Multicolor Luminescence Research Articles

Excitation power-dependent multicolor upconversion in NaLnF4:Er3+ under 1532 nm irradiation for anti-counterfeiting application

Upconversion (UC) materials are renowned for their ability to convert low-energy photons into high-energy ones. The manipulation of parameters allows for the observation of multicolored UC luminescence (UCL) within a single material system. While modulation of multicolored UCL commonly relies on excitation at approximately 980 nm, investigation into multicolored UC materials activated by a 1532 nm excitation source remains comparatively scarce. In this work, we introduce NaLnF4:Er3+ as a novel class of smart luminescent materials. When the power density of a 1532 nm laser increases from 0.5 to 20.0 W/cm2, the emission peak positions remain unchanged, but the red-to-green (R/G) ratio decreases significantly from 18.82 to 1.48, inducing a color shift from red to yellow and ultimately to green. In contrast, no color variation is observed when NaLnF4:Er3+ is excited with a 980 nm laser at different power densities. This power-dependent multicolored UCL of NaLnF4:Er3+ excited at 1532 nm can be attributed to the competitive processes of upward pumping and downward relaxation of electrons on the 4I9/2 level of Er3+. By utilizing the unique UC characteristics of NaLnF4:Er3+, its potential utility in anti-counterfeiting applications is demonstrated. Our research highlights the distinctive optical properties of NaLnF4:Er3+ and provides novel insights into the use of luminescent materials in optical anti-counterfeiting technologies.

Synthesis of NaYbF4:Er nanocrystals with controllable size, morphology, and multicolor upconversion luminescence for Anticounterfeiting applications

The dopant concentration of lanthanide ions plays one of the critical roles to manipulate size/morphology, photon population pathway, or luminescence color/intensity in upconversion nanoparticles (UCNCs), which have a significant effect on their application developments. Herein, a strategy is demonstrated for simultaneous size, morphology and multicolor luminescence tuning in the single doped lanthanide activator Er3+ ion system through simply tuning the concentration of Er3+ ions. The doping of different Er3+ ion amounts in NaYbF4:Er nanocrystals can control nanoparticle size (from several hundreds to tens of nanometers) and morphology. Moreover, multicolor upconversion luminescence involving green, yellow, orange and red can be obtained in the NaYbF4:Er UCNCs by changing the excitation power density of 980 nm laser. Mechanistic studies reveal the size and morphology evolution process as well as saturation/cross relaxation effects induced tunable multicolor emissions. These nanocrystals have demonstrated promising potential applications in anticounterfeiting. Our results not only provide a simple and feasible route for simultaneous size/morphology control and multicolor upconversion luminescence tuning, but also can further expand the utility of UCNCs in the frontier applications ranging from optical encoding to information security.

Laponite-activated AIE supramolecular assembly with modulating multicolor luminescence for logic digital encryption and perfluorinated pollutant detection

Recently, the non-covalently activated supramolecular scaffold method has become a prominent research area in the field of intelligent materials. Here, the inorganic clay (LP) promoted the AIE properties of 4,4′,4″,4‴-(ethene-1,1,2,2-tetrayltetrakis(benzene-4,1-diyl))tetrakis(1-ethylpyridin-1-ium) (P-TPE), showing an astonishing 42-fold enhancement of the emission intensity of the yellow-green luminescence and a 34-fold increase of the quantum yield via organic-inorganic supramolecular strategy as well as the efficient light-harvesting properties (energy transfer efficiency up to 33 %) after doping with the dye receptor Rhodamine B. Furthermore, the full-color spectral regulation, including white light, was achieved by adjusting the ratio of the donor to the acceptor component and co-assembling with the carbon dots (CD). Interestingly, this TPE-based non-covalently activated full-color supramolecular light-harvesting system (LHS) could be achieved not only in aqueous media but also in the hydrogel and the solid state. More importantly, this panchromatic tunable supramolecular LHS exhibited the multi-mode and quadruple digital logic encryption property as well as the specific detection ability towards the perfluorobutyric acid and the perfluorobutanesulfonic acid, which are harmful to human health in drinking water. This result develops a simple, convenient and effective approach for the intelligent anti-counterfeiting and the pollutant sensing.

Thermally stable Tb3+/Sm3+-doped Lu2O2S phosphors with tunable multicolor luminescence under light and X-ray excitation

Lu2O2S has high density, high melting temperature, and favorable thermal stability, making it an excellent matrix material for rare earth luminescence and X-ray sensitization screens. However, achieving high quality fluorescent powders with high crystal quality on a large scale is still challenging. By employing an optimized solid phase approach, Lu2O2S:Tb3+/Sm3+phosphors with a hexagonal shape and uniform particle size and showing high crystallization have been successfully synthesized. Spectral analysis reveals energy interaction between Sm3+ and Tb3+ in the Lu2O2S system (multistage interaction), indicated by spectral overlap, relative changes in luminescence intensity, and lifetime decay. By changing the excitation wavelength and dopant concentration, multicolor phosphors such as yellow-–green, orange–red, and orange–yellow could be created. Temperature-dependent emission spectroscopy shows that the system shows good luminescence performance even at high temperatures. X-ray excitation spectroscopy further confirm that the phosphors emit different colors (yellow, green and red) depending on the doping concentrations of Tb3+ and Sm3+ ion, indicating that the system has wide application potential in color displays and other relevant fields.

Modulation of photoluminescence properties by poling and quenching strategy in rare earth ions doped Na1/2Bi1/2TiO3-based ceramics

With the continuous development of the society, optical ceramics are more and more widely used in daily life. In this work, the photochromic (PC) and photoluminescence (PL) properties of Na1/2Bi1/2TiO3 (NBT)-based ceramics doped with different rare-earth elements (Er, Eu, and Ho) are investigated. It is found that NBT-Er\\Eu and NBT-Er\\Ho ceramics have good up-conversion PL properties under 980 nm laser excitation. After poling and quenching treatments, the PL intensity of NBT-Er\\Eu ceramics increases by 1.5 and 11.7 times, respectively, and the NBT-Er\\Ho ceramics increases by 5.1 and 3.6 times, respectively. Besides, the rare-earth ions doped NBT-based ceramics exhibit fast PC response and self-bleaching behavior. In addition, multicolor luminescence behavior (from bright green to orange-yellow) is obtained in NBT-Er\\Eu ceramics, suggesting the potential application of this material in the field of optical information storage and optical anti-counterfeiting. Therefore, this work not only provides a new PC material exhibiting fast PC response and self-bleaching behavior, but also develops new universal strategies to modulate PL properties without changing the composition.

Fabrication of Translucent and Chemically Durable Crystal‐Glass Composite with Multicolor Persistent Luminescence

AbstractLong persistent luminescence materials (LPLMs) are promising candidates for various photonic applications, owing to their ability to store light. In spite of advancements in exploring of new LPLMs, the fabrication of transparent centimeter‐sized LPLMs with pre‐designed shapes, high productivity, long afterglow multicolor luminescence, and high chemical stability, is still challenging. Here, high‐throughput manufacture of translucent crystal‐glass composites via a classical injection molding (IM) technique is demonstrated, in which persistent phosphors (PPs)‐amorphous silica nanoparticles‐polymer composites are molded into different shapes then thermally treated at elevated temperatures to obtain glass composites with embedded PP particles and customized shapes. The structural characterizations endorse that the PP particles are preserved during high temperature sintering, and the resultant crystal‐glass composites combine the unique benefits of both PPs and silica glass. Remarkably, the total production time to manufacture 100 pieces of centimeter‐sized crystal‐glass composites is 35 h, thus enabling high‐throughput production of glass composite articles by the IM method. In addition, the injection molded crystal‐glass composites demonstrate long afterglow multicolor luminescence and ultrahigh chemical durability. This study provides a massive production strategy for the fabrication of translucent and stable multicolor persistent luminescent objects with customized shapes, which can be used in numerous applications.

Long lifetimes white afterglow in slightly crosslinked polymer systems

Intrinsic polymer room-temperature phosphorescence (IPRTP) materials have attracted considerable attention for application in flexible electronics, information encryption, lighting displays, and other fields due to their excellent processabilities and luminescence properties. However, achieving multicolor long-lived luminescence, particularly white afterglow, in undoped polymers is challenging. Herein, we propose a strategy of covalently coupling different conjugated chromophores with poly(acrylic acid (AA)-AA-N-succinimide ester) (PAA-NHS) by a simple and rapid one-pot reaction to obtain pure polymers with long-lived RTPs of various colors. Among these polymers, the highest phosphorescence quantum yield of PAPHE reaches 14.7%. Furthermore, the afterglow colors of polymers can be modulated from blue to red by introducing three chromophores into them. Importantly, the acquired polymer TPAP-514 exhibits a white afterglow at room temperature with the chromaticity coordinates (0.33, 0.33) when the ratio of chromophores reaches a suitable value owing to the three-primary-color mechanism. Systematic studies prove that the emission comes from the superposition of different triplet excited states of the three components. Moreover, the potential applications of the obtained polymers in light-emitting diodes and dynamic anti-counterfeiting are explored. The proposed strategy provides a new idea for constructing intrinsic polymers with diverse white-light emission RTPs.

One-step preparation and dual mode luminescence anti-counterfeiting application of LiYF4: Yb3+, Ho3+, Ce3+@ carbon quantum dot composite materials

In the field of fluorescent anti-counterfeiting, materials with single luminous mode are easy to be forged, which cannot meet the current anti-counterfeiting requirements. Currently reported bimodal light-emitting materials usually require multi-step and tedious synthesis steps. In this paper, LiYF4: Yb3+, Ho3+, Ce3+ upconversion micron particles (UCMPs)/carbon quantum dots (CDs) composite materials were prepared by one-step hydrothermal method, which greatly simplified the composite process of CDs and UCMPs. The upconversion wavelength (from green light to red light excited by 980 nm) can be achieved by changing the doping concentration of Ce3+ ions. Through the combination of CDs and UCMPs, an obvious dual mode luminescence phenomenon was achieved. Finally, screen printing was used to produce a clover pattern, which realized multi-color luminescence under 365 nm and 980 nm excitations respectively. The new fluorescence anti-counterfeiting composites, which uses simple and environmentally friendly one-step synthesis process, is expected to promote the development of fluorescence anti-counterfeiting field.

Organic Cocrystal Alloys: From Three Primary Colors to Continuously Tunable Emission and Applications on Optical Waveguides and Displays.

Multicolor luminescence of organic fluorescent materials is an essential part of lighting and optical communication. However, the conventional construction of a multicolor luminescence system based on integrating multiple organic fluorescent materials of a single emission band remains complicated and to be improved. Herein, organic alloys (OAs) capable of full-color emission are synthesized based on charge transfer (CT) cocrystals. By adjusting the molar ratio of electron donors, the emission color of the OAs can be conveniently and continuously regulated in a wide visible range from blue (CIE: 0.187, 0.277), to green (CIE: 0.301, 0.550), and to red (CIE: 0.561, 0.435). The OAs show analogous 1D morphology with smooth surface, allowing for full-color waveguides with low optical-loss coefficient. Impressively, full-color optical displays are easily achieved through the OAs system with continuous emission, which shows promising applications in the field of optical display and promotes the development of organic photonics.

Construction of active-inert core–shell structured nanocrystals for broad range multicolor upconversion luminescence

Rare earth doped up-conversion luminescent nano-materials exhibit abundant emission colors under suitable excitation condition. In this work, NaYF4:Er/Ho@NaYF4 and NaYbF4:Tm@NaYF4 nanoparticles were synthesized by co-precipitation method. The pure red emission can be realized by the designed NaYF4:Er/Ho@NaYF4 nanocrystals and the R/Gs reach 23.3 and 25 under excitations of 980 and 1550 nm lasers, respectively. The R/G declines as the power increasing with the emission color changing from red to yellow, which is due to the quick saturation of the energy levels, radiating red emissions. Meanwhile, the emission intensity of NaYbF4:Tm@NaYF4 nanocrystals increases by 58.3 folds after encasing the inert shell NaYF4 and the CIE color coordinate reaches (0.1646, 0.0602) under 980 nm laser excitation. Furthermore, broad range multicolor from blue to red and yellow up-conversion emissions is achieved by mixing NaYF4:Er/Ho@NaYF4 and NaYbF4:Tm@NaYF4 nanocrystals, which could be applied to colorful displaying, security anti-counterfeiting and information coding.

Thermal Activated Reversible Phosphorescence Behavior of Solid Supramolecule Mediated by β‐Cyclodextrin

AbstractA reversible solid thermally responsive deep‐blue pure organic room temperature phosphorescent material is constructed by terephthalic acid (PPA), β‐cyclodextrin (β‐CD), and poly(vinylalcohol) (PVA). Attributed to the host‐guest interaction of β‐CD to isolate PPA chromophore and the rigid environment offered by hydrogen bonds to suppress the nonradiative decays, amorphous supramolecular assembly PPA‐CD/PVA not only induces a deep‐blue phosphorescence at 410 nm that differing from traditional PPA derivatives with green emission but also enhances the quantum yield up to 30.52%. Uncommonly, this film exhibits a unique reversible thermal stimulation response property with blue and cyan phosphorescence color transitions because heating can destroy the binding behavior between β‐CD and PPA, resulting in redshift phosphorescence emission from PPA stacking. Additionally, with the incorporation of Rhodamine B (RhB) or Sulforhodamine 101 (SR101) into the supramolecular film, color‐tunable phosphorescence from blue to white, yellow, and red relying on the thermal stimulation is realized through triplet‐to‐singlet Förster resonance energy transfer (TS‐FRET) platform. These thermochromic phosphorescence materials are successfully applied in multilevel anticounterfeiting and information encryption, which provides a new simple approach for temperature‐responsive TS‐FRET multicolor luminescence supramolecular materials.

Multi-mode excited upconversion and downshifting of Ho3+/Yb3+ doped lead-free double perovskite Cs2NaBiCl6 for anti-counterfeiting and thermometry

Rear earth(RE)-doped halide perovskite has generated as an amazing optical material for multicolor luminescence. Free-lead halide double perovskites have attracted interesting because of their non-toxicity and higher instability. Here, RE3+ doped chloride-based double perovskite phosphors are reported. A series of heavy concentration Ho3+/Yb3+ doped Cs2NaBiCl6(CNBC) phosphors are prepared with a solvothermal route. The band structure of CNBC is calculated through density functional theory (DFT). The luminescence properties of CNBC:Ho3+ and CNBC:Ho3+/Yb3+ are investigated through upconversion(UC) and downshifting(DS) processes. From CNBC:Ho3+, the brightness orange, deep red and pale green lights are achieved under excitation at 365, 452 and 980 nm. The multicolor emissions of CNBC:Ho3+ are used to multimode fluorescent anti-counterfeiting. Comparing with CNBC:Ho3+ samples, the UC emission intensity of CNBC:Ho3+/Yb3+ are dramatically enhanced. The brightness green light can be seen by naked eyes under super lower power pumping(∼10 mW). The temperature sensing properties of CNBC:Ho3+/Yb3+ phosphor are investigated systematically based on the luminescence intensity ratio(LIR) of thermally coupled levels(TCLs)(5F1/5G6,5F2,3/3K8) and non-TCLs(5F4/5S2,5F5). The maximum relative sensitivity(SR) reaches 5.089% K−1 at 293 K according to the LIR of non-TCLs. The work will broaden the application field of RE3+-doped free-lead perovskite such as anti-counterfeiting and thermometry.

Multisite Fine-Tuning in Hybrid Cadmium Halides Enables Wide Range Emissions for Anti-Counterfeiting.

Achieving tunable emissions spanning the spectrum, from blue to near-infrared (NIR) light, within a single component is a formidable challenge with significant implication, particularly in tailoring multicolor luminescence for anti-counterfeiting purposes. In this study, we demonstrate a broad spectrum of emissions, covering blue to red and extending into NIR light in [BPy]2CdX4 : xSb3+ (BPy=Butylpyridinium; X=Cl, Br; x=0 to 0.08) through precise multisite structural fine-tuning. Notably, the multicolor emissions from [BPy]2CdBr4 : Sb3+ manifest a distinctive pattern, transitioning from blue to yellow in tandem with the host [BPy]2CdBr4 and further extending from yellow to NIR with its homologous [BPy]2CdCl4 : Sb3+, resulting in the simultaneous presence of intersecting and independent emission colors. Detailed modulation of chemical composition enables partial luminescence switching, facilitating the creation of diverse patterns with multicolor luminescence by employing [BPy]2CdX4 : xSb3+ as phosphors. This study for the first time successfully implements several groups of tunable emission colors in a single matrix via multisite fine-tuning. Such an effective strategy not only develops the specific relationships between tunable emissions and adjustable compositions, but also introduces a cost-effective and straightforward approach to achieving unique, high-level, plentiful-color and multiple-information-storage labels for advanced anti-counterfeiting applications.

Multisite Fine‐Tuning in Hybrid Cadmium Halides Enables Wide Range Emissions for Anti‐Counterfeiting

AbstractAchieving tunable emissions spanning the spectrum, from blue to near‐infrared (NIR) light, within a single component is a formidable challenge with significant implication, particularly in tailoring multicolor luminescence for anti‐counterfeiting purposes. In this study, we demonstrate a broad spectrum of emissions, covering blue to red and extending into NIR light in [BPy]2CdX4 : xSb3+ (BPy=Butylpyridinium; X=Cl, Br; x=0 to 0.08) through precise multisite structural fine‐tuning. Notably, the multicolor emissions from [BPy]2CdBr4 : Sb3+ manifest a distinctive pattern, transitioning from blue to yellow in tandem with the host [BPy]2CdBr4 and further extending from yellow to NIR with its homologous [BPy]2CdCl4 : Sb3+, resulting in the simultaneous presence of intersecting and independent emission colors. Detailed modulation of chemical composition enables partial luminescence switching, facilitating the creation of diverse patterns with multicolor luminescence by employing [BPy]2CdX4 : xSb3+ as phosphors. This study for the first time successfully implements several groups of tunable emission colors in a single matrix via multisite fine‐tuning. Such an effective strategy not only develops the specific relationships between tunable emissions and adjustable compositions, but also introduces a cost‐effective and straightforward approach to achieving unique, high‐level, plentiful‐color and multiple‐information‐storage labels for advanced anti‐counterfeiting applications.

Colorful Room‐Temperature Phosphorescence Including White Afterglow from Mechanical Robust Transparent Wood for Time Delay Lighting

The preparation of mechanical robust organic room‐temperature phosphorescence (RTP) materials especially with white afterglow is attractive but rarely reported. Herein, a method to produce mechanical robust colorful RTP transparent wood (PTW) by infiltrating delignified wood with poly (vinyl alcohol) solutions containing arylboronic acids with various π conjugations is reported. The doubly rigid environment provided by the B─O covalent bonds and hydrogen bonds can stabilize the triplet excitons, leading to a ultralong lifetime of up to 2.13 s and excellent RTP emission stability (without obviously quenching over a month) of the target PTW. Besides, as a promising structural material for optical applications, the PTW shows combined advantages of multicolored persistent luminescence (from blue to green and then to red), good optical transmittance (≈90%), and striking mechanical strength (≈154 MPa). More importantly, by introducing appropriate amount of fluorescent dye rhodamine 6 G to the PTW with blue afterglow, white afterglow with a lifetime of 1.85 s is successfully achieve through triplet‐to‐singlet Förster resonance energy transfer. The PTW can function as afterglow window, anticounterfeiting label, and time delay lighting. This success paves the way for the development of mechanical robust, ecofriendly, and practical RTP materials.

Multi-color luminescent material with Mn2+/Mn4+ non-stoichiometric ratio doped octahedra and its anti-counterfeiting applications

Mn ions in different valence states can emit light of different colors in an octahedral coordination environment, which is conducive to the development of a single matrix with multi-color luminescence and applications in the field of anti-counterfeiting. The dual mode multi-color luminescent material CaSb2O6: Mn has been successfully synthesized using a single Mn source in the atmosphere. The CaSb2O6 matrix itself can also absorb 285 nm UV light, emit blue light, and show a long afterglow phenomenon. Both Mn4+ and Mn2+ ions will appear in the [SbO6] octahedra, whether the Mn source adopts MnCO3 or MnO2. The Mn4+ ion exhibits red emission upon UV excitation at 347 nm. The Mn2+ ion can emit a bright green light at 285 nm excitation while exhibiting a long afterglow phenomenon. In this study, the Mn2+ doped octahedron showed unique green emission and broadens the range of its photoluminescence (PL) wavelength. The performance of the material's long afterglow properties on the digital codes demonstrates its potential for dynamic anti-counterfeiting.

Efficient Single-Phase Tunable Dual-Color Luminescence with High Quantum Yield Greater than 100% for Information Encryption and LED Applications.

In modern society, the investigation of highly efficient photoluminescent bulk materials with excitation-induced tunable multicolor luminescence and multiexciton generation (MEG) is of great significance to information security and the application of optoelectronic devices. In this study, two bulk Cu-based halide crystals of (C4H10NO)4Cu2Br5·Br and (C4H10NO)4Cu2I5·I·H2O, respectively, with one-dimensional structures were grown by a solvent evaporation method. Unexpectedly, (C4H10NO)4Cu2I5·I·H2O displayed excitation-induced tunable dual-color luminescence; one band is a brilliant green-yellow emission centered at 547 nm with a high photoluminescence quantum yield (PLQY) of up to 169.67%, and the other is a red emission at 695 nm with a PLQY of 75.76%. Just as importantly, (C4H10NO)4Cu2Br5·Br exhibits a strong broadband green-yellow emission at 561 nm under broad band excitation ranging from 252 to 350 nm, a long PL decay lifetime of 106.9 μs, and an ultrahigh PLQY of 198.22%. These materials represent the first two examples of 1D bulk crystals and Cu(I)-based halides that have a PLQY exceeding 100%. Combining the unusual luminescence characteristics with theoretical calculations reveals that MEG contributes to the green-yellow emission with ultrahigh PLQY > 100%, and that the red emission can be ascribed to [Cu2I5]3- cluster-centered emission. Additionally, an information encryption method was designed based on the Morse Code. The high luminescence characteristics of LED devices fabricated using the (C4H10NO)4Cu2Br5·Br and (C4H10NO)4Cu2I5·I·H2O crystals appear to lead to promising applications in solid-state lighting. This work extends the catalog of high-performance luminescent materials and also promotes application prospects of low-dimensional copper-based halides in optoelectronics.

Strategies for Constructing Macrocyclic Arene-Based Color-Tunable Supramolecular Luminescent Materials.

Over the past decades, supramolecular luminescent materials (SLMs) have attracted considerable attention due to their dynamic noncovalent interactions, versatile functions, and intriguing applications in many research fields. From construction to application, great efforts and progress have been made in color-tunable SLMs in recent years. In order to realize multicolor luminescence, various design strategies have been proposed. Macrocyclic chemistry, one of the brightest jewels in the field of supramolecular chemistry, has played a crucial role in the construction of stimuli-responsive and emission-tunable SLMs. Moreover, the flexible and tunable conformation and multiple noncovalent complexation sites of the macrocyclic arenes (MAs) afford a new opportunity to create such dynamic smart luminescent materials. Inspired by our reported work on the color-tunable supramolecular crystalline assemblies modulated by the conformation of naphth[4]arene, this Concept provides a summary of the latest developments in the construction of color-tunable MA-based SLMs, accompanied by the various construction strategies. The aim is to provide researchers with a new perspective to construct color-tunable SLMs with fascinating functions.

Realizing Red Mechanoluminescence of ZnS: Mn2+ Through Ferromagnetic Coupling

AbstractSelf‐recoverable mechanoluminescence (ML) is becoming a novel technology widely used in the fields of sensing, display, and artificial intelligence. The dominant ML material, ZnS: Mn2+, is reported to solely present a yellow emission color, which limits the applications of self‐recoverable ML materials to a large extent. Herein, an effective strategy to extend the ML emission range of ZnS: Mn2+ by the ferromagnetic coupling of Mn2+ ions are reported. Under the thermal carbon‐reduction atmosphere (TCRA), the emission ranges of ML, photoluminescence (PL), and persistent luminescence spectra of ZnS: Mn2+ phosphors are all successfully broadened from yellow to red. Furthermore, as for the PL and ML intensities of ZnS: Mn2+, they are intensified to 1.76 and 3.23 folds larger under the TCRA treatment than those in pure nitrogen, respectively. Various spectra and magnetic test results reveal that the red emission bands of ZnS: Mn2+ @TCRA phosphors originate from the ferromagnetic coupling of Mn2+ ions. This study is the first to realize strong red emission and tunable multicolor luminescence in the conventional ZnS‐based phosphors, which introduces opportunities for discovering the multiband emissions of Mn2+ ion in other compounds. Brightly multicolored ZnS: xMn2+ @TCRA elastic films have been fabricated to demonstrate their anti‐counterfeiting and security applications.

Multiple optical thermometry and dynamic anti-counterfeiting based on multicolor luminescence of SrY2O4:Bi3+,Er3+ phosphor

Multifunctional materials with optical temperature sensing and anti-counterfeiting properties have vast application prospects in our daily life, but the development of them still faces huge challenges. Herein, a novel SrY2O4:Bi3+,Er3+ phosphor with multicolor luminescence was synthesized triumphantly. Stimulated by different ultraviolet (UV) lights, the sample exhibits blue or green emissions, while emits yellow up-conversion luminescence under 980 nm laser irradiation. Interestingly, abnormal thermal quenching and thermal stimulation enhanced persistent luminescence are realized in SrY2O4:Bi3+,Er3+. Benefiting from the distinct responses of Bi3+ and Er3+ luminescence to temperature, thermochromism is verified when excited by UV or 980 nm light. Furthermore, the color shift from yellow-green to dark yellow is seen as the 980 nm laser power density reduces or the distance between laser source and the sample increases. Based on the luxuriant luminescence properties, multimode optical temperature sensing and dynamic anti-counterfeiting are constructed. All findings indicate that the multicolor emissive SrY2O4:Bi3+,Er3+ material offers a fresh outline for the exploitation of multiple optical thermometry and anti-counterfeiting.