Enhancement Of Emission Intensity Research Articles

Enhanced photoluminescence in Dy3+/Au co-doped bismuth borosilicate glass

Several optical applications demand for enhanced optical response of rare earth containing glasses. In the present investigation, modification in spectral features with the dispersion of gold nanoparticles in Dy3+ doped bismuth borosilicate glasses is reported. All the glass samples were prepared using conventional melt-quench technique. Prepared glasses were characterised using Fourier transform infrared spectroscopy (FTIR), dilatometery, field emission scanning electron microscopy (FESEM), Uv–Vis–NIR spectroscopy and photoluminescence. Thermal studies carried out using dilatometer confirms the decrease in glass transition after co-doping of gold nanoparticles and Dy3+. Field emission scanning electron microscopy revealed the existence of gold nanoparticles inside the glassy matrix. A marginal change in the values of Judd-Ofelt parameters of glasses is observed after the incorporation of gold nanoparticles. Significant enhancement in emission intensities is observed after the addition of gold nano-particles. The high stimulated emission cross-section (σemi) and radiative transition probability values for prepared glasses confirms their suitability for the fabrication of yellow light laser.

In Situ Turn-On Room Temperature Phosphorescence and Vapor Ultra-sensitivity at Lifetime Mode

Organic room temperature phosphorescence (RTP) systems are rarely reported for vapor phase sensing due to the contradiction between vapor permeability and phosphorescence ability. Till now, almost all reported works are based on ″turn-off″ mode RTP detection by destroying the compact-packaging oxygen-free environment. ″Turn-on″ mode RTP detection owns additional anti-interference capability due to a lower initial RTP background signal, while its realization is even harder. In this research, in situ phosphorescence ″turn-on″ sensing was realized for methamphetamine (MPEA) vapor detection. Based on the formation of aromatic phenolic aldehyde-secondary amine ion pairs with air-stable RTP performance, the fluorescent tri-formyl phenol (TFP) film was converted into a stable RTP state after being exposed to the MPEA vapor, as supported by nuclear magnetic resonance (NMR) and mass spectrometry together with theoretical calculations. The red-shifted absorption and emission, enhanced emission intensity, and 49.7 μs phosphorescence lifetime allowed multiple mode MPEA vapor sensing from chromaticity to fluorescence to phosphorescence. The lifetime mode detection limit reached 0.4 ppt, 5 orders of magnitude lower than the intensity mode detection limit of 20.3 ppb.

Single red upconversion luminescence in β-Ba2ScAlO5: Yb3+/Er3+ phosphor assisted by Ce3+ ions

Recent decades have witnessed an explosion in research devoted to pure upconversion (UC) red emission attractive for bioimaging and anti-counterfeiting. Single-band red UC emission of Er3+ has been implemented in the new β-Ba2ScAlO5: Yb3+/Er3+ phosphor assisted by Ce3+. The red to green integrated intensity ratio reaches up to 430.9. Doping of Ce3+ ions leads to large cross-relaxation probabilities between Er3+ and Ce3+ ions when excited at 980 nm near infrared laser, resulting in suppressing the green emission and enhancing the red emitting level of Er3+. The optimal doping concentration of Ce3+ ions is 0.008 in β-Ba2ScAlO5: Yb3+/Er3+ sample, and a 4.1-fold red emission intensity enhancement was achieved than that of β-Ba2ScAlO5: Yb3+/Er3+ sample without Ce3+ ions. The possible upconversion luminescence (UCL) mechanism is investigated according to absorption spectrum, excitation spectrum, photoluminescence spectrum and upconversion emission lifetime decay spectrum of Yb3+/Er3+/Ce3+ co-doped β-Ba2ScAlO5, which was concluded that the 5d-4f energy transfer and large cross-relaxation probabilities between Er3+ and Ce3+ ions to achieve enhancement of red emission and the super-high ratio of red to green UCL emission integrated intensity. This work can pave a perspective way to obtain new phosphor with single UC red emission for applications in a variety of the fields.

Spectral design in Cr3+-doped NIR phosphors via crystal field modulation

Effective broadband longer-waved (>850 nm) near-infrared (NIR) phosphors are in great demand for diverse applications. Benefitting from photoluminescence tuning of Cr3+-activated phosphor, a sequence of LaSc3-2xCaxSixB4O12(LSCSB): Cr3+ (0 ≤ x ≤ 1.0) phosphors have been designed via regulating the crystal field environment based on non-equivalent co-substitution of Sc3+-Sc3+ by Ca2+-Si4+. The relationship between structural variation, crystal field modulation, luminescence performance, and thermal stability of the LSCSB: Cr3+ (0 ≤ x ≤ 1.0) have been investigated. The structural evolution is induced along with x value, consequently, the phosphors exhibit a tunable emission wavelength toward longer wavelength from 871 nm to 880 nm depending on crystal field engineering, which enriches the NIR phosphor with a longer emission wavelength. Moreover, the photoluminescence behaviors of LSCSB: yCr3+ (x = 0.9) (0.01 ≤ y ≤ 0.13) have been studied in detail. Targeted phosphor LSCSB: 0.09Cr3+ (x = 0.9), with enhanced emission intensity and thermal stability compared with that of LSB: Cr3+, yields a broadband NIR emission centered at 880 nm under 460 nm excitation. The NIR pc-LED, fabricated by combining the LSCSB: 0.09Cr3+ (x = 0.9) with a blue LED chip, exhibits excellent thermal stability and reliability in the practical application process, indicating its potential for the application in blue-pumped NIR pc-LED towards diversified applications. In addition, a consequence of regular pattern has been summarized to provide an efficient approach to design and modulate the Cr3+-doped phosphor with proper luminescence property.

Up-conversion luminescence and optical temperature sensing of Er3+, Yb3+ co-doped Gd2O3 phosphors with different F-/Ln3+

In this work, the Er3+, Yb3+co-doped Gd2O3 phosphors have been prepared through a facile hydrothermal method. The optimum doping concentration of the Er3+, Yb3+ co-doped Gd2O3 phosphors are studied in detail. By studying the samples calcined at different temperatures, the process of grain forming self-assembled structure was revealed. The up-conversion luminescence intensity of the phosphors can be regulated by the ratio of NH4F and lanthanoid nitrate (F-/Ln3+) in the synthesis process. The enhancement of red and green emission intensities can reach 8.0 times, 6.7 times respectively than the sample with F-/Ln3+ = 0.5. In addition, the florescence intensity ratio based on thermally coupled energy levels by the Stark sublevels is also investigated. The maximal absolute sensitivity of optical temperature sensing reaches 1.27% K−1 at 574 K, which is 1.51 times higher than that based on traditional thermally coupled energy levels by Stark levels. Therefore, the results show that this is a useful method to improve the absolute sensitivity of optical temperature sensing and the Er3+, Yb3+ co-doped Gd2O3 phosphors have application potential in high sensitivity optical temperature sensing.

Optical thermometry of Tm3+/Yb3+ Co-doped Ba3Gd2F12 up-conversion glass-ceramic with high sensitivity

In this work, Tm3+/Yb3+ co-doped Ba3Gd2F12 oxyfluoride glass-ceramic was synthesized by the conventional melt-quenching method, and an optical thermometer with high sensitivity was proposed accordingly. The structural and optical properties of Ba3Gd2F12: Tm3+/Yb3+ glass-ceramics were systematically investigated. After crystallization, the enrichment of Tm3+ ions in the Ba3Gd2F12 lattice leads to enhancing emission intensity, the prolonged lifetime of Tm3+ ions, and Stark splitting of emission spectra. The dependence of optical properties of Ba3Gd2F12: Tm3+ glass-ceramics on temperature were explored based on fluorescence intensity ratio of 3F2,3 ​→ ​3H6 and 1G4→3F4 transitions of Tm3+ ions. The maximum value of relative sensitivity SR reaches 1.02% K−1 at 457 ​K. This work indicates that the oxyfluoride glass-ceramic embedded with Ba3Gd2F12: Tm3+/Yb3+ nanoparticles is a candidate material with good performance for optical temperature sensors.

Improvement in Luminescence Intensity of β-NaYF4: 18%Yb3+, 2%Er3+@β-NaYF4 Nanoparticles as a Result of Synthesis in the Presence of Stearic Acid.

The synthesis of upconverting nanoparticles (NPs) is crucial for their spectroscopic properties and further applications. Reducing the size of materials to nano-dimensions usually decreases emission intensity. Therefore, scientists around the world are trying to improve the methods of obtaining NPs to approach levels of emission intensity similar to their bulk counterparts. In this article, the effects of stearic acid on the synthesis of core@shell β-NaYF4: 18%Yb3+, 2%Er3+@β-NaYF4 upconverting NPs were thoroughly investigated and presented. Using a mixture of stearic acid (SA) with oleic acid and 1-octadecene as components of the reaction medium leads to the obtaining of monodispersed NPs with enhanced emission intensity when irradiated with 975 nm laser wavelength, as compared with NPs prepared analogously but without SA. This article also reports how the addition of SA influences the structural properties of core@shell NPs and reaction time. The presence of SA in the reaction medium accelerates the growth of NPs in comparison with the analogic reaction but without SA. In addition, transmission electron microscopy studies reveal an additional effect of the presence of SA on the surface of NPs, which is to cause their self-organization due to steric effects.

A switch-on xanthene-triphenylamine based fluorescent and colorimetric sensor for the detection of ultra-trace Hg2+ in food samples and living cells

A novel colorimetric and fluorescent “switch-on” probe based on xanthene-triphenylamine was developed for detection of Hg2+, which threatens public health, food safety and the environment. The probe displayed superior colorimetric and fluorescent selectivity/sensitivity toward Hg2+ over a series of metal ions via Hg2+-triggered deprotection reaction. Hg2+ induced a ∼18-fold enhancement in emission intensity of probe TXS with yellow fluorescence (λem = 558 nm) and led to distinct color transition from light yellow to blue or yellow under daylight depending on solvent mixture. Detection parameters were optimized and examined for the influence that they exerted on the detection which involved the usage of the Box-Behnken design methodology. The sensing pathway was also examined theoretically by DFT and TD-DFT calculations. The probe was successfully utilized for the detection of Hg2+ in several food and water samples with good recoveries. Cell imaging studies demonstrated that the probe was suitable for Hg2+ detection in live cells.

Selective and swift-responsive “off-on” rhodamine B based chemosensors: Recognition of multi-metal ions, on-site sensing of Fe(III) in water samples and bioimaging in aqueous media

Distinct “off–on” rhodamine B based chemosensors 3',6'-bis(diethylamino)-2-(2-(diethylamino)ethyl) spiro[isoindoline-1,9′-xanthen]-3-one (2a); 3′,6′-bis(diethylamino)-2-(2-(dimethylamino)ethyl) spiro[isoindole-1,9′-xanthen]- 3-one (2b) are synthesized in a facile single-step reaction and characterized by X-ray crystallography, NMR, Mass, and FT-IR techniques. 2a, 2b; selectively detected Fe+3, Sn+2, and Cr+3, in aqueous media over 17 other environmentally relevant cations. Furthermore, 2a, 2b showed high selectivity towards Fe+3 ion with ∼ 62 fold (2a), ∼21 fold (2b) enhanced emission intensity. A prominent pink color, in < 1 min (∼40 s) was detected under naked eye on sensing Fe+3. Enhanced emission was rationalized by natural transition orbital analysis using DFT and TD-DFT methods. Detection limit and binding constant of Fe+3 for 2a and 2b are estimated as 51.25 ppb (73 nM), 40.3 ppb (59.7 nM), and 0.80 × 103 M−1, 4.59 × 103 M−1, each respectively, indicating their efficiency towards Fe+3 sensing. A test strip method was developed for the on-site qualitative detection of target metal ions, and practical applicability was demonstrated by determining the concentration of Fe+3 ion in real water samples. Probes 2a, 2b further tested in human gastric adenocarcinoma (AGS) cell-lines via in-vitro imaging. The increased emission intensity in 2a, 2b on binding to Fe+3 in AGS cells indicate their potentiality as small-molecule based biological fluorescent probes.

Silver(I)-Carbene Bond-Directed Rigidification-Induced Emissive Metallacage for Picric Acid Detection.

A new triphenylamine-based tetraimidazolium salt L was developed for silver(I)-carbene bond-directed synthesis of tetranuclear silver(I) octacarbene ([Ag4(L)2](PF6)4) metallacage 1. Interestingly, after assembly formation, metallacage 1 showed a nine-fold emission enhancement in dilute solution while ligand L was weakly fluorescent. This is attributed to the rigidity induced to the system by metal-carbene bond formation where the metal center acts as a rigidification unit. The enhanced emission intensity in dilute solution and the presence of the triphenylamine core made 1 a potential candidate for recognition of picric acid (PA). This recognition can be ascribed to the dual effect of ground-state charge-transfer complex formation and resonance energy transfer between the picrate and metallacage 1. For metallacage 1, a considerable detection limit toward PA was observed. The use of such metal-carbene bond-directed rigidification-induced enhanced emission for PA sensing is noteworthy.

Study of synthesis mechanism, structural, optical and luminescent properties of bluish-violet rare earth doped KSrVO4: Nd3+ nano powders

In this study, we have developed Nd3+ doped KSrVO4 synthesized via combustion synthesis route. Herein, we report the variation in the lattice parameters and confirmed the orthorhombic phase for the as-synthesized blank and KSr(1-x)VO4: xNd3+ (x = 0.0025 – 0.03) phosphor investigated by powder XRD system. The morphology was procured via SEM and TEM and the elemental analysis was carried out with EDAX. UV–Vis spectroscopy showed the variations in the band gap energy values. The Photoluminescence (PL) spectra shows three sharp peaks in the emission spectra located at 424 nm, 486 nm and 507 nm in the visible spectra. As a function of Nd3+ concentration, it was observed that 0.05 mol% Nd3+ doped nanophosphors exhibit the strongest emission intensity. Concentration quenching is induced mainly due to the energy transfer among nearby neighboring ions. The enhanced emission intensity of the phosphor with doping suggests that it may be used in display applications.

Electron-acceptor density adjustments for preparation conjugated polymers with NIR-II absorption and brighter NIR-II fluorescence and 1064 nm active photothermal/gas therapy

Designing conjugated polymers (CPs) with both efficient second near-infrared wavelength (NIR-II) fluorescence and NIR-II photothermal therapy performance remains a huge challenge, as the introduction of excessively strong electron donor and acceptor units significantly increase non-radiative decay. Herein, we describe an “electron acceptor density adjustment” strategy to address this problem, since a lower electron acceptor density in the conjugated polymer backbone can enhance the radiative rate constant and improve NIR-II fluorescence brightness. We used quaterthiophene (4T) with four repeated thiophene chain units and bithiophene (2 TC) modified with long alkyl side chains to reduce the electron acceptor density in the conjugated polymer backbone. The resultant 1064 nm absorption polymer, TTQ-2TC-4T displayed approximately 7.30-folds enhancement in NIR-II emission intensity compared to that of undoped TTQ-1T at the same mass concentration in toluene solution. Furthermore nanoparticles (TTQ-MnCO NPs) based on TTQ-2TC-4T and CO donors (Mn2(CO)10) were developed to realize NIR-II FI-guided 1064 nm laser-triggered NIR-II PTT/Gas synergistic therapy. The TTQ-MnCO NPs nanoparticles exhibited high photothermal conversion efficiency (η) of 44.43% at 1064 nm and high specific NIR-II fluorescence imaging of the cerebral vasculature of live mice. The in vivo results demonstrate that TTQ-MnCO NPs nanoparticles have excellent PTT/Gas synergistic therapeutic effects in MCF-7 tumor-bearing mice under 1064 nm laser irradiation. This study provides a new approach for optimizing both NIR-II fluorescence and NIR-II photothermal performance of NIR-II absorption conjugated polymers.

The role of nanoparticles concentration in the emission intensity enhancement of the laser-produced aluminum plasma

The nanoparticles-enhanced Laser-Induced Breakdown Spectroscopy (NELIBS) is an attractive technique to achieve the emission intensity enhancement of the LIBS spectrum. In this article, we present a study on the enhancement in the LIBS signals of seven different aluminum spectral lines using silver (Ag) nanoparticles on the surface of the Al target. The intensity enhancement factor of about 2–8 as compared with the conventional LIBS has been realized. The results showed an increase in the enhancement factor with the increasing concentration of the Ag nanoparticles. Plasma parameters, such as excitation temperature was estimated using the Boltzmann plot method whereas, the electron number density was estimated from the Stark broadened Al I lines. An increase in the excitation temperature and electron number density has been observed in NELIBS as compared with the conventional LIBS. Furthermore, the relative concentration of the neutral aluminum atoms estimated from the Boltzmann plot is found to be higher in NELIBS as compared with conventional LIBS. The presence of silver nanoparticles resulted in a better interaction of the laser beam with matter revealing enhanced emission intensity.

Plasmon-mediated exciton-phonon coupling in CdS microbelts

Investigating underlying coupling mechanism between surface plasmons (SPs) and excitons is playing a very important role to achieve higher efficient and more stable excitonic optoelectronic devices. Here, cadmium sulfide (CdS) microbelts sputtered with Au nanoparticles (NPs) have been prepared for exploring the SP-mediated energy coupling effect. The enhancement of excitonic emission intensity and a red-shift of the peaks have been surveyed in the Fabry-Perot (F-P) resonant lasing spectra. The investigation on temperature-dependent photoluminescence (TDPL) spectra from these samples demonstrate that the optical phenomenon can be attributed to the exciton–phonon coupling. The research results will provide a paramount importance of theoretical support for building effective and bright photoelectric devices based on the complex SP materials system.

Manipulating spatial alignment of donor and acceptor in host-guest MOF for TADF.

Thermally activated delayed fluorescence (TADF) was achieved when electron-rich triphenylene (Tpl) donors were confined to a cage-based porous metal-organic framework (MOF) host (NKU-111) composed of electron-deficient 2,4,6-tri(pyridin-4-yl)-1,3,5-triazine (Tpt) acceptor as the ligand. The spatially separated donor and acceptor molecules in a face-to-face stacking pattern generated strong through-space charge transfer (CT) interactions with a small energy splitting between the singlet and triplet excited states (∼0.1 eV), which enabled TADF. The resulting Tpl@NKU-111 exhibited an uncommon enhanced emission intensity as the temperature increased. Extensive steady-state and time-resolved spectroscopic measurements and first-principles simulations revealed the chemical and electronic structure of this compound in both the ground and low-lying excited states. A double-channel (T1, T2) intersystem crossing mechanism with S1 was found and explained as single-directional CT from the degenerate HOMO−1/HOMO of the guest donor to the LUMO+1 of one of the nearest acceptors. The rigid skeleton of the compound and effective through-space CT enhanced the photoluminescence quantum yield (PLQY). A maximum PLQY of 57.36% was achieved by optimizing the Tpl loading ratio in the host framework. These results indicate the potential of the MOFs for the targeted construction and optimization of TADF materials.

Synthesis and properties of Multi-Stimuli responsive Water-Soluble copolymers with high porphyrin content

Water-soluble porphyrins have played an important role and showed potential application value in photodynamic therapy, sensor and aqueous photocatalysis. Most of the reported water-soluble porphyrin polymers have low porphyrin content, which is difficult to give full play to the role of porphyrin. To improve the content of porphyrin in polymers, we introduced the hydrophilic chain into the porphyrin molecule to obtain the hydrophilic porphyrin monomer, and then copolymerized with the hydrophilic monomer N-isopropylacrylamide to obtain the water-soluble copolymers with higher porphyrin content. The prepared porphyrin copolymers aqueous solution also showed responsive behavior to temperature, ionic strength and pH. Firstly, temperature affects the solvability and photophysical properties of copolymers. When heating the temperature above their cloud point, the copolymers chain aggregated, leading to the decreased light transmittance and enhanced emission intensity. Secondly, the copolymer aqueous solution showed responsive behavior to ionic strength. After adding different sodium salts into the copolymer aqueous solution, the changes order of cloud point was completely consistent with the Hofmeister series, and their emission intensity also varied. Finally, the copolymer aqueous solution showed responsive behavior to pH. When the pH of copolymer aqueous solution decreased, the inner nitrogen atoms in porphyrin ring were protonated, resulting in an increase in the cloud point of their aqueous solution. At the same time, the maximum absorption peak gradually red-shifted, and the emission intensity also decreased. Therefore, based on the decrease in fluorescence, the protonated copolymer could be used as photo-thermal conversion materials. The measured photo-thermal conversion efficiency (PCE) of the copolymer in the pH = 1.0 aqueous solution was 25.34%.

A dual-functional chemical sensor for the detection of Cu2+ and Cd2+ based on the photochromic diarylethene

A dual-functional sensor DTF-o with a photochromic diarylethene moiety has been designed and synthesized. Its structure was confirmed and analyzed by NMR and MS. The photochromism and fluorescence photoswitching properties of DTF-o were studied in acetonitrile/water (9:1, v/v) solution. DTF-o could selectively recognize Cu2+ by changing its color from colorless to yellow which was attributed to the metal-to-ligand charge transfer (MLCT) absorption band of metal-ligand cooperation. Meanwhile, DTF-o could also be used to detect Cd2+ through obvious emission intensity enhancement by inhibition of CN isomerization with chelation enhanced fluorescence (CHEF). Finally, DTF-o was successfully used in practical samples and made into test strips to detect Cu2+/Cd2+ with high accuracy.

Enhanced luminescence performances of BaLaMgTaO6:Mn4+ red phosphor by Bi3+, Ca2+ doping for indoor plant lighting supplementary LED

A new perovskite BaLaMgTaO6:Mn4+ (BLMTO:Mn4+) red phosphor was synthesized for the first time via the high-temperature solid-state method. The emission band of the phosphor ranges from 650 to 750 nm, which matches well with the absorption band of PFR and PR. By doping of Bi3+ and Ca2+ ions in the BLMTO:Mn4+ phosphor, a 4.76-fold enhancement in the luminescence emission intensity was achieved. The optimized BLMTO:0.5%Mn4+, 1.5%Bi3+, 2%Ca2+ phosphor exhibited a high quantum efficiency of 65% and a high color purity of 98.1% with the chromaticity coordinate (CIE) at (0.733, 0.267). Finally, a LED device was fabricated with the BLMTO:0.5%Mn4+, 1.5%Bi3+, 2%Ca2+ phosphor for further agricultural lighting, which emits warm white light with a low color temperature of 3549 K. The result indicates that the BLMTO:Mn4+, Bi3+, Ca2+ phosphors have a potential for applications in agricultural cultivations.

Enhanced crystallinity and photoluminescence properties of Yb2+ doped SrSi2O2N2 phosphor for image storage applications

A series of Yb2+ and Dy3+ doped SrSi2O2N2 phosphors with enhanced crystallinity and photoluminescence properties have been successfully synthesized by two-step method using Sr2SiO4 as precursor. It is clearly indicated from XRD results that Yb2+ ions can substitute Sr sites in SrSi2O2N2 crystal and exhibit pure phase and well-crystalline in comparison with the samples prepared by traditional solid-state reaction. The excessive amount of Si3N4 in the reactants promoted the formation of pure SrSi2O2N2 phosphors phase. SrSi2O2N2: Yb2+ phosphors show emission band at 583 nm and the broad excitation peaks located at 308 nm, 384 nm and 447 nm, covering the emission wavelength of NUV and blue chips. Compared with the sample prepared by traditional one-step solid-state reaction method, a dramatic enhancement of photoluminescence emission intensity (∼1.75 times) can be observed for SrSi2O2N2: 0.01 Yb2+ phosphor synthesized by two-step method. Due to the concentration quenching, the luminescence intensity reaches the maximum when doping concentration of Yb2+ ions is 1 mol%, which is identified as the electric dipole-electric dipole interaction. Notably, Yb2+ and Dy3+ co-doped SrSi2O2N2 phosphors with pure phase exhibit a unique thermal-stimulated luminescence property under NUV excitation, indicating the potential application in optical information storage. Furthermore, the mechanism of thermal-stimulated luminescence has been proposed.

Enhancement of red upconversion emission intensity of Ho3+ ions in NaLuF4:Yb3+/Ho3+/Ce3+@NaLuF4 core–shell nanoparticles

The red upconversion emission of Ho3+ ions, in the optical window of biological tissue, exhibits excellent prospects in biological applications. This study aims to enhance the red upconversion emission intensity of Ho3+ ions in NaLuF4:20%Yb3+/2%Ho3+/12%Ce3+ nanoparticles through building different core–shell structures with different excitation wavelengths. A significantly enhanced red upconversion emission with a higher red-to-green ratio was successfully obtained in NaLuF4:20%Yb3+/2%Ho3+/12%Ce3+@NaLuF4 core–shell nanoparticles by introducing the Yb3+ and Yb3+/Nd3+ ions into the NaLuF4 shell, with enhancement of the red emission occurring when Yb3+ and Nd3+ ions in the shell transfer more excitation energy to the Ho3+ ions. Investigation of the red emission enhancement mechanism is based on spectral characteristics and lifetimes. We examined the synergistic effect of dual-wavelength co-excitation NaLuF4:20%Yb3+/2%Ho3+/12%Ce3+ @NaLuF4:10%Yb3+/15%Nd3+ core–shell nanoparticles to establish optimal excitation conditions. It is hoped that this method, using red upconversion emission core–shell nanoparticles with multi-mode excitation, can provide new ways to expand the applications of rare-earth luminescent materials in biomedicine and anti-counterfeiting.