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To address the problem of cyan-green light deficiency in fluorescent converters for laser diode (LD) illumination applications, Ca 3-x Sc 2 Si 3 O 12 :xCe3+ (CSS:xCe3+) cyan-green fluorescent ceramics and CSS:Ce3+ phosphor in glass (CSS:Ce3+-PiG) fluorescent converter were successfully prepared. Among them, the CSS:0.08Ce3+ cyan-green fluorescent ceramic and 20 wt% CSS:Ce3+-PiG fluorescent converter had the highest luminescence intensity. At 450 nm excitation, the emission spectra of both materials showed an asymmetric broadband band between 470 nm and 690 nm. And the two fluorescent converters are not appear of luminescence temperature quenching until more than 538 K. The performance of the white LDs synthesized with ceramic and PiG converters was investigated. Under different power excitation, the green emission intensity of both wLD is enhanced with increased incident laser power. The wLDs based on CSS:Ce3+ fluorescent ceramics have a luminous flux of 880 l m and the maximum luminescence efficiency of 176 l m/W at an incident power of 5 W. And the wLDs of PiG fluorescent converters have a maximum luminous flux of 584 l m and luminescence efficiencies of up to 117 l m/W. CSS:Ce3+ ceramics and CSS:Ce3+-PiG are green fluorescent converter with good luminescence performance and thermal stability. It will play an important role in the compensation of the cyan light in LD illumination. [ABSTRACT FROM AUTHOR]

Lanthanide luminescence is dominated by quenching by high-energy oscillators in the chemical environment. The rate of non-radiative energy transfer to a single H2O molecule coordinated to a Eu3+ ion exceeds the usual rates of emission by an order of magnitude. We know these rates, but the details of these energy transfer processes are yet to be established. In this work, we study the quenching rates of [Eu(D2O)9]3+ and [Eu(DOTA)(D2O)]− in H2O/D2O mixtures by sequentially exchanging the deuterons with protons. Flash freezing the solutions allows us to identify species with various D/H contents in solution and thus to quantify the energy transfer processes to individual OH-oscillators. This is not possible in solution due to fast exchange in the ensembles present at room temperature. We conclude that the energy transfer processes are accurately described, predicted, and simulated using a step-wise addition of the rates of quenching by each O–H oscillator. This documents the sequential increase in the rate of the energy transfer processes in the quenching of lanthanide luminescence, and further provides a methodology to identify isotopic impurities in deuterated lanthanide systems in solution. [ABSTRACT FROM AUTHOR]

Aluminum garnets display exceptional adaptability in incorporating mismatching elements, thereby facilitating the synthesis of novel materials with tailored properties. This study explored Ce3+-doped Tb3Al5−xScxO12 crystals (where x ranges from 0.5 to 3.0), revealing a novel approach to control luminescence and photoconversion through atomic size mismatch engineering. Raman spectroscopy confirmed the coexistence of garnet and perovskite phases, with Sc substitution significantly influencing the garnet lattice and induced A1g mode softening up to Sc concentration x = 2.0. The Sc atoms controlled sub-eutectic inclusion formation, creating efficient light scattering centers and unveiling a compositional threshold for octahedral site saturation. This modulation enabled the control of energy transfer dynamics between Ce3+ and Tb3+ ions, enhancing luminescence and mitigating quenching. The Sc admixing process regulated luminous efficacy (LE), color rendering index (CRI), and correlated color temperature (CCT), with adjustments in CRI from 68 to 84 and CCT from 3545 K to 12,958 K. The Ce3+-doped Tb3Al5−xScxO12 crystal (where x = 2.0) achieved the highest LE of 114.6 lm/W and emitted light at a CCT of 4942 K, similar to daylight white. This approach enables the design and development of functional materials with tailored optical properties applicable to lighting technology, persistent phosphors, scintillators, and storage phosphors. [ABSTRACT FROM AUTHOR]

A new crystalline dinuclear Cu(I)/(II) complex (E.F: C32H28Cu2N6O14) (1) of terephthalic acid (TERE) and 1, 10‐Phenathroline (PHEN) was synthesized under one‐pot approach. Structure identification of the complex was carried out using the single crystal XRD technique, which revealed the penta coordination nature of Cu(I)/(II) in a square pyramidal environment. Further, the structural data was supported by employing other spectroscopic studies (UV, ESR, FT‐IR). In addition, the thermal stability and morphology of the complex were elucidated using TGA and SEM‐EDAX analysis. Photoluminescence experiments revealed the capability of 1 to act as a "turn‐off" sensor towards Zn2+ sensing. This luminescence quenching of 1 exhibited a threefold quenching in intensity by achieving a static quenching process corresponding to a limit of detection (LOD) of 3.7 μM. Further, considering the electroactive nature of Cu(I)/(II) complex, the cyclic voltammetric experiments were performed to study its competence to act as a modifier of GCE for the detection of glucose and its excellent potency to act as an effective electroactive material in the detection of glucose solutions. Also, molecular docking of 1 with human bovine serum (HSA) and bovine serum albumin (BSA) was investigated to prove their ability to act as pharmacological agents. [ABSTRACT FROM AUTHOR]

The misuse of ornidazole (ODZ) has caused serious harm to human-beings and environment. Hence, it is very important to develop efficient materials for sensing ODZ. In this article, a unique luminescent metal-organic framework (LMOF) [Cd(HATNA)1/2(2,6-NDC)1/2NO3·2H2O]n (1) was synthesized by cadmium nitrate, 2,6-naphthalenedicarboxylic acid (2,6-H2NDC) and 5,6,11,12,17,18-hexaazatrinaphthylene (HATNA) with a large π-conjugation skeleton. 1 displays a three-dimensional (3-D) framework, fabricated by 4-connected [Cd2(COO)2(NO3)2] cluster, single-bridged 2,6-NDC2− and double-chelated HATNA. It possesses excellent thermal and pH stabilities as well as luminescent properties. Significantly, 1 can efficiently detect ODZ in aqueous medium by luminescence quench effect. Notably, the quenching constant and detection limit of 1 towards ODZ reach 1.52×105 M−1 and 7.70 × 10−5 mM, respectively, which are the best values among those of LMOF-based ODZ sensors. Furthermore, the sensing mechanism of 1 towards ODZ has been investigated. [ABSTRACT FROM AUTHOR]

A new ternary coordination polymer (CP), {[Cd(L)(nip)(H2O)]·H2O}n (1) (L = 1,6-bis(benzimidazol-2-yl)hexane, H2nip = 5-nitroisophthalic acid), was hydrothermally synthesized and characterized. 1 is a two-dimensional sheet and extends into three-dimensional supramolecular networks through O-H···O hydrogen bonding interactions, which displays high thermal and pH stabilities. 1 demonstrated notable selectivity, sensitivity, and reusability for the luminescent sensing of chlortetracycline (CTC) and Fe3+ ions. Density functional theory calculations and UV−Vis absorption spectroscopy were employed to investigate the possible sensing mechanisms. A new Cd(II) metal coordination polymer, namely {[Cd(L)(nip)(H2O)]·H2O}n can act as a sensitive luminescent probe for chlortetracycline (CTC) and Fe3+ ions in water with excellent selectivity and recyclability. [ABSTRACT FROM AUTHOR]

In this work, NH2‐containing organic ligand 5‐Aminoisophthalic acid (AIPA), and trans‐1,2‐bis(4‐pyridyl)ethene (bpe) were selected as organic ligands to construct a new two‐dimensional luminescent Zn(II) metal‐organic framework [Zn(AIPA)(bpe)1/2]⋅named MOF‐1. It is worth noting that MOF‐1 exhibited excellent thermal stability and chemical stability in common solvents and different pH aqueous solution. As we expected, the luminescence sensing investigations demonstrated that MOF‐1 could be deemed as a multifunctional fluorescence sensor toward Cr2O72− and Fe3+ via a "turn‐off" effect. Notably, MOF‐1 had high selectivity and sensitivity for Fe3+ and Cr2O72− with low detection limits of 9.72×10−5 M and 1.95×10−5 M, respectively. Furthermore, the possible quenching mechanisms were also explored in detail. [ABSTRACT FROM AUTHOR]

In recent times, there has been significant interest in Mn4+-activated red phosphors in double perovskite oxide materials. However, the practical use of these materials is hindered by concerns related to their thermal and humidity stability. In this research, we have synthesized deep red-emitting phosphors with the composition La 2 LiNb (1- x) O 6 : x Mn4+ using a conventional high-temperature solid-phase method. The microstructures and luminescence properties of these phosphors have been thoroughly investigated. All the samples consist of irregular microcrystals with an average size ranging from 3 to 7 μm, and they exhibit excellent phase purity and crystallinity. Under excitation by 335 nm ultraviolet light, the La 2 LiNb (1- x) O 6 : x Mn4+ phosphors emit a narrow and sharp red band (centered at ∼710 nm), and the emission intensity initially increases and then decreases with increasing Mn4+-doping concentration, peaking at x = 0.5%. The La 2 LiNb 0.995 O 6 : 0.5%Mn4+ phosphor exhibits exceptional thermal stability, with a normalized emission intensity of 66.24% maintained at 150 °C. More importantly, the La 2 LiNb 0.995 O 6 :0.5%Mn4+ phosphor exhibits excellent humidity stability and can maintain more than 90% of its initial emission intensity after immersion in deionized water for 24 h. The La 2 LiNb 0.995 O 6 : 0.5%Mn4+ phosphor demonstrates an impressive resistance to humidity-induced luminescence quenching. It maintains a significantly higher far-red emission intensity at relative humidities exceeding 65%. These newly developed La 2 LiNb (1- x) O 6 : x Mn4+ phosphors hold great potential as red phosphors for high-power plant growth LEDs in extended outdoor, high-humidity conditions. [ABSTRACT FROM AUTHOR]

Film‐based fluorescence sensors are attractive for rapid and on‐site detection of illicit drugs, due to their potential for portability, high sensitivity and reusability. Three new bay‐substituted perylene diimide derivatives are synthesized , P1‐CH3 (1‐methyl), P1‐CF3 (1‐trifluoromethyl), and P1‐(CF3)2 (1,7‐di‐trifluoromethyl) that can be solution processed into thin films capable of detecting methamphetamine hydrochloride (MA•HCl) and cocaine•HCl via a luminescence quenching mechanism. The ionization potentials of the materials are sufficiently high to enable photoinduced hole transfer to occur, which led to the luminescence quenching. The trifluoromethyl‐substituted PDIs exhibit superior sensitivity and reversibility of the luminescence quenching process. In particular, P1‐(CF3)2 shows a limit of detection to MA•HCl of ≈100 ng after a 15‐second exposure, and its luminescence can be fully recovered either through mild heating or being placed in an air flow. Furthermore, by using the luminescence quenching and recovery responses of four PDI sensing materials it is possible to differentiate MA•HCl, cocaine•HCl, from aspirin, caffeine, sugar, and (sebum) skin oil in around a minute. [ABSTRACT FROM AUTHOR]

X-ray luminescent nanoparticles have gained significant attention as promising tools for implementing multimodal imaging and radiation-based treatments in theragnostics. The intricate comprehension of their properties and the underlying mechanisms driving the conversion of X-rays into light is critical for their success in various applications. LaPO 4 nanoparticles doped with various individual luminescence centers, gadolinium (Gd3+), europium (Eu3+), dysprosium (Dy3+), and terbium (Tb3+), were produced via co-precipitation and investigated for their behavior upon X-ray excitation using energies of up to 225 kV. These materials evidenced a radioluminescent response dependent on the dopant concentrations, with emission lines from 300 to 700 nm, providing insights into the luminescence quenching effect in these structures. The luminescent characteristics of the nanoparticles were studied under continuous irradiation, evidencing the materials' ability to withstand high absorbed doses and preserve their properties. Furthermore, the influence of dopant concentrations on crystallite size and the dependence of luminescence on thermal treatments was investigated. The assessment of nanoparticle stability in aqueous suspension was evaluated over a broad pH range, revealing a tendency of the LaPO 4 surface to selectively interact with electropositive species. This insight enhances our comprehension of the colloidal stability of the material, positioning it for extended applications and in vitro evaluations, along with further surface functionalization. [ABSTRACT FROM AUTHOR]

Different concentrations of B2O3 in zinc–aluminum–sodium–phosphate (ZANP) glasses were synthesized by the conventional melt-quenching method and analyzed using X-ray diffraction (XRD), optical absorption, excitation, visible luminescence, decay lifetime, and chromaticity methods. The amorphous nature of the glasses was confirmed by the absence of sharp diffraction peaks in the XRD profile. In the visible emission spectra blue, yellow, and red bands were observed and the intensity of the yellow band was superior. Furthermore, the samples show a luminescence quenching beyond 20 mol.% of B2O3 concentration. The decay lifetime of 4F9/2 of Dy3+ ions was found to be maximal in ZANP Dy0.5:20B2O3 glass. [ABSTRACT FROM AUTHOR]

Phosphor-converted white light emitting diodes (pc-WLEDs) as a new green lighting source have attracted considerable attention around the world. Single-component white light emitters are particularly attractive for fabricating economical solid-state devices for display and lighting. However, the emission loss of phosphors caused by thermal quenching is one of the important factors limiting its application. Herein, a series of single-phase Li 3 Ba 2 Y 3 (WO 4) 8 :Dy3+,Tm3+ phosphors were synthesized by solid state reaction. The crystal structure, electronic structure, morphology, temperature dependent photoluminescence and decay lifetimes were systematically studied by experimental and theoretical calculations. Under the UV excitation, the phosphor could easily emit yellow, blue and white light by simply tuning the ratio of Dy3+ to Tm3+ ions. Notably, the obtained phosphors showed an anti-thermal quenching at 422 K, and the luminous intensity remained 93.09 % of that at room temperature even up to 472 K. Moreover, the CIE chromaticity coordinates hardly changed with the increase of temperature. Ultimately, by combining the phosphor with a 365 nm NUV chip, a high-performance pc-WLED device with a correlation color temperature of 4333 K and CIE coordinates of (0.328,0.396) was successfully realized. This work indicates that the designed single-phase Li 3 Ba 2 Y 3 (WO 4) 8 :Dy3+,Tm3+ may be potential candidates for efficient single-phased white emission in pc-WLED lighting applications. [Display omitted] [ABSTRACT FROM AUTHOR]

The various structural and conductive attributes of barium cerate, BaCeO3 position it as a highly promising matrix for energy storage purposes. The current study illustrates that barium cerate can be effectively tailored by introducing trivalent praseodymium ions, thereby enhancing its optical properties as well. In this work, single-phased orthorhombic crystalline powders of barium cerate incorporated with Pr3+ (BaCeO3: Pr3+) were synthesized using the gel combustion procedure, followed by calcination. We conducted a comprehensive investigation into their crystal structure, vibrational characteristics, optical properties, and potential applications in wLEDs. The structure refinement indicates that Pr3+ occupies Ce4+ site, which results in the expansion of the cell and facilitates the generation of defects such as Pr Ce ′ and oxygen vacancies V O ⋅ ⋅ . By correlating information gathered from diffuse reflectance spectra with that obtained from photoluminescence spectra, we gained a deeper understanding of the electronic level structure and the mechanism of energy transfer. We successfully achieved a finely tuned cool white light emission with very low color purity (CP), a high color rendering index (CRI), and a high correlated color temperature (CCT) with a quantum efficiency of 36.3 % by exciting the material with a 321 nm wavelength. Because of the transfer of energy within activators through dipole–dipole interaction, luminescence quenching occurs when Pr3+ concentration reaches 1 wt%. To the best of our knowledge, this is the initial investigation of luminescence properties of Pr-incorporated barium cerate perovskites. [ABSTRACT FROM AUTHOR]

The surface ligands in colloidal metal halide perovskites influence not only their intrinsic optoelectronic properties but also their interaction with other materials and molecules. Donor–acceptor interactions of CsPbBr3 perovskite nanocrystals with TiO2 nanoparticles and nanotubes are explored by replacing long‐chain oleylamine ligands with short‐chain butylamines. Through postsynthesis ligand exchange, the nanocrystals are functionalized with butylamine ligands while their intrinsic properties are maintained. In solution, butylamine‐capped nanocrystals exhibit reduced photoluminescence intensity with increasing TiO2 concentration but without any change in photoluminescence lifetime. Intriguingly, the Stern–Volmer plot depicts different slopes at low and high TiO2 concentrations, suggesting donor‐acceptor interaction through mixed static photoluminescence quenching and quenching sphere of action mechanism. Oleylamine‐capped nanocrystals in solution, on the other hand, show no interaction with TiO2, as indicated by consistent photoluminescence intensities and lifetimes before and after TiO2 addition. In films, both types exhibit decreased photoluminescence lifetime with TiO2, indicating enhanced donor–acceptor interaction, which is discussed in terms of electron transfer. TiO2 nanotubes enhance nonradiative recombination more in butylamine‐capped CsPbBr3 perovskite nanocrystals, emphasizing the role of ligand chain length. [ABSTRACT FROM AUTHOR]

Currently, the unique 5D 4 energy level of terbium (Tb3+) can contribute to narrow-band green light emission, which has high application prospects. However, due to its poor thermal stability at high temperatures, how to enhance the antithermal-quenching properties of Tb-doped phosphors has become a research difficulty in the field of solid-state lighting and temperature sensing. In this contribution, the antithermal-quenching green-emitting of terbium was achieved by Nb/Ta substitution to form GdNb 1-x Ta x O 4 :Tb3+ phosphors with various components. Photoluminescence analyses reveal an increasing trend in both the optical band gap and the intervalence charge transfer (IVCT) energy level positions with substitution. Variable-temperature spectrums observed that the phosphors under different compositions presented a large discrepancy in thermal quenching performance. It is elucidated that the elevated position of the IVCT energy level (IVCT-EL) predominantly influences thermal quenching, bolstering its role as a compensatory luminescence channel of 5D 3 →5D 4 far more than functioning as a quenching luminescence channel for Tb3+5D 3 /5D 4. Delving into the perspective of IVCT-EL positioning unveils the intrinsic mechanism through which IVCT-EL positions modulate the thermal quenching properties of phosphors with varying compositions due to the substitution of Ta for Nb. This insight facilitates the realization of enhanced thermal quenching resistance in phosphors. Furthermore, the antithermal-quenching property of Tb3+ in single-phase phosphors can be effectively modulated by excitation at different wavelengths. This tuning scheme not only advances the exploration of terbium-doped antithermal-quenching phosphors but also provides a novel strategy and reference for designing green-emitting phosphors in the fields of lighting and sensing. [Display omitted] [ABSTRACT FROM AUTHOR]

Cytisine (CTS) is a useful medicine for treating nervous disorders and smoking addiction, and exploring a convenient method to detect CTS is of great significance for long‐term/home medication to avoid the risk of poisoning, but it is full of challenges. Here, a modified metal–organic framework sensor Tb@Zn‐TDA‐80 with dual emission centers was prepared using a post‐modified luminescence center strategy. The obtained Tb@Zn‐TDA‐80 can serve as a CTS sensor with high sensitivity and selectivity. To achieve portable detection, Tb@Zn‐TDA‐80 was further fabricated as a membrane sensor, M−Tb@Zn‐TDA‐80, which displayed an obvious CTS‐responsive color change by simply dropping a CTS solution onto its surface. Benefiting from this unique functionality, M−Tb@Zn‐TDA‐80 successfully realized the visual detection and quantitative monitoring of CTS in the range of 5.26–52.6 mM by simply scanning the color with a smartphone. The results of nuclear magnetic resonance spectroscopy and theoretical computation illustrated that the high sensing efficiency of Tb@Zn‐TDA‐80 for CTS was attributed to the N−H⋅⋅⋅π and π⋅⋅⋅π interactions between the ligand and CTS. And luminescence quenching may result from the intramolecular charge transfer. This study provides a convenient method for ensuring long‐term medication safety at home. [ABSTRACT FROM AUTHOR]

Cytisine (CTS) is a useful medicine for treating nervous disorders and smoking addiction, and exploring a convenient method to detect CTS is of great significance for long‐term/home medication to avoid the risk of poisoning, but it is full of challenges. Here, a modified metal–organic framework sensor Tb@Zn‐TDA‐80 with dual emission centers was prepared using a post‐modified luminescence center strategy. The obtained Tb@Zn‐TDA‐80 can serve as a CTS sensor with high sensitivity and selectivity. To achieve portable detection, Tb@Zn‐TDA‐80 was further fabricated as a membrane sensor, M−Tb@Zn‐TDA‐80, which displayed an obvious CTS‐responsive color change by simply dropping a CTS solution onto its surface. Benefiting from this unique functionality, M−Tb@Zn‐TDA‐80 successfully realized the visual detection and quantitative monitoring of CTS in the range of 5.26–52.6 mM by simply scanning the color with a smartphone. The results of nuclear magnetic resonance spectroscopy and theoretical computation illustrated that the high sensing efficiency of Tb@Zn‐TDA‐80 for CTS was attributed to the N−H⋅⋅⋅π and π⋅⋅⋅π interactions between the ligand and CTS. And luminescence quenching may result from the intramolecular charge transfer. This study provides a convenient method for ensuring long‐term medication safety at home. [ABSTRACT FROM AUTHOR]

The thermally reversible luminescent materials with information encryption are important and widely used in the information age. However, it is challenging to obtain such materials. In this work, a 0D In‐based hybrid compound [(CH3)3NCH2CHCH2]2InCl5 ((TAMAC)2InCl5) is synthesized and undergoes a high‐temperature ferroelastic phase transition with an Aizu notation of m3¯$\bar{3}$mF2/m at 333 K. In the room temperature phase (RTP), it shows a weak blue glow with a photoluminescent quantum yield (PLQY) of 0.32% under the UV lamp at 365 nm. By using a metal ion doping strategy to improve the photophysical properties, a series of compounds is obtained: (TAMAC)2In1‐xCl5:xSb3+ (x = 0.1%,0.5%,1%, and 1.5%, x represents the actual amount) with the same ferroelastic phase transition as that found in (TAMAC)2InCl5. When x = 0.5%, the PLQY reaches 50.66% with the luminous color change from blue to orange. Interestingly, it is found that the orange luminescence of the doped materials can rapidly and reversibly quench and recover between heating and cooling cycles, where the thermally induced phase transition results in this thermally reversible luminescence phenomenon. This discovery reveals the mechanism of luminescence quenching and phase transition, and provides a new pathway for the construction of new thermal‐sensitive luminescent materials with information encryption. [ABSTRACT FROM AUTHOR]

Doping has been proven to be a good way to regulate the optical and electrical properties of the active elements including both inorganic and organic materials. In this paper, the study demonstrates a bipolar doping strategy for an intrinsic charge‐transfer binary‐complex through the use of p‐ and n‐type dopants, which incorporate toward highly‐ordered ternary complexes. Benefitting from the good lattice matching and energy level tuning, the supramolecular system with a large doping concentration range (0 ≤ x ≤ 50% or 40%) assembles into the original crystal lattice and exhibits tunable luminescence or quenching phenomena even at very low ratio. The 7h‐benzo[c]carbazole (BCZ) dopped cocrystals show yellow–green to red emission due to the Förster resonance energy transfer (FRET); while only 5% 7,7,8,8‐tetracyanoquinodimethane (TCNQ) dopant can bring superior photothermal (PT) behavior with a high PT conversion efficiency up to 75.3%, owing to the efficient non‐radiative decay way contribution. It is believed that the strong π–π interactions and free rotation of −C(C≡N)2 promote this decay way transition. This work on the charge‐transfer complex doping system suggests the great potential in optical, photothermal imaging, and therapy applications as well as information memory and photo sensing. [ABSTRACT FROM AUTHOR]

Methylation reactions are chemically simple but challenging to perform under mild and non-toxic conditions. A photochemical energy transfer strategy was merged with copper catalysis to enable fast reaction times of minutes and broad applicability to N-heterocycles, (hetero)aromatic carboxylic acids, and druglike molecules in high yields and good functional group tolerance. Detailed mechanistic investigations, using kinetic analysis, aprotic MS, UV/Vis, and luminescence quenching experiments revealed a triplet-triplet energy transfer mechanism between hypervalent iodine(III) reagents and readily available photosensitizers. [ABSTRACT FROM AUTHOR]

A series of Tb3+-doped Sr2YTaO6 double perovskite phosphors (SYT:Tb3+) were synthesized using a conventional solid-state reaction method. A strong green emission was observed in the SYT:Tb3+ phosphors, and the optimal doping concentration of Tb3+ was confirmed to be 5 mol%. The electric dipole-dipole interaction was ascribed to be the main mechanism for the luminescence concentration quenching. Analysis of the concentration-dependent fluorescence decay confirmed that the self-generated quenching model holds for the dynamic process of Tb3+ decays in SYT. Furthermore, the internal quantum efficiencies, non-radiative transition rates, and energy transfer rates of the 5D4 level for the SYT:Tb3+ samples were estimated, respectively. The luminescence thermal stability of the sample was also evaluated based on the Arrhenius model. The chromaticity shift of the SYT:5 mol% Tb3+ phosphor was examined to be 0.013 when the sample temperature was increased from 303 to 483 K, thus indicating excellent chromaticity shifting resistance under high temperature conditions. Moreover, the Judd-Ofelt parameters were calculated from the emission spectra of SYT:Tb3+ to be Ω2 = 0.29 × 10-20, Ω4 = 0.45 × 10-20, and &@937;6 = 0.72 × 10-20 cm², respectively. The fluorescence branching ratios and radiative transition rates for the 5D4 level were calculated based on the obtained Judd-Ofelt parameters. Finally, a white light-emitting diode (LED) prototype was assembled using a 310 nm LED chip combined with a prepared green SYT:Tb3+ phosphor and two other commercial blue and red phosphors. The obtained warm white light exhibits good chromaticity coordinates (0.32, 0.32) and a high color rendering index of 96.1. Based on the above results, it can be known that the prepared SYT:Tb3+ phosphors have a potential application as green emitting phosphors in white LEDs. [ABSTRACT FROM AUTHOR]

Reversible upconversion luminescence (RUCL) through defect engineering holds great promise for various applications, including photoswitches, information recording, and storage devices. However, the reversible photoluminescence in inorganic crystals is rarely reported. Crucially, the underlying mechanism of reversible luminescence remains unclear, which challenges the design of high‐performance reversible luminescence inorganic materials. Herein, an anomalous RUCL in a class of β‐Ba2ScAlO5:Yb3+/RE3+ (RE = Er, Ho, Tm, Tb, Sm, or Eu) phosphors is reported. By alternating annealing environments (air or hydrogen), a robust and repeatable cycle of luminescence and quenching is observed. The first‐principles calculations reveal that porous β‐Ba2ScAlO5:Yb3+/RE3+ can host oxygen interstitials (during annealing in air) with a low formation energy. The interstitial oxygen state, close to the Yb 4f state, leads to luminescence quenching. Removal of oxygen interstitials (during annealing in hydrogen) can restore the luminescence by initiating radiative energy transfer. Experimentally, the existence of interstitial oxygen is confirmed with neutron diffraction technology. It is worth noting that the strong chemical bonds in crystals make adding and removing anion vacancies challenging, unlike the more "free" interstitials. The findings offer new insights into manipulating upconversion luminescence in inorganic crystals by defect engineering and provide motivation for future research in this field. [ABSTRACT FROM AUTHOR]

The accurate and rapid detection of antibiotics and heavy-metal-based toxic oxo-anions in water media employing coordination polymers (CPs) as luminescent probes has attracted a lot of attention. Three new Cd(II)-based ternary CPs derived from first-presented L ligands, including [Cd(DCTP)(L)(OH)]n (1), [Cd(TBTA)(L)(OH)]n (2), and [Cd(NPHT)(L)(H2O)]n (3) (L = 2-((1H-imidazol-1-yl)methyl)-5,6-dimethyl-1H-benzo[d]imidazole, H2DCTP = 2,5-dichloroterephthalic acid, H2TBTA = tetrabromoterephthalic acid and H2NPHT = 3-nitrophthalic acid), were successfully assembled and characterized. 1 and 2 show 2D hcb layers, which can be further extended into a 3D supramolecular framework via classic hydrogen bonding interactions. 3 features a 1D double chain that ultimately spreads into a 2D network through weak hydrogen bonding interactions. With the advantages of high stability and excellent luminescent properties, the three CPs display high sensitivity, selectivity, and good anti-interference for the sensing of pefloxacin (PEF) and Cr2O72− ions (LOD values toward PEF: 3.82 × 10−7 mol L−1 for 1, 4.06 × 10−7 mol L−1 for 2, and 1.36 × 10−8 mol L−1 for 3, and toward Cr2O72− ions: 5.97 × 10−7 mol L−1 for 1, 5.87 × 10−7 mol L−1 for 2, and 8.21 × 10−8 mol L−1 for 3). These CPs are the first examples of bifunctional luminescent sensors to detect PEF and Cr2O72− in aqueous solutions. The luminescence quenching mechanisms are explored in detail. [ABSTRACT FROM AUTHOR]

Fluoroborates have garnered significant research interest due to their intricate structure and unique nonlinear optical properties. In this work, pure and Eu-activated Ba 5 B 4 O 10 F 2 were prepared via the high-temperature solid-state ceramic method. Ba 5 B 4 O 10 F 2 is a wide band semiconductor (E g = 4.51 eV) with an indirect transition characteristic. The optical absorption, photoluminescence, and dynamic spectra of Eu2+/3+ activators were investigated. Luminescence intensities of Eu2+ and Eu3+ had distinctly different responses to doping content. The residual Eu3+ centers in Ba 5-5 x Eu 5 x B 4 O 10 F 2 (x > 0.03) cannot be avoided even it was sintered in a reducing atmosphere. Time-resolved spectra and decay curves also confirm the presence of Eu3+ with Eu2+. Under near-UV light excitation, a strong emission band from the 5d→4f transition of Eu2+ was detected overlapping with sharp peaks from (5D 0 →7F 0,1,2,3,4) of Eu3+ in Ba 5-5 x Eu 5 x B 4 O 10 F 2 (x > 0.03). As the Eu-doping level increases, the intensity ratio of Eu2+ and Eu3+ changes regularly, and the luminescent intensity of Eu3+ obviously and systematically becomes stronger. As the temperature changes from 25 °C to 150 °C, the luminescent intensity of Eu3+ increases, while that of Eu2+ gradually decreases. The results confirm the energy transfer (ET) from Eu2+ to Eu3+ in Ba 5 B 4 O 10 F 2. Eu3+ can act as killers, leading to the luminescence quenching of Eu2+ activators. The heterovalent substitution of Eu and NaF in Ba 5 B 4 O 10 F 2 not only reduces the content of Eu3+ but also significantly enhances the efficiency of Eu2+. The experiments demonstrate that to improve the luminescence efficiency of Eu2+, it is important to focus on reducing the residual Eu3+ in the lattice through enhancing the reduction from Eu3+ to Eu2+. [ABSTRACT FROM AUTHOR]

Combination of affordable organic dyes of high quantum yield with silicon can be an interesting way for development of highly efficient thin film photovoltaic cells utilizing silicon sensitisation. This work is focused on investigating the energy transfer processes including photon tunnelling from photosensitive molecules of BASF R305 high quantum yield dye to silicon substrate. Energy transfer from dye molecules to silicon substrate is evaluated by measuring the quenching of molecular photoluminescence lifetime using time-correlated single photon counting (TCSPC) technique. Energy transfer is further studied in dependence on dye layer thickness. The results can be useful for further studies leading to design of ultrathin silicon solar cells. [ABSTRACT FROM AUTHOR]

The article describes the synthesis and spectroscopic properties of Sr3WO6:Nd3+ NIR emitting phosphor. The X-ray diffraction analysis confirms the formation of the compound. The Rietveld refinement analysis indicates that the crystal structure is a distorted triclinic system with space group P–1 (C1). The band bap of Sr3WO6:Nd3+ is reported as ≈3 eV from the Kubelka–Munk equation. The phosphor is excited at the wavelength of 824 nm of NIR spectrum. The excitation spectrum is spread over from the visible to the NIR region. The PL emission is obtained in the NIR region with a prominent characteristic emission line at 1083 nm. The obtained PL emission is due to the occupancy of Nd3+ ions in Sr22+–O and Sr62+–O lattice sites. The quenching of luminescence intensity is due to the exchange interaction mechanism between the host Sr2+ site and dopant Nd3+ ion. As per spectroscopic analysis, Sr3WO6:Nd3+ phosphor may be considered as a promising candidate towards solid–state laser applications. [ABSTRACT FROM AUTHOR]

Thermal quenching is the core challenge that hinders the application of luminescent materials. Herein, a synergistic mechanism involving energy transfer and energy gap modulation is proposed based on the local crystal field regulation around sensitizers. The substitution of coordination cation V5+/P5+ weakens the crystal field strength of the sensitizer Bi3+, and the weakening of crystal field splitting causes an increase in the 3P1 energy level, thus increasing its energy gap. Compared with the YVO4:Bi3+,Eu3+ phosphor, the thermal stability of the YV0.25P0.75O4:Bi3+,Eu3+ phosphor is significantly improved, and the relative emission intensity of Eu3+ continuously increases with heating and reaches 1.24 times the original intensity at 523 K and does not show a decreasing trend in the studied temperature range. The anti-thermal quenching performance is mainly attributed to the increasing thermal quenching activation energy (ΔE) of the sensitizer by energy gap modulation, which enhances the energy transfer to compensate thermal quenching. Based on the thermal quenching characteristics of the materials, an optical thermometer is designed. The maximum relative sensitivity (Sr) and absolute sensitivity (Sa) are as high as 1.74% K−1 and 0.59 K−1, respectively, and the minimum temperature resolution reaches 0.288 K. The synergistic effect between energy gap modulation of the sensitizer and energy transfer enables the regulation of thermal quenching. Thus, this study provides a new strategy for exploiting high-performance luminescent materials. [ABSTRACT FROM AUTHOR]

Herein, a series of Y2W3O12:10%Yb3+/x%RE3+ (RE = Er/Ho/Tm) phosphors is prepared via a solid-state reaction. The upconversion and downshift luminescence properties of the phosphors were investigated under an excitation of 980 nm. The bright blue light emission from Tm3+ ion and the green and red light emissions from Ho3+(Er3+) ions were observed. The near-infrared light intensity of NIR-I (Tm3+, ∼850 nm), NIR-II (Er3+: ∼1550 nm; Tm3+: ∼1783 nm) and NIR-III (Ho3+: ∼2050 nm) were analyzed. In particular, the dramatic thermal enhancement phenomenon in visible and NIR regions was exhibited by the Y2W3O12:10%Yb3+/x%RE3+ (RE = Er/Ho/Tm) phosphors. Among them, the green light intensity of Er3+ ions increased 26.77 times, from 303 to 573 K. The NIR-II emission band (∼1783 nm) intensity of Tm3+ ions at 533 K increased 168.7 times compared to that at 313 K. The possible thermal enhancement mechanism is illustrated by the negative thermal expansion (NTE) and Frenkel defect of the Y2W3O12 host. Finally, the optical temperature sensing performances of Y2W3O12:10%Yb3+/x%RE3+ (RE = Er/Ho/Tm) samples are investigated according to the luminescence intensity dependence relationship on temperature. The maximum value of SR reached 4.24% K−1 at 353 K for Y2W3O12:10%Yb3+/0.6%Ho3+ phosphor. The results indicate that the Y2W3O12:10%Yb3+/x%RE3+ (RE = Er/Ho/Tm) phosphors possess anti-thermal quenching properties and are suitable for developing optical temperature sensors. [ABSTRACT FROM AUTHOR]

A series of compounds of the form [HAr]2[UO2X4] is reported here, wherein Ar is systematically varied between pyridine (1‐X), quinoline (2‐X), acridine (3‐X), 2,5‐dimethylpyrazine (4‐X), quinoxaline (5‐X), and phenazine (6‐X), and X=Cl or Br. With greater conjugation in the organic cation, a larger quenching in uranyl luminescence is observed in the solid state. Supporting our luminescence experiments with computation, we map out the potential energy diagrams for the singlet and triplet states of both the [HAr]+ cations and [UO2Cl4]2− anion in the crystalline state, and of the assembly. The distinct energy transfer pathways in each compound are discussed. [ABSTRACT FROM AUTHOR]

A series of compounds of the form [HAr]2[UO2X4] is reported here, wherein Ar is systematically varied between pyridine (1‐X), quinoline (2‐X), acridine (3‐X), 2,5‐dimethylpyrazine (4‐X), quinoxaline (5‐X), and phenazine (6‐X), and X=Cl or Br. With greater conjugation in the organic cation, a larger quenching in uranyl luminescence is observed in the solid state. Supporting our luminescence experiments with computation, we map out the potential energy diagrams for the singlet and triplet states of both the [HAr]+ cations and [UO2Cl4]2− anion in the crystalline state, and of the assembly. The distinct energy transfer pathways in each compound are discussed. [ABSTRACT FROM AUTHOR]

The novel red-emitting phosphors Ba 3 Lu 1– x Eu x B 9 O 18 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.85) belonging to the Ba 3 REE B 9 O 18 (REE – Y, Pr–Lu) family were successfully obtained by a multistep solid-phase synthesis. X-ray diffraction experiments revealed no phase transitions caused by the Eu3+ → Lu3+ isomorphic substitution in this series of solid solutions. An increase in the Eu3+ content leads to an expectable increase of hexagonal unit cell parameters and volume. Optical properties of the Ba 3 Lu 1– x Eu x B 9 O 18 (x = 0–0.85) phosphors were investigated. The highest emission intensity was demonstrated by Ba 3 Lu 0.6 Eu 0.4 B 9 O 18. The concentration quenching of luminescence was revealed for the x (Eu3+) > 0.4 samples. Concentration quenching, quantum yield and structural data were compared between three red-emitting Ba–Lu borates-phosphors (BLBO:Eu3+) containing independent crystallographic sites for the REE ions (n = 1–3) in crystal structure. It was revealed that the higher the number of nonequivalent cationic REE sites suitable for the Eu3+ → Lu3+ substitution, the higher the quantum yield taking into account practically equal amount of an optimal concentration of the activator-ion. Such an observation could be useful for a crystal chemical design of novel phosphors. [Display omitted] • Novel red-emitting phosphors Ba 3 LuB 9 O 18 :Eu3+ are synthesized. • Optical properties of the phosphors are studied. • Luminescence and structural data of three Ba–Lu borates-phosphors are compared. • Dependence of quantum yield on number of nonequivalent REE cationic sites is discussed. [ABSTRACT FROM AUTHOR]

Upconversion luminescence (UCL) is a fluorescence process where two or more lower-energy photons convert into a higher-energy photon. Lanthanide (Ln3+)-doped UCL materials often suffer from weak luminescence, especially when directly synthesized by a hydrothermal (HT) process due to the existing hydroxyl group and undesirable arrangement of dopants within host lattices which quench luminescence and limit energy transfer. Therefore, additional heat treatment processes are required to enhance their UCL emission, even though direct hydrothermal synthesis without further heat treatment has the advantages of low energy consumption, fast synthesis, and wide applicability to generate UCL materials. In this study, via a HT process without annealing, we have produced Yb3+ and Er3+ co-doped SrMoO4 submicron spindles with a strong green UCL emission which can be seen with the naked eye, which HT produced oxide-based UCL materials often fail to demonstrate. We have investigated different HT synthesis conditions, such as temperature, time, pH and dopant composition, which control the nucleation, growth, lattice structure arrangement, and ultimately their UCL properties through XRD, SEM, EDS and UCL measurements. The bright green UCL from the SrMoO4:Yb,Er submicron spindles is further enhanced by post-synthesis annealing within a molten NaNO3/KNO3 system to prevent particle size growth. The green UCL intensity from the annealed SrMoO4:Yb,Er submicron spindles surpasses samples produced by the solid-state method and is comparable to that from the commercial NaYF4:Yb,Er sample. We have further studied the temperature-dependent luminescence of both the HT-prepared and molten-salt annealed SrMoO4:Yb,Er submicron spindle samples. The strong UCL from our SrMoO4:Yb,Er submicron spindles could warrant their candidacy for bioimaging and anticounterfeiting applications. [ABSTRACT FROM AUTHOR]

Noninvasive sonodynamic therapy (SDT) shows promise for brain glioma treatment due to deep tissue‐penetrating capabilities (>10 cm) of ultrasound and high spatial resolutions. Yet, this technique is hindered by inefficient production of reactive oxygen species (ROS), resulting from the hypoxic tumor microenvironment (TME), high level of ROS scavenger glutathione (GSH), and the inability to visualize glioma in vivo for precise treatment management and monitoring in current sonosentizers. To address these challenges, we fabricated a core‐shell heterostructure sonosensitizer (labeled as DFM), in which meso‐tetra (4‐carboxyphenyl) porphine (TCPP) porphyrin metal‐organic frameworks (MOF, PCN‐224(Fe)) serve as a porous shell to contain approved chemotherapeutics sorafenib (SRF) to effectively inhibit GSH synthesis, while NaErF4:Yb@NaLuF4 nanoparticles as the core provide TME‐responsive NIR IIb (≈1500–1800 nm) luminescence at 1525 for precise optical imaging. Coordination of Fe3+ into the macrocycle of TCPP at the MOFs shell is found to, besides triggering ferroptosis, reduce TCPP phosphorescence (23% decrease) and increase the triplet state (T1) oxygen quenching, substantially promoting the singlet oxygen generation (2.6‐fold increase). Furthermore, GSH in TME facilitates the reduction of Fe3+ to Fe2+, thereby eliminating the luminescence quenching of Fe3+ and augmenting the NIR IIb luminescence of Er3+ (5‐fold increase) for nanoagents accumulation imaging in intracranial glioma, realizing dynamical monitoring of SDT processes. Compared to control groups, in vitro and in vivo experiments confirm the effective ROS generation and results in a 6‐fold volume reduction of brain gliomas, reaching a survival rate of 80% at 30 days posttreatment. [ABSTRACT FROM AUTHOR]

It is challenging to explore novel-structure lanthanide coordination polymers (Ln-CPs) for sensing environmental pollutants. Herein, we designed and synthesized an organic bridging linker 3-(carboxymethoxy)-1-(carboxymethyl) pyrazole-4-carboxylic acid (H3ccpc), and then successfully prepared and characterized a novel Ln-CP, namely [Tb2(ccpc)2(H2O)6]·1.5H2O (ccpcTb). Structural analysis indicates that ccpcTb exhibits a two-dimensional structure, in which Tb ions are in an eight-coordinated environment. The photoluminescence performance of ccpcTb was discussed in detail. The ccpcTb displays bright green luminescence and behaves as a multi-responsive luminescent sensor toward Fe3+ ions, Cr2O72− ions and 2,4,6-trinitrophenol with high selectivity and low detection limits. Furthermore, the possible luminescence sensing mechanisms have been addressed in detail. The luminescence quenching mechanism of sensing Fe3+ and Cr2O72− is attributed to the energy competitive absorption, while that of sensing TNP is due to the synergistic effect of energy competitive absorption and photo-induced electron transfer. [ABSTRACT FROM AUTHOR]

So far, overcoming thermal quenching remains a huge challenge in the application of phosphor materials. The intervalence charge transfer (IVCT) state has an inestimable role in the compensation of antithermal-quenching effects and is widely used in the research of applications in optical temperature sensing, yet little study has been reported on its modulation of thermal quenching properties. In this contribution, the thermal quenching properties of praseodymium-activated solid-solution substituted GdNb 1-x Ta x O 4 phosphors were investigated systematically for the inaugural time from the perspective of IVCT energy level positions. According to the empirical formula, the IVCT level positions in the phosphor increase sequentially from 32960.71 cm−1 to 33442.15 cm−1, the DFT calculates the extension of the substrate band gap from 3.6408 eV to 4.3066 eV, and the contributing energy level of the conduction band is determined. The variation in the position of the IVCT energy level explains the alteration of the luminescence intensity at room temperature for different composition phosphor 3P 0 and 1D 2 energy levels. More particularly, it was analyzed that in the variable temperature spectra, x = 0–0.75 exhibited different degrees of efficient antithermal-quenching properties at 303–523 K, while no antithermal-quenching was presented at x = 1. By analyzing the IVCT energy level position and other influencing factors such as band gap, the feasibility of the IVCT energy level position as a competing model for the compensation and quenching channels is established, and the internal mechanism of regulating thermal quenching property is revealed. Effective control of the phosphor resistance to thermal quenching performance was achieved, which directly determines whether enhanced or diminished thermal quenching can be obtained. This finding provides a new effective strategy for the tuning of thermal quenching luminescence of Pr3+-doped Nb/Ta system phosphors. [Display omitted] [ABSTRACT FROM AUTHOR]

So far, overcoming thermal quenching remains a huge challenge in the application of phosphor materials. The intervalence charge transfer (IVCT) state has an inestimable role in the compensation of antithermal-quenching effects and is widely used in the research of applications in optical temperature sensing, yet little study has been reported on its modulation of thermal quenching properties. In this contribution, the thermal quenching properties of praseodymium-activated solid-solution substituted GdNb 1-x Ta x O 4 phosphors were investigated systematically for the inaugural time from the perspective of IVCT energy level positions. According to the empirical formula, the IVCT level positions in the phosphor increase sequentially from 32960.71 cm−1 to 33442.15 cm−1, the DFT calculates the extension of the substrate band gap from 3.6408 eV to 4.3066 eV, and the contributing energy level of the conduction band is determined. The variation in the position of the IVCT energy level explains the alteration of the luminescence intensity at room temperature for different composition phosphor 3P 0 and 1D 2 energy levels. More particularly, it was analyzed that in the variable temperature spectra, x = 0–0.75 exhibited different degrees of efficient antithermal-quenching properties at 303–523 K, while no antithermal-quenching was presented at x = 1. By analyzing the IVCT energy level position and other influencing factors such as band gap, the feasibility of the IVCT energy level position as a competing model for the compensation and quenching channels is established, and the internal mechanism of regulating thermal quenching property is revealed. Effective control of the phosphor resistance to thermal quenching performance was achieved, which directly determines whether enhanced or diminished thermal quenching can be obtained. This finding provides a new effective strategy for the tuning of thermal quenching luminescence of Pr3+-doped Nb/Ta system phosphors. [Display omitted] [ABSTRACT FROM AUTHOR]

Luminescence thermal quenching (TQ) is one of the most critical problems to be solved for further improvement of phosphors' applications in lighting and many other fields. Herein, a novel strategy is demonstrated to achieve outstanding anti‐TQ performance with a substantial enhancement of Eu3+ red emission at 613 nm from Sc2MO3O12:Tb3+,Eu3+ phosphor. Its anti‐TQ performance is endowed by dual energy transfer (ET) pathways and intensified by the negative thermal expansion (NTE) property of the Sc2MO3O12 host. Remarkably, the photoluminescence (PL) emission intensity of Eu3+ from Sc2MO3O12:20%Eu3+,2%Tb3+ phosphor at 648 K reaches 507.3% of the initial intensity taken at 298 K. The lifetime of Eu3+ emission at 613 nm elongates with increasing measurement temperature. The experimental data and density functional theory (DFT) calculations reveal that the host structure shrinkage via NTE leads to the thermally boosted Eu3+ red emission by intensifying the consecutive ET and confinement of the absorption light. The potential of this phosphor as a dual‐mode high temperature thermometer based on both emission lifetime and intensity ratio read‐out modes is realized. This work provides inspiration to combine multiple strategies to achieve broad and dramatic anti‐TQ phosphors with enhanced performance for various optical applications. [ABSTRACT FROM AUTHOR]

Photochromic materials have been found to be promising for a broad range of applications. However, it remains a great challenge to develop new photochromic materials. In this work, a dihydroanthracene-based photochromic organic molecule 9,10-bis(di(pyridine-4-yl)methylene)-9,10-dihydroanthracene (L) was developed as a functional ligand to construct a LMOF-based sensor material [Cd2L(HBTC)2·2H2O·2i-PrOH]n (1) (LMOF = luminescent metal–organic framework; H3BTC = benzene-1,3,5-tricarboxylic acid; i-PrOH = isopropanol). 1 is constructed using a 6-connected [Cd2(COO)2]2+ cluster, a 4-connected L unit and a HBTC double-bridge and exhibits a two-dimensional (2-D) (4,6)-connected architecture. 1 has good water and thermal stability. Before and after photochromism, this LMOF exhibits different luminescence properties, which results in dual-response and highly selective sensing properties. 1 can detect TNP with high sensitivity and selectivity in aqueous media by luminescence quenching effects. More importantly, 1′ (1 after photochromism) shows ultrahigh sensing sensitivity and selectivity towards MnO4− (the second highest Ksv of 4.08 × 105 M−1). Furthermore, 1′ can identify MnO4− in the presence of a similar strong oxidizing anion Cr2O72−. In addition, quenching sensing mechanisms are discussed in detail. This work will contribute to the development of highly efficient dual-response sensors. [ABSTRACT FROM AUTHOR]

Novel and high-security anti-counterfeiting technology has always been the focus of attention and research. This work proposes a nanocomposite combination of upconversion nanoparticles (UCNPs) and perovskite quantum dots (PeQDs) to achieve color-adjustable dual-mode luminescence anti-counterfeiting. Firstly, a series of NaGdF4: Yb/Tm UCNPs with different sizes were synthesized, and their thermal-enhanced upconversion luminescence performances were investigated. The upconversion luminescence (UCL) intensity of the samples increases with rising temperature, and the UCL thermal enhancement factor rises as the particle size decreases. This intriguing thermal enhancement phenomenon can be attributed to the mitigation of surface luminescence quenching. Furthermore, CsPbBr3 PeQDs were well adhered to the surfaces and surroundings of the UCNPs. Leveraging energy transfer and the contrasting temperature responses of UCNPs and PeQDs, this nanocomposite was utilized as a dual-mode thermochromic anti-counterfeiting system. As the temperature increases, the color of the composite changes from green to pink under 980 nm excitation, while it displays green to non-luminescence under 365 nm excitation. This new anti-counterfeiting material, with its high security and convenience, has great potential in anti-counterfeiting applications. [ABSTRACT FROM AUTHOR]

In this paper, Fe 3 O 4 /α-Fe 2 O 3 /Y 2 O 3 :Eu3+ multifunctional nanocomposites were synthesized using a hydrothermal method. Fe 3 O 4 /α-Fe 2 O 3 /Y 2 O 3 :Eu3+ nanocomposites are core-shell nanostructures consisting of a superparamagnetic nanomagnetite core, which is converted to hematite during the synthesis. As a theranostic material, hematite could be used in drug-release processes, while nanomagnetite generates heat in a hyperthermia cancer treatment. An outer shell of Y 2 O 3 :Eu3+ nanophosphor is added to give nanocomposites photoluminescent properties and to render them visible in bioimaging. Structural, optical, and magnetic features of nanocompositesare studied using X-ray diffraction (XRD), fourier-transform infrared spectroscopy (FTIR), Raman, photoluminescence (PL), vibrating-sample magnetometer (VSM), and high-resolution transmission electron microscope (HRTEM) techniques. Photoluminescence properties of nanocomposites show a quenching effect related to the proportion of magnetite and Y 2 O 3 :Eu3+. A luminescence quenching mechanism is proposed based on the optical effects of a core-shell structure. Magnetic saturation grows proportionally with the amount of magnetite present, which indicates that Fe 3 O 4 magnetic structure is not altered, even by the hematite that forms around it. The synthesized nanocomposites possess a core-shell morphology modified by the different proportions of their components. The optical, structural, and magnetic nanocomposite properties found will be of interest in theranostic materials research in the biomedical field. [ABSTRACT FROM AUTHOR]

Luminescence quenching at high dopant concentration and temperature typically limits the brightness of luminescence materials, which remains a major obstacle in diverse technological applications, especially in the field of luminescence thermometry. In this work, a unique class of non‐concentration quenching double‐tungstate phosphors is reported that feature the near‐unity quantum yield of Tb3+ and Eu3+ emissions induced by the structural confinement effect. Mechanistic studies affirm that the activator ions can be isolated in NaYW2O8 crystal to confine the absorbed photon energy, leading to a relatively high quenching concentration of various lanthanide activators. By facilitating interionic cross‐relaxation at heavy dopant concentration, a remarkable thermal enhancement of Tb3+ emissions over 20‐fold upon the excitation of excited‐state absorption is recorded. In contrast, thermally quenched emissions are detected under the excitation of ground‐state absorption. This excitation wavelength‐dependent thermal behavior of Tb3+ emissions is harnessed for single‐band ratiometric thermometry, registering superior thermal sensitivity and resolution (Sr = 4.01% K−1, δT = 0.1 K). The advances in combating concentration and thermal quenching of luminescence materials provide exciting opportunities for flexible thermometry in real‐world sensing scenarios. [ABSTRACT FROM AUTHOR]

Photodynamic and photothermal therapy (PDT and PTT) have been widely used in tumor treatment researches owe to its advantages of spatiotemporal controlliability and non-invasiveness. Combining two phototherapy strategies together and/or with chemodynamic therapy (CDT) could achieve better therapeutic efficiency, but the resulting inconvenient dual-laser irradiation and the potential skin toxicity limit its development. Moreover, the lack of tumor-specificity causes side-effects to normal tissues. Therefore, shortening the irradiation time, or integrating two lasers, and increasing tumor specificity are necessary to reduce side effects. Herein, we developed a tumor microenvironment responsive one-laser-excited PDT/PTT/CDT synergistic therapeutic nanosystem ZPPSC (refers to ZGGC-PDA-PEI-Si-Pc-Cu) for precise tumor phototherapy. In this nanosystem, the simultaneous PTT and PDT activation using a single laser, enhancing phototherapy efficiency while reducing phototoxicity were achieved. Specifically, persistent luminescence nanoparticle ZnGa 1.6 Ge 0.2 O 4 :Cr (ZGGC) is coated with polydopamine (PDA) through self-polymerization of dopamine, modified with polyethyleneimine (PEI), Si-Pc, and adsorbed with Cu2+. Cu2+ quenches the persistent luminescence (PersL) in physiological environment, and could be reduced to Cu+ under the excess GSH in tumor cells, resulting in removing from nanosystem. Whereafter, PersL is restored, and Fenton-like reaction between Cu+ and overexpressed H 2 O 2 is triggered to generate ·OH for CDT therapy. Under single 808-nm irradiation, PDA will be irradiated to perform PTT, and the opening persistent luminescence could irradiate photosensitizers for PDT and continues to stimulate them even after the laser stops, reducing external excitation time. The in vivo results shown that ZPPSC exhibit ideal PDT performance, and increased local temperature close to 60 °C. Most importantly, the tumor inhibition rate by combined PTT, PDT, CDT with 5-min 808-nm laser irradiation is 99%, and even one mouse was completely cured with the bearing tumor completely disappeared. By using this nanosystem, PDT and PTT were achieved by only on laser with relatively short irradiation time. Moreover, the weak tissue penetration of the 660-nm PS excitation source was also addressed. Our design achieves tumor-specific one-laser three-mode phototherapy with shortened irradiation time, enhancing therapy effectiveness while minimizing side effects. These results exhibit great therapeutic outcomes of ZPPSC for precious tumor phototherapy. One-laser-excited three-model therapy nanosystem is prepared for tumor specific treatment. Cu2+ realizes tumor-responsive PDT process "turn on" and CDT, PDT and PTT are co-excited by one laser simultaneously. [Display omitted] [ABSTRACT FROM AUTHOR]

Thin films of two poly(dendrimer)s were studied for the detection of trace quantities of nitro-based taggants and explosives. The poly(dendrimer) structures consist of side chain-conjugated triphenylamine-based dendritic chromophores attached to a non-conjugated polymer backbone. The poly(dendrimer)s differ in terms of the conjugation length, steric bulk and surface groups of the chromophores and we investigated the effects of these differences on sensing performance. We found that the addition of first-generation biphenyl-based dendrons to the chromophores of one of the polymers, P2 , resulted in greater photoluminescence quenching, sensitivity and recovery to pulses of the vapours of the nitroaliphatic taggant 2,3-dimethyl-2,3-dinitrobutane (DMNB) and the nitroaromatic analyte 2,4-dinitrotoluene (2,4-DNT) compared with the other polymer, P1. We employed neutron reflectometry to characterise the vapour uptake of both poly(dendrimer)s and a structurally similar triphenylamine-based dendrimer D1 for comparison. The results show that the P2 has a mass density of 0.91 ± 0.01 v. 1.01 ± 0.01 g cm−3 for both P1 and D1 and can absorb at least twice the amount of 2,4-DNT. These results show how increasing the dendritic character of the poly(dendrimer) architecture provides a route for optimising vapour uptake and improving sensing performance in the solid state. Thin films of two poly(dendrimer)s differing in conjugation length, steric bulk and surface groups were studied for the detection of trace quantities of nitro-based taggant and explosive vapours. Addition of first-generation biphenyl-based dendrons led to a decrease in mass density, an increase in analyte sorption and improved detection. (Image credit: Paul L. Burn.) CH23131_TOC.jpg [ABSTRACT FROM AUTHOR]

Two Al-MOFs, i.e., MIL-53 (Al) and (NH2)-MIL-53 (Al) have been synthesized using aluminium nitrate as metal ligands and 1,4 benzene dicarboxylic acid, amino 1,4 benzene dicarboxylic acid as organic linkers in aqueous medium at room temperature, respectively. Both Al-MOFs have been confirmed through different microscopy and spectroscopy tools. Afterwards, the optical properties of Al-MOFs have been confirmed in polar and non-polar solvents using photoluminescence spectroscopy. Finally, both Al-MOFs have been explored for optical nitrobenzene (NB) sensing. Interestingly, we have found excellent optical ability of NH2-MIL-53 (Al) over MIL-53 (Al) due to structural π–π* transitions. The photo-induced electron transfer mechanism has been found during the MOF–analyte interaction. Importantly, we confirmed that NH2-MIL-53 (Al) is an excellent sensing material for NB with a 0.28 ppb limit of detection over MIL-53 (Al). [ABSTRACT FROM AUTHOR]

A Cd(II)-based metal–organic framework (MOF), [Cd(PDA)(L)2] (PDA = 1,4-phenylenediacetate and L = 2,4,5-tri-4-pyridyl-1H-imidazole), 1, was synthesized by a solvothermal method and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The single-crystal X-ray studies showed that the connectivity among Cd2+ ions, PDA and 2,4,5-tri-4-pyridyl-1H-imidazole ligands forms two-dimensional structures. The two-dimensional structures are arranged in an AAA....fashion to form a three-dimensional packing arrangement. Compound 1 showed selective and efficient sorption of the large anionic dye remazol brilliant blue R (RBBR) in aqueous medium, whereas it exhibited low sorption towards orange G (OG), methyl orange (MO), methylene blue (MB) and rhodamine B (RhB). Compound 1 also exhibited photoluminescence-based sensing behaviors towards Fe3+, Cr3+ and Al3+ ions in aqueous medium based on the luminescence quenching effect. However, photoluminescence studies in the presence of other common metal ions such as Cd2+, Cu2+, Mg2+, Ca2+, Co2+, K+, Mn2+, Pb2+, Zn2+, and Na+ in aqueous medium showed a negligible turn-on effect. The limits of detection for Fe3+, Cr3+, and Al3+ ions were 75, 257 and 107 ppb, respectively. Compound 1 also showed comparable gas sorption capacity towards CO2 (64.5 cm3 g−1), N2 (72.25 cm3 g−1) and H2 (45.30 cm3 g−1) at 1 bar. [ABSTRACT FROM AUTHOR]

The effect of modifying the composition of a glass matrix based on the Ga2S3-GeS2:Pr3+ system due to the addition of La2S3 on the structure and the optical and luminescent properties of these glasses has been studied. It has been shown that the addition of La2S3 leads to changes in the nearest structural environment of Ga, Ge, and S and increases the degree of ionicity of the bonds of the Pr3+ ion. Despite the existence of a large glass formation region in the Ga2S3-GeS2-La2S3 system and the structural and chemical similarity of La and Pr, La2S3 does not promote a more uniform distribution of Pr3+ ions in the glass matrix, and thus does not reduce the concentration quenching of the luminescence of Pr3+ ions. However, the addition of La2S3 increases the probability of emission of Pr3+ ions and decreases the radiative lifetime. Additionally, it was shown that, when studying the structure and luminescent properties of glasses with La, it is necessary to take into account a significant concentration of rare earth traces (Pr and Nd). [ABSTRACT FROM AUTHOR]

Structural and thermal stability are two essential conditions in phosphor research, which are related to the structure of the host and the position of 4T 2 energy lever in Mn4+-activated phosphors. Here, Mn4+-activated CaGdAlO 4 phosphor with superior structural stability was synthesized through systematically screening the aluminate family of ABAlO 4 (A = Mg, Ca, Sr, Ba; B Sc, Lu, Y, Gd, La). Sr2+ was subsequently introduced to modulate the 4T 2 state level of Mn4+ for achieving better thermal stability in CaGdAlO 4 :Sr2+,Mn4+ phosphor. The luminescence quenching temperature T 1/2 show a parabolic trend with the increasing of Sr2+ dopant in Ca 1-y GdAlO 4 :ySr2+, Mn4+ phosphors, and change from 403 K to 426 K and 387 K in CaGdAlO 4 :Mn4+, Ca 0.4 GdAlO 4 :0.6Sr2+,Mn4+ and SrGdAlO 4 :Mn4+ three samples, respectively. The corresponding crystal-field calculations confirm that a certain amount of Sr2+ doping can improve the 4T 2 state of Mn4+ and obtain better thermal stability in the phosphor. All the samples have deep-red emission located at 712 nm, which matches well with the absorption spectra of green vegetables. This deep-red light accelerate morphological formation and increase vegetable biomass. This work is expected to stimulate more exploration of Mn4+-doped oxide phosphors with better structural and thermal stability for emerging applications of agricultural lighting. [ABSTRACT FROM AUTHOR]

Y2Ti2O7:Cr3+/Yb3+/Nd3+ phosphors with broadband near-infrared emission were developed by a high-temperature solid-state method. Under the excitation of 405 nm light, it shows broadband near-infrared emission from 650 to 1050 nm. Y2Ti2O7:Cr3+/Yb3+/Nd3+ phosphors present excellent bright luminescence and thermal quenching resistance. The energy transfer mechanism between Cr3+/Nd3+/Yb3+ ions was elucidated. By using the energy transfer from Cr3+-Nd3+-Yb3+, the excitation efficiency of Yb3+ at 405 nm is greatly improved, and the strong NIR emission centered at approximately 975 nm is well coupled with the absorption band of silicon solar cells. The Y2Ti2O7:0.005Cr3+/0.1Yb3+/0.01Nd3+ phosphors were assembled with a commercial 365 nm InGaN chip to fabricate a near-infrared LED device that can work under operating electric currents of 100–900 mA. In short, Y2Ti2O7:Cr3+/Yb3+/Nd3+ phosphors are suitable for near-infrared LED applications. [ABSTRACT FROM AUTHOR]

The abuse of ornidazole (ODZ) has great threats to human being. Therefore, it is essential to develop efficient methods to detect ODZ. In this article, an unusual luminescent metal–organic framework (LMOF) [Cd3(HATNA)(TPA)3·5H2O]n (1) was synthesized by cadmium nitrate, 5,6,11,12,17,18-hexaazatrinaphthylene (HATNA) with large π-conjugation skeleton, and terephthalic acid (TPA). 1 exhibits a six-connected [Cd3(COO)6] cluster-based three-dimensional (3D) framework, supported by double-chelated HATNA bridges, and double and single TPA bridges. Noteworthily, this double-chelated HATNA firstly appears in MOFs. 1 has good thermal and pH stabilities, and exhibits luminescent property. More importantly, 1 can efficiently detect ODZ in H2O medium by luminescence quenching effect. Particularly, the ODZ detection limit of 1 is 2.26 × 10–4 mM, which is the lowest in LMOF-based ODZ sensors. Meanwhile, the detection mechanism of 1 towards ODZ has been discussed. [ABSTRACT FROM AUTHOR]

Large negative thermal quenching (NTQ) of the yellow luminescence (YL) for a temperature increase from 5 to 300 K is observed in non-polar InGaN/GaN quantum well (QW) samples due to the thermal migration of carriers from the InGaN QW layers to the GaN barrier layers for the first time. Such an unusual phenomenon happens only when the carriers are optically excited inside the QW layers, providing solid evidence for the occurrence of thermal transfer of photoexcited carriers from the QW layers to the GaN barrier layers. A simple model considering the thermal transfer of carriers is proposed to interpret the observed NTQ phenomenon. The thermal activation energy of the carriers is determined by fitting the reciprocal temperature dependence of the YL intensity in the Arrhenius plot with the model. [ABSTRACT FROM AUTHOR]