Luminescence Of Ions Research Articles

Web-based application software for Judd-Ofelt analysis of Eu3+ ion luminescence

This article reports on the development of a new Web-based application software for calculating Judd-Ofelt intensity parameters and derived quantities from the emission spectra of Eu3+ doped compounds. The application was entirely developed in JavaScript, and it is compatible with all major browsers. The web application can be accessed via the following link https://sciapps.sci-sim.com/judd_ofelt_analysis_Eu.html. Test samples of ZnO doped with different amounts of Eu3+ were synthesized using the combustion method, and their radiative properties and the chemical environment in the Eu surroundings were thoroughly investigated by Judd-Ofelt intensity and the derived parameters using the online application. In contrast to the tediousness and time-consuming process of these types of calculations, by using this online software, all intensity parameters and the derived quantities can be obtained within a short time.

Designing tunable emissions and mechanoluminescence in piezoelectric luminescent ions doped oxysulfide compounds by cations substitution for optical sensing

Piezoelectric mechanoluminescent materials capable of directly converting external mechanical stimulation into light are decisive for the development of optoelectronic sensing devices. However, emission spectral modulation is highly demanded for mechanoluminescent materials, which is important for applications. Here, we have doped luminescent ions into the piezoelectric semiconductor oxysulfide compounds (Sr,Ba)ZnOS using the salt-fusion method to form multi-mode emission materials. The prepared luminescent compounds can simultaneously generate photoluminescence and mechanoluminescence for temperature and stress sensing. The tunable photoluminescence can be obtained for multi-color emissions by controlling concentrations of luminescent ions Mn2+ and Er3+. Subsequently, the materials are combined with polydimethylsiloxane matrix to prepare smart mechanoluminescence films for optical sensing. The mechanoluminescence and tunable emissions from prepared film make this luminescent materials promising in the fields of dynamic imaging of force and anti-counterfeiting.

Luminescence of iron ions in crystals: Site occupancy, valence states, and excited-state properties

Luminescence of iron ions in crystals: Site occupancy, valence states, and excited-state properties

Luminescence properties of CdF2 single crystals co-doped with Er3+ and Y3+ ions.

The luminescence properties of erbium and yttrium co-doped cadmium difluoride with three different concentrations of yttrium were investigated. First, we synthesized single crystal samples with good optical quality using the Bridgman technique. From the optical absorption spectra, recorded at room temperature, both in the ultraviolet-visible and infrared spectral ranges, Judd-Ofelt analysis was performed based on yttrium concentrations to predict the radiative properties of Er3+ luminescent ions. For the 10% optimum concentration of yttrium, a detailed photoluminescence investigation was carried out. We mainly explored green, red, and near-infrared fluorescence under different excitation wavelengths and presented their highlight spectroscopic characteristics. The desired transitions had relatively high emission cross-sections both under visible and near-infrared excitation. Optical gain followed a similar trend. Furthermore, the dynamic fluorescence study showed a significant increase in the measured lifetime under an 800 nm infrared excitation. The upconversion process under an 800 nm excitation produced quantum efficiency greater than 100% due to the contribution of more than one energy transfer mechanism.

Preparation of chalcogenide perovskite SrHfS3 and luminescent SrHfS3:Eu2+ thin films

As an emerging family of perovskites with S or Se anions, chalcogenide perovskites possess excellent optoelectronic properties that are comparable with halide perovskites, e.g., efficient carrier transport abilities and defect tolerance. Moreover, they are thermodynamically stable and constituted by eco-friendly elements. Among them, chalcogenide perovskite SrHfS3 is found to be a promising light emitting material and is experimentally demonstrated to be a suitable host for the luminescent lanthanide ions like Eu2+. In order to be applied in practical light emitting devices, preparation of the thin film is a critical step. Unfortunately, there are few reports on the growth of SrHfS3 thin films, hindering the knowledge of their thin film properties and applications. In this work, SrHfS3 thin films are prepared by magnetron sputtering from a commercial SrHfO3 target and subsequent sulfurization. Then, Eu2+ doping in SrHfS3 thin films is achieved by co-sputtering from a home-made EuS target. The SrHfS3 thin films exhibit high-quality crystallinity, smooth morphology, and high p-type mobility. With efficient Eu2+ doping strategy, SrHfS3:Eu2+ thin films show intensive red light, which sets foundations for their further application in practical light emitting devices.

Europium Metal–Organic Framework Polymer Composites with Enhanced Luminescence and Selective Ferric Ion Sensing

Europium Metal–Organic Framework Polymer Composites with Enhanced Luminescence and Selective Ferric Ion Sensing

Fluorescent probe effect of super-sensitive transition Dy3+ ions in the negative thermal expansion materials Sc2W3O12

Negative thermal expansion (NTE) materials have attracted significant attention for their distinctive thermal expansion properties and potential applications in various fields such as micro-electronic packaging, aerospace engineering, optics, and sensors. Despite significant advancements, the field continues to face numerous challenges, including scarcities in material types, unclear mechanisms underlying thermal shrinkage, response temperature far from room temperature, as well as limited potential for industrialization. In our work, we report a type of Sc2W3O12:Dy3+ luminescent material whereby the doped super-sensitizing rare earth ion Dy3+ can form luminescent centers within a specific crystal field environment, thereby extending the optical properties of NTE materials. With the temperature increasing, the emission of WO42− undergoes a red shift, and the yellow-to-blue (Y/B) ratio resulting from Dy3+ transitions increase, effectively illustrate the W–O bond spacing decreases. The effect of lattice shrinkage with increasing temperature is proved by the optical performance of luminescent ions in the NTE materials, gives rare earth ions the role of fluorescent probes in the process of negative thermal expansion. This also provides a novel strategy for the dynamic monitoring of lattice environments that vary with temperature.

Customizing the luminescent properties of compositionally disordered ceramics (Gd, Y, Yb, Tb, Ce)3Al2Ga3O12: From an ultra-fast scintillator to bright, wide-spectrum phosphor

A series of (Gd, Y, Yb, Tb, Ce)3Al2Ga3O12 compositionally disordered compounds with a garnet structure were prepared in the form of ceramics by sintering in oxygen at 1650 °C for 2 h and studied for the luminescent properties and interaction of ions entering the matrix host. The luminescence features of Ce3+ ions were found to be strongly dependent on the Yb concentration. Photoluminescence and scintillation kinetics are characterized by subnanosecond kinetics when the Yb index in the compound exceeds X = 0.3. It opens an opportunity to create an extremely fast and dense scintillation material emitting in a visible range. A further decrease in the Yb index in the compound leads to an increase in the intensity of Yb3+ infrared (IR) emission, whereas Ce3+ and Tb3+ ions contribute to the luminosity of the material by overlapping intra- and intereconfiguration luminescence bands in the spectral range of 300–700 nm. This finding opens an opportunity to create converter materials tolerant to the corpuscular radiation of isotope sources, providing a high efficiency of electric current production when coupled with a silicon photovoltaic element. The compounds were engineered at the nanoscale level, providing control over electronic excitation transfer between luminescent ions.

Bandgap engineering—Influence of the evolution of (Zn/Mg)Al2O4:Cr3+ spinel phosphors on the photoluminescence properties

AbstractAs a luminescent center ion in materials for deep red and near‐infrared light, Cr3+ has been extensively studied in octahedral host materials. In this study, using zinc aluminate (ZnAl2O4) and magnesium aluminate (MgAl2O4) spinels with abundant octahedra as substrates, a series of Zn1−xMgxAl2O4:0.5%Cr3+ (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) fluorescent powders were first prepared via a high‐temperature solid‐state method. The influence of different Mg/Zn ratios on (Zn/Mg)Al2O4:0.5%Cr3+ optical properties was thoroughly explored. Experimental results show that an increase in the Mg/Zn ratio reduces the crystal field strength (Dq) and leads to distortion of the [AlO6] octahedra, resulting in broadening of the photoluminescence emission spectrum. Furthermore, the addition of Mg gradually reduces the formation of inverse spinel. An appropriate Mg/Zn ratio can improve luminescent intensity and quantum efficiency. In summary, this paper, through bandgap engineering by adjusting the Mg/Zn ratio, provides a detailed account of the changes in optical properties and the underlying mechanisms during the transition from ZnAl2O4:0.5%Cr3+ to MgAl2O4:0.5%Cr3+ spinels. It offers valuable insights for further research on the practical applications of Cr3+ in areas such as lighting displays and bioimaging.

Contrasting impact of coordination polyhedra and site symmetry on the electronic energy levels in nine-coordinated Eu(III) and Sm(III) crystals structures determined from single crystal luminescence spectra.

Lanthanide luminescence is characterised by "forbidden" 4f-4f transitions and a complicated electronic structure. Our understanding of trivalent lanthanide(III) ion luminescence is centered on Eu3+ because absorbing and emitting transitions in Eu3+ occur from a single electronic energy level. In Sm3+ both absorbing and emitting multiplets have a larger multiplicity. A band arising in transitions from the first emitting state multiplet to the ground state multiplet will have nine lines for a Sm3+ complex. In this study, high-resolution emission and excitation spectra were used to determine the electronic energy levels for the lowest multiplet and first emitting multiplet in four Sm3+ compounds with either tricapped trigonal prismatic TTP or capped square antiprismatic cSAP coordination polyhedra but different site symmetry. This was achieved by the use of Boltzmann distribution population analysis and experimentally determined transition probabilities from emission and excitation spectra. Using this analysis it was possible to show the effect of changing three oxygen atoms with three nitrogen atoms in the donor set for two compounds with the same coordination polyhedra and site symmetry. This work celebrates the 40th anniversary of Kirby and Richardson's first report of [Eu(ODA)3]3- luminescence.

Constructing micro/nano-photonics barcodes based on micro-region upconversion emission spectrum of single core-shell microcrystal

The construction of core-shell structures with different structural properties based on the epitaxial growth technique has become an effective technique for regulating the luminescence properties of micro/nanocrystals. In order to obtain richer spectral information, NaYF<sub>4</sub>:50%Yb<sup>3+</sup>/2%Tm<sup>3+</sup>@NaYF<sub>4</sub>@NaYF<sub>4</sub>:20%Yb<sup>3+</sup>/2%Er<sup>3+</sup>@NaYF<sub>4</sub>@NaYbF<sub>4</sub>:2%Er<sup>3+</sup> multilayered core-shell microcrystals are prepared by using multiple epitaxial growth through introducing surface modifiers and controlling their reaction conditions. The XRD and SEM results clearly show that the core-shell microcrystals possess a pure hexagonal crystal structure in the form of a disk. The microdesk has a thickness of about 2.32 μm and a diameter of about 28.31 μm. The upconversion luminescence characteristics of different single microcrystal structures are investigated by a confocal microspectroscopy system. In order to realize the selective excitation and emission of a single microcrystal, the spatial distribution of luminescent ions can be controlled through introducing an intermediate isolation layer. Under 980 nm laser excitation, different excitation sites of the single microdisk exhibit different upconversion emission characteristics. The significant blue (450 and 475 nm), red (648 nm) and green (524 and 540 nm) emissions are observed, which mainly originat from Tm<sup>3+</sup> and Er<sup>3+</sup> radiative transitions. Meanwhile, the red and blue upconversion emission intensities of the microcrystals are improved by using various shell layers. In addition, the luminescence and energy-transfer features of single microcrystals are explored by changing the excitation position. The experimental results demonstrate that the incorporation of NaYF<sub>4</sub> inert shells between luminescent layers can regulate luminescence and prevent ions from interacting. By utilizing the spectral fingerprint data of dopant ions in various shell layers, we create customizable micro-nano photonic barcodes and employ them for optical anti-counterfeiting detection. This study explores the use of constructed core-shell structures with luminescent tunable micron core-shell structures to acquire diverse spectral information and maintain stability through their structural properties. Thus, this core-shell structure provides a novel method for using upconversion luminescent microcrystals into micro- and nanophotonics to achieve anti-counterfeiting and display purposes.

Frontiers of Deep-Red Emission of Mn4+ Ions with Ruddlesden-Popper Perovskites.

It is well-known that the chemical composition of the host material significantly affects the spectroscopic performance of transition metal ions. However, it is worth noting that also the structure and symmetry of crystallographic sites play significant roles in transition metal ion luminescence. In this study, we demonstrate three perovskite structures of strontium titanate forming so-called Ruddlesden-Popper phases doped with Mn4+ ions. The observed reduction in the average Ti4+-O2- distance in the series SrTiO3-Sr2TiO4-Sr3Ti2O7 allowed for a record-breaking shift in the spectral position of Mn4+ emission band with a maximum of around 734 nm and led to an improvement of the already impressive thermometric performance of SrTiO3:Mn4+ in ratiometric and lifetime-based approaches. This research encourages a further search for structures that, with the help of the developed correlations between structural and optical properties, could lead to the discovery of phosphors beyond the limits established so far.

Optical and scintillation properties of modified LSO crystals with different ions doping grown by a rapid CZ system

LSO:Ce is a well-known scintillation crystal that is widely used in nuclear medicine, security checks, and high-energy physics. The scintillation properties of LSO can be modified by doping to meet the ever-growing requirements of radiation detection. However, exploring new doping techniques for LSO crystals with self-designed scintillation features remains time-consuming, especially by the Czochralski (CZ) method. In this paper, we established a high-efficiency crystal growth system based on the CZ method for the rapid growth of LSO crystals. The system is regulated by a high-accuracy auto-diameter controller to grow small boules of ϕ 20 mm × 100 mm. By incorporating an arc bottom crucible and optimizing the temperature field, the crystallization fraction of the as-grown crystal can be increased to 95% with the growth period compressed to 48 h. With the aid of the growth system, LSO crystals with Lu3+ partially substituted by optical inertia RE ions (Sc3+, Y3+, La3+, Gd3+), metal cations co-doping (Ca2＋, Li1+, Yb3+), and different luminescent ions doping (Pr3+, Nd3+, Eu3+, Tb3+, Dy3+, Yb3+) are grown. Comparative analysis shows that the Ca co-doped LSO:Ce exhibits the best scintillation performance, taking into account both light output and decay time, among our samples. Moreover, Tb-doped LSO features relatively good scintillation efficiency with various wavelengths of visible light emission.

Controlled formation of gold nanoparticles with tunable plasmonic properties in tellurite glass

Silicate glasses with metallic nanoparticles (NPs) have been of intense interest in art, science and technology as the plasmonic properties of these NPs equip glass with light modulation capability. The so-called striking technique has enabled precise control of the in situ formation of metallic NPs in silicate glasses for applications from coloured glasses to photonic devices. Since tellurite glasses exhibit the unique combination of comparably easy fabrication, low phonon energy, wide transmission window and high solubility of luminescent rare earth ions, there has been a significant amount of work over the past two decades to adapt the striking technique to form gold or silver NPs in tellurite glasses. Despite this effort, the striking technique has remained insufficient for tellurite glasses to form metal NPs suitable for photonic applications. Here, we first uncover the challenges of the traditional striking technique to create gold NPs in tellurite glass. Then, we demonstrate precise control of the size and concentration of gold NPs in tellurite glass by developing new approaches to both steps of the striking technique: a controlled gold crucible corrosion technique to incorporate gold ions in tellurite glass and a glass powder reheating technique to subsequently transform the gold ions to gold NPs. Using the Mie theory, the size, size distribution and concentration of the gold NPs formed in tellurite glass are determined from the plasmonic properties of the NPs. This fundamental research provides guidance for designing and manipulating the plasmonic properties in tellurite glass for photonics research and applications.

Advances in Reversible Luminescence Modification and Applications of Inorganic Phosphors Based on Chromism Reaction

AbstractThe reversible luminescence modification of inorganic phosphors has emerged as a promising field, enabling innovative applications such as optical memory, multiple anti‐counterfeiting, and photoswitches. Traditional luminescence modulation techniques, such as core–shell structure design and energy transfer‐related luminescent ions regulation, face challenges in achieving reversible luminescence modification. Chromism induces reversible color changes in materials when stimulated by external fields such as electricity, heat, and light. Combining chromism with luminescence enables the creation of chromism‐driven reversible luminescence manipulation in a single material. This review summarizes recent advances in reversible luminescence modification of inorganic phosphors based on chromism reaction and highlights their potential applications in optical data storage, fingerprint acquisition, and anti‐counterfeiting areas. The potential prospective research directions are also discussed and the challenges and opportunities of chromism‐based reversible luminescent materials are presented for further extended applications.

Syntheses, structures and photophysical properties of Ni/Co[sbnd]Ln coordination polymers

The new Ni/Co-Ln coordination polymers (CPs), {[LnNi0.5(2,5-pydc)(ox)(H2O)x]·yH2O}n (Ln = Pr 1, Nd 2, x = 4, y = 2; Gd 3, Tb 4, Dy 5, x = 3, y = 1; 2,5-H2pydc = pyridine-2,5-dicarboxylic acid, H2ox = oxalic acid); {[Er2Ni(2,5-pydc)3(ox)(H2O)4]·2H2O}n6; {[LnCo0.5(2,5-pydc)(ox)(H2O)x]·yH2O}n (Ln = Pr 7, Nd 8, x = 4, y = 2; Tb 9, x = 3, y = 5) were successfully synthesized by the hydrothermal methods, and their crystal structures were characterized by single-crystal X-ray diffraction. With the participation of the auxiliary ligands (ox2−), the main ligands (2,5-pydc2−) adopt four coordination modes and make these polymers exhibit three kinds of crystal structures. CPs 1, 2, 7 and 8 are isomorphous and exhibit 2D layers which are further connected to form the 3D structure by hydrogen bonds. The other four CPs are bridged into the 3D network structure by 2,5-pydc2- and ox2−. All the polymers are characterized by IR spectro, Roman spectro, thermogravimetric analysis and X-ray powder diffraction. The UV–vis–NIR absorption spectra and Vis fluorescence excitation and emission spectra of nine coordination polymers are measured and analyzed. All the CPs show ligand-to-metal charge transfer (LMCT) transition emission of NiII/CoII–ligands, while some of the CPs show weak characteristic luminescence of LnIII ions.

The effect of high temperature aging on fluorescence properties of Eu3+-doped La2(Zr0.7Ce0.3)2O7

Introduction of luminescent rare earth ions into thermal barrier coatings (TBCs) for the study of TBCs failure mechanism is a very effective non-destructive method. In this paper, Eu3+ ions were doped into La2(Zr0.7Ce0.3)2O7 (LZ7C3) to form LZ7C3:Eu fluorescent material using a high-temperature solid-phase synthesis method. By analyzing the physical structure, fluorescence properties and thermophysical properties of LZ7C3:Eu powders synthesized with different Eu3+ dopant concentrations at different temperatures, we determined that a synthesis temperature of 1400 °C, a dopant concentration of 1 mol% are the optimal synthesis conditions for LZ7C3:Eu. Independent LZ7C3:Eu coating was prepared by atmospheric plasma spraying technology, and high temperature aging test was carried out at 1400 °C. The influence of high temperature aging on the 5D0→7F2 energy level transition peak of Eu3+ in LZ7C3 powder and its coating was examined by microscopic emission spectroscopy. The results show that the peak of the 5D0→7F2 energy level transition is red-shifted, and the peak intensity and the full width at half maxima (FWHM) of the powder decrease gradually with the increase of high temperature aging time. The peak of the 5D0→7F2 energy level transition of the coating exhibits a constantly fluctuating tendency of red-shifting and then blue-shifting, and the peak intensity and the FWHM also continue to decrease. High temperature aging has a negative effect on the fluorescence properties of LZ7C3:Eu materials.

Enhanced luminescence and high stability in Gd3+-doped CsPbBr3 perovskite quantum dots glasses for X-ray detection

The highly luminescent CsPbBr3 perovskite quantum dots (PQDs) glass has shown great potential for applications in X-ray radiation. In this study, the synthesis, crystallization behavior, structural photoluminescence (PL), and X-ray excited luminescence (XEL) of new scintillation luminescent ion Gd3+-service behavior studies were conducted to evaluate the effectiveness of the Gd3+-doped PQDs glasses as X-ray scintillators. The direct band gap semiconductor property makes it suitable for successful detection of X-ray radiation and allows for efficient absorption and emission of X-ray photons, leading to enhanced scintillation performance. These findings highlight the potential of Gd3+-doped CsPbBr3 PQDs glasses as promising materials for X-ray scintillation applications.

Highly luminescent ultra-thin films with rare earth for plasmonic applications

Amphiphilic complexes with luminescent rare earth metal ions suitable for Lanmuir-Blodgett (LB) deposition have been synthesized. LB monolayers with closely packed Eu complexes deposited directly on silver demonstrate significant far-field emission in contrast to the theoretical predictions of full quenching. Angular radiation and polarization patterns of the electric and magnetic dipole emission of Eu3+ point to a high excitation efficiency of surface plasmon polaritons. Different luminescent behavior of closely packed emitters in comparison to diluted systems is tentatively attributed to the collective state of emitters in LB layers formed via near-field coupling with surface plasmons.

A chemiluminescence method based on Ce-PA-Tb polymer for rapid determination of difloxacin in aquatic products

Ce-PA-Tb polymer with Ce and Tb as metal ion centers was prepared and applied in chemiluminescence (CL) reaction. The structure and property of Ce-PA-Tb were explored. Ce-PA-Tb combines both the oxidant ion (Ce(IV)) and luminescence ion (Tb(III)). Difloxacin can enhance the CL signal of Ce-PA-Tb-SO32- reaction in acidic medium. Under the optimized affecting factors, a CL method for the selective difloxacin determination was established. The CL intensity showed a good linear relationship from 10.0 to 300.0 μg/L (r = 0.9996) with the limit of detection was 1.1 μg/L. The method with the signal response at 0.5 s and completed the CL process within 10 s. The method was used to determine difloxacin in aquatic products, and the recovery rate was in the range of 88.1%–104.0%. The CL method designed Ce-PA-Tb based is demonstrated to be an excellent tool for difloxacin determination in aquatic products.