Afterglow Emission Research Articles

Development of smart adhesive using lanthanide-doped phosphor and carboxymethyl cellulose-reinforced gum Arabic

Smart polymer glue with photoluminescence and water-repellent properties was developed. The luminescent adhesive continues emitting light for up to 120 min after turning the excitation source off. Nanoparticles of lanthanide strontium aluminum oxide (LSAO) (8–13 nm) were consistently immobilized into carboxymethyl cellulose-reinforced gum Arabic (CMC/GA) adhesive. Using various concentrations of LSAO, the generated adhesives showed emission intensity at 519 nm and an excitation band at 365 nm. Depending on LSAO content, both of afterglow and fluorescence emission were monitored. Photochromism was detected as the transparent adhesive film changes color to green under ultraviolet irradiation. A greenish-yellow lightening in a darkened place was also observed. The nanocomposite resistance to scratches and hydrophobicity were found to enhance as the LSAO content was increased in the carboxymethyl cellulose-reinforced gum Arabic matrix. The LSAO@CMC/GA nanocomposite showed high durability and photostability. The present strategy proved the viability of a potential mass production toward photoluminescent adhesives for various smart applications, such as smart packaging, anti-counterfeiting printing, smart windows, and safety signs.

Achieving Colorful Ultralong-Lifetime Room-Temperature Phosphorescence Based on Benzocarbazole Derivatives through Resonance Energy Transfer.

It is of practical significance to develop polymer-based room-temperature phosphorescence (RTP) materials with ultralong lifetime and multicolor afterglow. Herein, the benzocarbazole derivatives were selected and combined with a poly(vinyl alcohol) (PVA) matrix by a coassembly strategy. Owing to the hydrogen-bonding interactions between benzocarbazole derivatives and the PVA matrix, the nonradiative transition and the quenching of triplet excitons are effectively inhibited. Therefore, the maximum phosphorescence emission lifetime of 2202.17 ms from ABfCz-PVA and the maximum phosphorescence quantum efficiency of 34.97% from ABtCz-PVA were obtained, respectively. In addition, commercially available dye molecules were selected to construct phosphorescent resonance energy transfer (PRET) systems for energy acceptors, enabling full-color afterglow emission in blue, green, yellow, red, and even white. Based on the characteristics of prepared RTP materials, multifunctional applications to flexibility, information encryption, and erasable drawing were deeply explored.

Super long ultraviolet-A persistent luminescence and photo-stimulated luminescence from CaMgGeO4: Bi3+

Here, we have developed a novel ultra long ultraviolet-A afterglow material CaMgGeO4: Bi3+, which shows more than 24 h UVA afterglow emission peaked at 346 nm. The crystal structure shows that the prepared sample is a pure phase with an orthogonal system of Pmnb space group. The composition of valence band and conduction band was analyzed by the density of states, which reveals that the bandgap of the CaMgGeO4 matrix is 3.69 eV. The photoluminescence spectrum of the sample consists of a broadband in the 320–400 nm UVA region, which belongs to the 3P1 → 1S0 electron transition of Bi3+. More importantly, under the excitation of ultraviolet lamp for 3 min, CaMgGeO4: Bi3+ exhibited an UVA ultra long persistent luminescence (LPL) with a duration of more than 24 h, which afterglow emission intensity still reaches 1500 cps and is about 6 times of the background intensity. In addition, the UVA emission of CaMgGeO4: Bi3+ after 13 h day can be repeatedly by short periods of low-energy light sources stimulation. The thermoluminescence analysis indicates that the presence of shallow and deep traps is responsible for excellent UVA-LPL and photo-stimulate luminescence (PSL). The excellent LPL and PSL properties can prompt CaMgGeO4: Bi3+ phosphor to be widely used in the field of photodynamic therapy.

Probing Electromagnetic Gravitational-wave Emission Coincidence in a Type I Binary-driven Hypernova Family of Long Gamma-Ray Bursts at Very High Redshift

The repointing time of the X-Ray Telescope (XRT) instrument on the Neil Gehrels Swift Observatory satellite has posed challenges in observing and studying the early X-ray emissions within ≈40 s after a gamma-ray burst (GRB) trigger. To address this issue, we adopt a novel approach that capitalizes on the cosmological time dilation in GRBs with redshifts ranging from 3 to 9. Applying this strategy to Swift/XRT data, we investigate the earliest X-ray emissions of 368 GRBs from the Swift catalog, including short and long GRBs. We compare the observed time delay between the GRB trigger and the initial Swift/XRT observation, measured in the GRB observer frame, and the corresponding cosmological rest-frame time delay (RTD). This technique is here used in the analysis of GRB 090423 at z = 8.233 (RTD ∼8.2 s), GRB 090429B at z ≈ 9.4 (RTD ∼10.1 s), and GRB 220101A at z = 4.61 (RTD ∼14.4 s). The cosmological time dilation enables us to observe the very early X-ray afterglow emission in these three GRBs. We thus validate the observation of the collapse of the carbon–oxygen core and the coeval newborn neutron star (νNS) formation triggering the GRB event in the binary-driven hypernova (BdHN) scenario. We also evidence the νNS spin-up due to supernova ejecta fallback and its subsequent slowing down due to the X-ray/optical/radio synchrotron afterglow emission. A brief gravitational-wave signal may separate the two stages owing to a fast-spinning νNS triaxial-to-axisymmetric transition. We also analyze the long GRB redshift distribution for the different BdHN types and infer that BdHNe II and III may originate the NS binary progenitors of short GRBs.

Multiple immobilized borate composites achieving Color-Tunable long afterglow in aqueous media for bioimaging and anti-counterfeiting

The afterglow phenomenon has garnered significant attention due to its exceptional luminescent properties, yet achieving long-lived and color-tunable afterglow in aqueous media remains a challenging task. In this article, we present a facile hydrothermal strategy for the preparation of borate afterglow materials (APB@CC) using ammonium pentaborate and cyanuric chloride as starting materials. The resultant APB@CC displays color-tunable long afterglows from blue to green in aqueous media. Further studies show that the synergistic effect of covalent and hydrogen bonds effectively promotes the immobilization and rigidification of the triplet state, enabling afterglow emission in aqueous media. Encouraged by color-tunability in solutions, we implemented their potential applications in bioimaging and anti-counterfeiting. This work not only provides insights for extending borate afterglow materials in aqueous media, but also will facilitate the development of high signal-to-noise bioimaging and advanced anti-counterfeiting techniques.

A novel visible light excited room temperature afterglow luminescent carbon dots/boric acid composite for information encryption and Fe3+ sensing

Visible light excited room temperature afterglow luminescent carbon dots are rare and most of them are excited by ultraviolet light, which has potential phototoxicity, and the quantum yield of afterglow is always low. This article reports a novel room temperature afterglow luminescent carbon dots/boric acid composite (BCDs composite) that can be excited by visible light such as 450 nm LED light, flashlight, and even mobile phone flashlight with high afterglow quantum yield of 48.4 % and long afterglow lifetime of 866 ms. Based on their excellent afterglow emission property, they can be applied for information security under humidity stimulation. Under daily storage condition, the information written by BCDs composite has no afterglow, and when dried with a hair dryer, the information was lighted by afterglow. Meanwhile, the BCDs composite can also be used for highly sensitivity Fe3+ sensing with a low detection limit of 102 nM in Tris-HCl buffer. This study not only successfully developed a novel room temperature long afterglow luminescent carbon dot based nanomaterial with multiple uses and visible light excitation, but also may provide ideas for the design of subsequent room temperature afterglow carbon dots and carbon dot based sensing probes.

Photoluminescent polypropylene nanofiber-supported polyethylene terephthalate integrated with strontium aluminate phosphor

In order to develop photochromic materials with persistent afterglow emission, such as concrete and smart windows, electrospun polypropylene nanofibers (PPNF) were incorporated into polyethylene terephthalate (PET) for reinforcement. Nanoparticles of lanthanide-activated strontium aluminum oxide (NLSA) were physically embedded into polyethylene terephthalate films to produce transparent PPNF@PET smart membranes. Electrospinning was utilized to create PPNF, which were subsequently included as a roughening agent into PET membranes. The green coloration detected upon exposing the PPNF@PET film to ultraviolet light was verified by CIE Lab coordinates and photoluminescence analysis. The PPNF@PET hybrids with low quantities of NLSA were found to immediately reverse this emission activity after removing the ultraviolet source, which suggest fluorescence emission. Afterglow photoluminescence was detected at higher phosphor concentrations in PPNF@PET by slow reversibility of the light emission, which suggests glow in the dark emission. After 365 nm of excitation, a 517 nm emission band could be monitored from the PPNF@PET hybrids. The chemical structure and morphology of LSA nanoparticles and PPNF were studied, showing diameters of 80–120 nm and 75–180 nm, respectively. Different analysis methods were employed to examine the morphologies of PPNF@PET membranes. As compared to a NLSA-free polyethylene terephthalate control sample, the PPNF@PET smart membranes demonstrated improved scratch resistance. The hydrophobicity and UV resistance of the PPNF@PET smart membranes were improved with an increase in the concentration of NLSA.

Preparation of polypropylene nanofibers reinforced multifunctional epoxy composite concrete with ultraviolet‐driven afterglow emission

AbstractIn order to develop smart concrete with afterglow emission, epoxy resin (EPX) was immobilized with nanoparticles of alkaline earth aluminate (NAEA) as a photoluminescent agent and electrospun polypropylene nanofibers (EPN) as a reinforcement agent. Scanning electron microscope images of EPN displayed diameters of 70–90 nm, whereas transmission electron microscopic images showed that NAEA has diameters of 3–9 nm. To create a transparent sheet that glows in the dark, NAEA were physically immobilized in EPN@EPX composite. CIE Lab and photoluminescence spectrum studies demonstrated that EPN@EPX bars turned greenish upon exposure to ultraviolet (UV) rays and greenish‐yellow in a darkened box. The luminous EPN@EPX morphologies and chemical compositions were analyzed using various analytical methods. The resistance to scratching of EPN@EPX bars was monitored to considerably increase with increasing NAEA concentration. The photoluminescence spectrum demonstrated two emission peaks at 437 and 518 nm. Photoluminescent EPN@EPX hybrids with low NAEA content have shown rapid photochromism reversibility. On the contrary, NAEA‐rich EPN@EPX bars displayed slow reversibility, glowing in the dark. Superhydrophobicity and UV blockage were found to be significantly improved in the luminescent colorless EPN@EPX hybrids.

Two viologen-based complexes as persistent luminescent materials and their applications in inkless print and anticounterfeiting

Viologen-based complexes have garnered significant attention due to their multifunctional stimuli-responsive properties and tunable persistent luminescence. However, achieving ultralong afterglow emission and color change in these complexes remains a challenge, limiting their application in the field of persistent luminescence. Herein, two novel viologen-based complexes were successfully designed and synthesized using N,N′-bis(2-carboxyethyl)-4,4′-bipyridinium dichloride (H2bybpy) ligands and trimesic acid (H3BTC) with the transition metals Zn(II)/Cd(II). Complexes 1 and 2 display reversible photochromic and electrochromic properties. Interestingly, complexes 1 and 2 in their crystal state exhibit dual fluorescence and persistent luminescence, emitting a green and cyan afterglow when the UV lamp is turned off at 77 K. Incorporating phosphorescent molecules and changing the metal significantly extended the duration of persistent luminescence and altered the hue. The complexes were also demonstrated to have potential applications in inkless printing, color-changing films, data encryption, and anti-counterfeiting. This work enhances the application of viologen-based complexes in light-controlled persistent fluorescence and provides ideas for achieving ultra-long afterglow emission.

Host-Guest Doping Modulated Afterglow Emission of Fluoroquinolones for Their Separation-Free Detection and Discrimination.

Detection and discrimination of fluoroquinolones (FQs) are crucial for food safety but remain a formidable challenge due to their minor differences in molecular structures and the serious interferences from food matrices. Herein, we propose an afterglow assay for the detection and discrimination of FQs through modulating their room-temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF) properties by a host-guest doping strategy. FQs were doped into the boric acid host, forming boronic anhydride structures and hydrogen bonds, which prompted the RTP and TADF performance of FQs by stabilizing their excited states, preventing triplet exciton quenching, and reducing the energy gap between singlet and triplet states. The FQs can be quantitatively detected through monitoring the afterglow intensity of host-guest systems, as low as 0.25 μg/mL. The differences in the afterglow intensity and emission lifetime allowed accurate discrimination of 11 types of FQs through pattern recognition methods. Aided by the delayed signal detection model of afterglow emission, the background signal and the interferences from food matrices were effectively eliminated, which endow the detection and discrimination of mixed FQs in commercial meat samples, without multiple-step separation processes.

Confinement reaction synthesis of CsPbBr3 quantum dots within long afterglow mesoporous materials as lighting equipment

Long afterglow materials are fluorescent materials with unique optical properties and excellent light-converting materials. However, long afterglow materials have the problem of emitting relatively single colors that are difficult to change, thus limiting their further application. Here, we propose a composite method of fully inorganic cesium lead perovskite quantum dots (QDs) with long afterglow materials, which uses the confinement reaction of CsPbBr3 in the pores of mesoporous CaAl2O4:Eu2+, Nd3+ (M-CAO) during high-temperature melting to form M-CAO-CsPbBr3. M-CAO-CsPbBr3 has better thermal and photostability than the common composite materials. Meanwhile, CsPbBr3 QDs can generate green afterglow emissions by absorbing the afterglow energy of M-CAO. In addition, the polydimethylsiloxane (PDMS) film formed by mixing the composite material phosphor M-CAO-CsPbBr3 with PDMS by heating and curing showed bright green fluorescence under 365 nm UV illumination, and it could still exhibit a weak green afterglow under dark conditions after stopping the irradiation. This article is an essential reference for long afterglow materials and anti-counterfeit labels.

Afterglow of Dual‐Confined Carbon Dots Ranging from Blue to Near‐Infrared

AbstractComprehensive research into afterglow emission in the near‐infrared (NIR) region of carbon dots (CDs) is currently lacking. In this study, highly efficient multicolor CDs are synthesized with fluorescence from blue to NIR using Rhodamine 6G. Boron oxide (B2O3) is employed as a matrix for encapsulating and confining the CDs, inhibiting triplet exciton quenching. Furthermore, structural rigidity is enhanced due to the formation of carbon‐boron (C─B) covalent bonds between CDs and B2O3, achieving tunable afterglow emission ranging from 463 to 722 nm with lifetimes up to 801 ms. The green–yellow afterglow composite exhibits an impressive quantum yield up to 37.67% while demonstrating thermally activated delayed fluorescence (TADF). Thus, this composite is coated onto a blue alternating‐current light‐emitting diode (BAC‐LED) to fabricate a white AC‐LED, which is successfully prepared with Commission Internationale de L'Eclairage (CIE) at coordinates of (0.32, 0.34), accompanied by the color rendering index (CRI) reaching 81.1. The bright afterglow compensates for zero‐point flickering in the BAC‐LED, resulting in stable and gentle emission. The potential applications of these luminescent materials in optoelectronic devices are undoubtedly widened by this remarkable advancement.

Room temperature, long afterglow, water-soluble materials with multicolor tunability

Developing solution-processable room-temperature long afterglow (RTLA) materials with multi-color tunable emissions based on an inorganic matrix is of considerable practical importance in diverse applications but rarely reported. Herein, a series of water-soluble multicolor afterglow materials (t@LP@Rh123, t@LP@Rh6G, t@LP@RhB, respectively) with afterglow emission colors of green, orange-yellow and red were achieved through triplet-to-singlet Förster-resonance energy transfer (T1-S1 FRET), where the cyan afterglow material t@LP obtained by solventless mechanical grinding method of 4-[2,2':6′,2″-Terpyridin]-4′-ylbenzoic acid and Laponite (LP) was used as an energy donor, and fluorescent dyes Rhodamine 123, Rhodamine 6G and Rhodamine B were used as energy acceptors. Notably, the obtained series of multicolor afterglow materials still exhibit obvious afterglow emission in aqueous solution, which make them potentially useful in the fields of anti-counterfeiting and multilevel information encryption.

Mechanism analysis on manipulation of long afterglow luminescence properties of Y3Al5-xGaxO12:Ce3+, Cr3+ phosphors

Blue-light activated long afterglow luminescence phosphors have attracted much attention because of their potential application in many fields. Herein, the influence of trap depth and the quantity of electrons captured by the traps on the long afterglow luminescence properties were systematically revealed through a comparative analysis of the long afterglow luminescence performance of the series of Y3Al5-xGaxO12(YAGG):Ce3+, Cr3+ (x = 0, 1, 2, 3, 4, 5) phosphors. To achieve long afterglow luminescence, it requires that the traps can effectively capture electrons, and possess an appropriate trap depth. Additionally, it is discovered that the quantity of electrons captured by the traps is the main factor affecting the duration of long afterglow luminescence. The more electrons are captured, the longer the afterglow lasts. The quantity of trapped electrons is inversely proportional to the energy differences between CBM-Ce5d and trap depth. The sample exhibits the high quantity of trapped electrons attributable to its small energy differences which allows electrons to be directly captured by traps through the tunneling effect. On this basis, the effects of crystal field splitting (εcfs), centroid shift (εc), and the degree of dodecahedral distortion (D (YO)) on trap depth (ET) were discussed to manipulate the trap depth, demonstrating there is a significant positive correlation between εc-εcfs(2(1-10D(YO))) and ET values for the garnet structure A3B2C3O12, when the ion doped at the A-position remains constant and the ions at the B and C positions vary. Notably, A larger D (YO) value corresponds to a deeper trap depth. This study provides a new perspective toward the development and design of long afterglow materials with superior afterglow emission.

The contemporaneous phase of GRB afterglows – application to GRB 221009A

ABSTRACT The TeV observations of GRB 221009A provided us with a unique opportunity to analyse the contemporaneous phase in which both prompt and afterglow emissions are seen simultaneously. To describe this initial phase of gamma-ray burst afterglows, we suggest a model for a blast wave with an intermittent energy supply. We treat the blast wave as a two-element structure. The central engine supplies energy to the inner part (shocked ejecta material) via the reverse shock. As the shocked ejecta material expands, its internal energy is transferred to the shocked external matter. We take into account the inertia of the shocked external material so that the pressure difference across this region determines the derivative of the blast wave’s Lorentz factor. Applied to GRB 221009A, the model yields a very good fit to the observations of the entire TeV light curve except for three regions where there are excesses in the data with respect to the model. Those are well correlated with the three largest episodes of the prompt activity and thus, we interpret them as the reverse shock emission. Our best-fitting solution for GRB 221009A is an extremely narrow jet with an opening angle θj ≈ 0.07° (500/Γ0) propagating into a wind-like external medium. This extremely narrow angle is consistent with the huge isotropic equivalent energy of this burst, and its inverse jet break explains the very rapid rise of the afterglow. Such inverse jet break occurs in an accelerating blast wave when the relativistic beaming becomes narrower than the jet’s opening angle. Interestingly, photon–photon annihilation does not play a decisive role in the best-fitting model.

Direct Population of Triplet States for Efficient Organic Afterglow through the Intra/Intermolecular Heavy-Atom Effect.

Organic afterglow is a fascinating phenomenon with exceptional applications. However, it encounters challenges such as low intensity and efficiency, and typically requires UV-light excitation and facile intersystem crossing (ISC) due to its spin-forbidden nature. Here, we develop a novel strategy that bypasses the conventional ISC pathway by promoting singlet-triplet transition through the synergistic effects of the intra/intermolecular heavy-atom effect in aromatic crystals, enabling the direct population of triplet excited states from the ground state. The resulting materials exhibit a bright organic afterglow with a remarkably enhanced quantum efficiency of up to 5.81%, and a significantly increased organic afterglow lifetime of up to 157 microseconds under visible light. Moreover, given the high-efficiency visible-light excitable organic afterglow emission, the potential application is demonstrated in lifetime-resolved, color-encoded, and excitation wavelength-dependent pattern encryption. This work demonstrates the importance of the direct population method in enhancing the organic afterglow performance and red-shifting the excitation wavelength, and provides crucial insights for advancing organic optoelectronic technologies that involve triplet states.

Self-confining isolated chiral chromophore for circularly polarized organic afterglow from amorphous polymer systems

Circularly polarized organic afterglow (CPOA) materials showing ultralong lifetime and chiral emission features have received widespread attention. However, generating CPOA emission remains a formidable challenge primarily due to the synergetic suppression non-radiative decay and chirality incorporation of triplet excitons. Herein, we propose a strategy to enable CPOA by covalently self-confining isolated chiral chromophores into the polymer matrix with rigidity and strong intermolecular interactions to effectively inhibit the non-radiative decay of chiral triplet excitons. The CPOA polymers exhibiting dual fluorescence and afterglow emission with a maximum luminescence dissymmetry factor of 1.06 × 10-2 and ultralong lifetime of up to 1.08 s have been achieved by crosslinking binaphthol derivatives into rigid self-host of polyacrylamide. Leveraging the superiority of afterglow and chiral attributes of CPOA polymers, advanced display and encryption demonstrations have been fabricated. This work underscores the significance of confining isolated chiral chromophores for the development of circularly polarized luminescent materials.

Photocured room temperature phosphorescent materials from lignosulfonate.

Photocured room temperature phosphorescent (RTP) materials hold great potential for practical applications but are scarcely reported. Here, we develop photocured RTP materials (P-Lig) using a combination of lignosulfonate, acrylamide, and ionic liquid (1-ethyl-3-methylimidazolium bromide). With this design, lignosulfonate simultaneously serves as RTP chromophore and photoinitiator. Specifically, lignosulfonate in the ionic liquid generates radicals to polymerize the acrylamide upon UV irradiation. The resulting lignosulfonate is automatically confined in an as-formed crosslinked matrix to provide RTP. As such RTP with an emission lifetime of ~110 ms is observed from the confined lignosulfonate in P-Lig. Additionally, energy transfer occur between P-Lig and Rhodamine B (RhB), triggering red afterglow emission when P-Lig is in situ loaded with RhB (P-Lig/RhB). As a demonstration of potential applications, the P-Lig and P-Lig/RhB are used as photocured RTP coatings and RTP inks for fabricating 3D materials and for information encryption.

Organic‐Inorganic Hybrid Ferroelectric and Antiferroelectric with Afterglow Emission

AbstractLuminescent ferroelectrics are holding exciting prospect for integrated photoelectronic devices due to potential light‐polarization interactions at electron scale. Integrating ferroelectricity and long‐lived afterglow emission in a single material would offer new possibilities for fundamental research and applications, however, related reports have been a blank to date. For the first time, we here achieved the combination of notable ferroelectricity and afterglow emission in an organic‐inorganic hybrid material. Remarkably, the presented (4‐methylpiperidium)CdCl3 also shows noticeable antiferroelectric behavior. The implementation of cationic customization and halogen engineering not only enables a dramatic enhancement of Curie temperature of 114.4 K but also brings a record longest emission lifetime up to 117.11 ms under ambient conditions, realizing a leapfrog improvement of at least two orders of magnitude compared to reported hybrid ferroelectrics so far. This finding would herald the emergence of novel application potential, such as multi‐level density data storage or multifunctional sensors, towards the future integrated optoelectronic devices with multitasking capabilities.

Organic-Inorganic Hybrid Ferroelectric and Antiferroelectric with Afterglow Emission.

Luminescent ferroelectrics are holding exciting prospect for integrated photoelectronic devices due to potential light-polarization interactions at electron scale. Integrating ferroelectricity and long-lived afterglow emission in a single material would offer new possibilities for fundamental research and applications, however, related reports have been a blank to date. For the first time, we here achieved the combination of notable ferroelectricity and afterglow emission in an organic-inorganic hybrid material. Remarkably, the presented (4-methylpiperidium)CdCl3 also shows noticeable antiferroelectric behavior. The implementation of cationic customization and halogen engineering not only enables a dramatic enhancement of Curie temperature of 114.4 K but also brings a record longest emission lifetime up to 117.11 ms under ambient conditions, realizing a leapfrog improvement of at least two orders of magnitude compared to reported hybrid ferroelectrics so far. This finding would herald the emergence of novel application potential, such as multi-level density data storage or multifunctional sensors, towards the future integrated optoelectronic devices with multitasking capabilities.