyl)amine (TCzTa), with benzene and triphenylamine (TPA) as central cores respectively and carbazole (Cz) as peripheral groups, are investigated. The excited state absorption (ESA) signal (625 nm) of TCzP reaches maximum intensity within 8.8 ps in the femtosecond (fs) transient absorption (TA) spectroscopy and then decays significantly with the enhancing of triplet-triplet absorption (TTA) signal (425 nm). These evolution processes of spectral signal and the appearance of isosbestic point at 450 nm together confirm the intersystem crossing (ISC) process within 5.1 ns. The TTA signal gradually disappears in the nanosecond (ns) TA spectroscopy with a phosphorescence lifetime (τph) of 2 μs. Compared to TCzP, TCzTa exhibits similar spectral evolution behavior with faster ISC of 2.1 ns and lower τph of 0.95 μs. The theoretical simulation shows that the nitrogen atoms in the TPA core of TCzTa leads to a significantly increased spin-orbit coupling constant of S1→Tn (0.86 cm−1) and T1→S0 (0.08 cm−1) than that of TCzP (0.25 cm−1 and 0.05 cm−1), resulting in the shorter experimental ISC rate constants (2.1 ns) and τph (0.95 μs). This work provides reasonable insights for understanding the real-time spectral signal evolution of star-shaped carbazole-based RTP molecules.

The developments of cyan emitting phosphors to fulfill the cyan emission gap of white-LEDs.

Future generations of solid-state lighting (SSL) will prioritize the development of innovative luminescent materials with superior characteristics. The phosphors converted into white light-emitting diodes (white LEDs) often have a blue-green cavity. Cyan-emitting phosphor fills the spectral gap and produces "full-visible-spectrum lighting." Full-visible spectrum lighting is beneficial for several purposes, such as light therapy, plant growth, and promoting an active and healthy lifestyle. The design of cyan garnet-type phosphors, like Ca2LuHf2Al3O12 (CLHAO), has recently been the subject of interest. This review study reports a useful cyan-emitting phosphor based on CLHAO composition with a garnet structure to have a cyan-to-green emitting color with good energy transfer. It could be employed as cyan filler in warm-white LED manufacturing. Due to its stability, ability to dope with various ions suitable for their desired qualities, and ease of synthesis, this garnet-like compound is a great host material for rare-earth ions. The development of CLHAO cyan-emitting phosphors has exceptionally high luminescence, resulting in high CRI and warm-white LEDs, making them a viable desire for LED manufacturing. The development of CLHAO cyan-emitting phosphors with diverse synthesis techniques, along with their properties and applications in white LEDs, are extensively covered in this review paper.

Optical properties of Cs2NaTlBr6 double perovskite using GW correction and Bethe-Salpeter equation

To avoid the toxicity of organic-inorganic perovskites, including Tl, environmentally-friendly double perovskites have drawn much attention recently due to their stability compared to normal perovskites. Despite its favorable gap, there is insufficient research on the double perovskite Cs2NaTlBr6, and its photoelectric properties are still unclear. This work investigated the electronic band structure and optical absorption spectrum of Cs2NaTlBr6 based on the excitonic effect using density functional theory, GW, and Bethe-Salpeter equation (BSE) correction. GW method, by considering the electron-hole interaction, combined with the BSE derived from two-particle Green’s function, is an accurate approach to studying the optical properties and excitonic effects. The results show that BSE correction significantly affects the optical absorption spectrum. It turns out that there is a high bounded dark exciton before the first bright one. The first bright excitons are strongly localized and have a strong binding energy. This high binding energy can cause high luminescence in light-emitting devices.

Multiple lattice sites occupied AlTaO4:Cr3+ phosphor for luminescence ratiometric thermometry and NIR light source

Cr3+-doped near infrared (NIR) phosphors have promising applications in NIR light sources and optical temperature detection. The development of materials with high relative sensitivity and efficient broadband NIR luminescence is the key. In this paper, we report a new multifunctional NIR phosphor AlTaO4:Cr3+, which contains both narrow-band emission associated with 2Eg→4A2 g transition and broadband emission induced by the 4T2 g→4A2 g transition owing to Cr3+ occupies both AlO6 and TaO6 lattice sites. The R-line (2Eg→4A2 g) emission and its anti-Stokes phonon sideband emission follow the Boltzmann distribution, and the thermometer constructed accordingly reaches a maximum Sr of 1% K−1 at 110 K. Under 425 nm excitation, the broad emission band (FWHM = 200 nm) reaches maximum at 880 nm with an internal quantum efficiency of 62.8%. The NIR LEDs prepared with AlTaO4:Cr3+ confirm the application value in NIR light sources.

Modulation of optical oxygen sensitivity of H2(TPP) by using Eu3+, Gd3+ and Yb3+ ions doped silicate-based bioactive glass powders immersed in simulated body fluid

Improving the performance of optical oxygen sensors can be accomplished by adding additives to the composition comprising an oxygen-sensitive probe encapsulated in a polymeric matrix. In this study, to advance the oxygen sensing ability, free meso-tetraphenyl porphyrin (H2(TPP)) was chosen as a luminophore. The sol-gel based 13–93 bioactive glass powders (BG) co-doped with ytterbium (Yb3+), gadolinium (Gd3+), and europium (Eu3+) and immersed in simulated body fluids (SBF) were also used as additives. After being immersed in SBF, bioactive glasses containing Eu3+, Gd3+, and Yb3+ were found to be able to convert hydroxyapatite corresponding to in vitro bioactivity tests. The optimum additive concentration for all glass samples is 3 wt%, based on photoluminescence-based properties. The luminescence dye was incorporated into poly(trimethylsilylpropyne) [poly(TMSP)] matrices in the form of a thin film along with bioactive glass additives to improve oxygen sensitivity. Emission-based intensity values of all porphyrin complexes have been followed as a signal drop during oxygen sensing measurements. The H2(TPP) along with the additive of BG:Eu3+ showed a 6.88 fold of I0/I ratio compared to the undoped and Gd3+ and Yb3+-doped BG forms in terms of the relative signal change. Large Stoke's shift (Ksv) values, high luminescence abilities, and linear spectral response make them promising candidates as oxygen sensing agents. It was concluded that prepared bioactive glass powders are suitable to use as additive materials for improving the oxygen sensitivity of meso-tetraphenyl porphyrin dye.

Energy transfer of Eu2+→Eu3+ improves the photoluminescence properties of orange-red phosphor La2O2S:Eu

Red phosphor with excellent performance plays an important role in improving the luminous performance of white LED(w-LEDs). In this work, a novel type of orange-red phosphors La2-xO2S:xEu(2+,3+) (0.01 ≤ x ≤ 0.08, ∆x = 0.01) for white LED were synthesized via high-temperature solid-state method, and the phase, morphology, luminescent properties, and thermal stability of the samples were systematically studied. The samples all belong to hexagonal crystal system, and the space group are all P-3m1 (164). Through XPS analysis, it was found that Eu2+ and Eu3+ coexist in La1.96O2S:0.04Eu(2+,3+) phosphor. The energy transfer between Eu2+ and Eu3+ was realized, and the fluorescence intensity increased by 418.03 %. The optimal doping concentration of Eu ions in La2-xO2S:xEu(2+,3+) phosphors is x = 0.04, and the concentration quenching mechanism is the electric quadrupole electric quadrupole (q-q) interaction. La1.96O2S:0.04Eu(2+,3+) phosphor has excellent thermal stability，the fluorescence intensity still remains 82.67 % at 418 K compared with room temperature, the activation energy Ea= 0.3961 eV, and the trap theory was used to explain the mechanism of thermal quenching. La1.96O2S:0.04Eu(2+,3+) phosphor has high luminescence quality with color purity of 87.08 %. These results show that La1.96O2S:0.04Eu(2+,3+) phosphor has certain application value in the field of white LED phosphors.

A mechanoluminescent material, ZnS:Mn,Li, with enhanced brightness for visualizing dental occlusion.

Mechanoluminescent materials are characterized by high luminescence intensity, high repeatability, no external voltage activation, and a good linear relationship between stress and mechanoluminescence intensity within a certain range. Therefore, mechanoluminescent materials have attracted increasing attention from researchers in the fields of stress sensing, encryption and anti-counterfeiting, structural health monitoring, energy-saving lighting, intelligent wearable devices, and other fields. In this study, ZnS:Mn powders with different Mn2+ ratios and different ion doping were synthesized by a high-temperature solid-phase reaction, and the synthesis of various materials was characterized. Then, the optimal mechanoluminescence effect of the ZnS:1%Mn,1%Li materialwas obtained. The photoluminescence intensity of ZnS:1%Mn,1%Li was 16.7 times higher than that of the sample without doping with Li+, and the mechanoluminescence intensity was 1.64 times higher. Finally, polyethylene terephthalate (PET) film was combined with ZnS:Mn,Li mechanoluminescent powders to prepare flexible three-layer composite film. Based on this, a feasible strategy for the detection of temporomandibular disorders was proposed. The composite film is easy to use, economical, and safe, and has good mechanoluminescent performance, which has potential application value in the field of occlusal force detection and visualization.

Internalization of Pegylated Er:Y2O3 Nanoparticles inside HCT-116 Cancer Cells: Implications for Imaging and Drug Delivery.

Lanthanide-doped nanoparticles, featuring sharp emission peaks with narrow bandwidth, exhibit high downconversion luminescence intensity, making them highly valuable in the fields of bioimaging and drug delivery. High-crystallinity Y2O3 nanoparticles (NPs) doped with Er3+ ions were functionalized by using a pegylation procedure to confer water solubility and biocompatibility. The NPs were thoroughly characterized using transmission electron microscopy (TEM), inductively coupled plasma mass spectrometry (ICP-MS), and photoluminescence measurements. The pegylated nanoparticles were studied both from a toxicological perspective and to demonstrate their internalization within HCT-116 cancer cells. Cell viability tests allowed for the identification of the "optimal" concentration, which yields a detectable fluorescence signal without being toxic to the cells. The internalization process was investigated using a combined approach involving confocal microscopy and ICP-MS. The obtained data clearly indicate the efficient internalization of NPs into the cells with emission intensity showing a strong correlation with the concentrations of nanoparticles delivered to the cells. Overall, this research contributes significantly to the fields of nanotechnology and biomedical research, with noteworthy implications for imaging and drug delivery applications.

NIR FRET Luminescence in Rhenium Complex and Dye Co‐Loaded Polymer Nanoparticles

AbstractPhotoactive transition‐metal complexes are luminophores combining high photostability and long luminescence lifetimes. However, reduced optical performance in aqueous solutions has limited their use in biological systems. Herein, the physicochemical and photophysical properties and bioimaging compatibility of Re diimine complexes and near‐infrared (NIR) emitting Cy5 dyes coencapsulated in polymer nanoparticles (NPs) are investigated. By varying the polymers, NPs with sizes from 20 to 70 nm and encapsulating ≤ 40 wt.% of Re complexes, i.e., ≈11 000 Re complexes per NP, are obtained. The photoluminescence (PL) quantum yields of the Re complexes increase eightfold to ≈50% upon encapsulation (vs 6–7% in acetonitrile), resulting in PL brightness up to 108 m−1 cm−1 and PL lifetimes of 3–4 µs. Coencapsulation of Cy5 yields very bright NIR emission upon Re complex excitation. Very close Re‐to‐Cy5 donor–acceptor distances down to ≤2 nm and FRET efficiencies over 90% are confirmed by PL lifetime measurements. The Re‐Cy5 NPs enter mammalian cells for high‐contrast PL imaging in both visible and NIR. This detailed characterization provides a better understanding of the photophysical properties of the transition‐metal‐dye FRET NPs and presents a vital step toward the efficient design of a new class of bright luminescent NP probes.

Recyclable soft photonic crystal film with overall improved circularly polarized luminescence

Existing circularly polarized luminescence materials can hardly satisfy the requirements of both large luminescence dissymmetry factor and high luminescent quantum yield, which hinders their practical applications. Here, we present a soft photonic crystal film embedded with chiral nanopores that possesses excellent circularly polarized luminescence performance with a high luminescence dissymmetry factor as well as a large luminescent quantum yield when loaded with various luminescent dyes. Benefitting from the retention of chiral nanopores imprinted from a chiral liquid crystal arrangement, the chiral soft photonic crystal film can not only endow dyes with chiral properties, but also effectively avoid severe aggregation of guest dye molecules. More importantly, the soft photonic crystal film can be recycled many times by loading and eluting guest dye molecules while retaining good stability as well as circularly polarized luminescence performance, enabling various applications, including smart windows, multi-color circularly polarized luminescence and anticounterfeiting.

A rational strategy for directly synthesizing strongly yellow solid-state fluorescent-emitting carbon nanodots composite microparticles by structure regulation

Carbon nanodots (CDs) have received huge attention of researchers due to their good optical properties. However, CDs generally suffer from severely fluorescence self-quenching once they are aggregated or in solid state, limitating their applications in light-emitting devices. In this work, we report a rational strategy for synthesis of yellow fluorescent carbon nanodots (Y-CDs)-based microparticles with a high solid-state photoluminescence quantum yield (32.02%). It is the first report on designing a lamellar structured matrix to disperse CDs to realize long-wavelength solid fluorescence. The matrix is confirmed as p-phenylenediamine dihydrochloride by X-ray diffraction (XRD). 3-glycidyloxypropyltrimethoxysilane (KH-560) acts as a bridge to connect CDs to the matrix based on epoxy-amine reaction and silane hydrolysis condensation for uniform dispersion of CDs and high solid-state luminescence can be easily achieved. Meanwhile, through adjusting the amount of KH-560, the morphology of Y-CDs-based microparticles can be controlled from cube to layered structure and the fluorescence intensity can be significantly improved. Importantly, the optimal Y-CDs particles can be combined with blue chips (450 nm) to fabricate high-performance white light-emitting diodes (WLEDs) without using commercial phosphor, and the constructed WLEDs exhibit a high color rendering index (CRI) of 84.2.