Mechanism Of Luminescence Enhancement Research Articles

Remarkable Plasmonic Enhanced Luminescence of Ce3+doped Lanthanide Downconversion Nanoparticles in NIR‐II Window by Silver Hole‐Cap Nanoarrays

AbstractLanthanide downconversion nanoparticles (DCNPs) have huge potential in biosensing and imaging applications in the NIR‐II window. However, DCNPs inherently suffer from low quantum efficiency, due to low absorption cross‐section and the restricted doping concentration of lanthanide ions. In this work, a combined strategy for downconversion luminescence in the NIR‐II window is investigated by the integration of Ce3+ ions into the conventional NaYF4: Yb3+, Er3+ DCNPs and incorporation of periodic silver hole‐cap coupled Nanoarrays (Ag‐HCNAs) simultaneously. Over two orders of magnitude, luminescence enhancement is achieved by the combination of optimized Ce3+ doping and plasmonic effects, compared to NaYF4: Yb3+, Er3+ DCNPs immobilized on the glass substrate. Moreover, 3D Finite‐Difference Time‐Domain (FDTD) simulations and time‐resolved luminescence measurements are combined to gain important insights into the mechanism of downconversion luminescence enhancement. The results show that there is a large electric field enhancement between the Ag nanoholes and the Ag hemisphere cap at 980 nm (excitation enhancement), while the lifetime shortening at 1525 nm revealed an increased radiative decay rate and enhanced quantum yield (emission rate enhancement). The strategy for downconversion luminescence enhancement demonstrated in this work holds a significant potential for advancing the next generation biosensing and bioimaging based on DCNPs in the NIR‐II window.

Modulated upconversion luminescence of water-dispersed NaErF4@NaYF4 nanoparticles by introducing Tm3+/Ho3+ as energy capture centers under multi-wavelength NIR excitation

Water-dispersed red upconversion nanoparticles (UCNPs) have great application prospects in the biomedical field. Thus, a series of Er3+-based upconversion nanoparticles (Er-UCNPs) with excellent red upconversion luminescence under three-wavelength NIR excitation (808/980/1550 nm) were prepared by a simple thermal decomposition method, and then further functionalized by PAA to achieve good water dispersibility. Compared with NaErF4 bare core, the emission intensity of Er-UCNPs samples doping of 0.5%Tm3+ and 0.5%Ho3+ as energy capture centers was significantly enhanced, and further improved after coating with NaYF4 inert shell. Meanwhile, among all Er-UCNPs@NaYF4 samples, NaErF4@NaYF4 exhibited the highest emission intensity and longest luminescence lifetime due to the efficient suppression of luminescence quenching effect, while NaErF4:0.5%Tm3+@NaYF4 showed highest red luminescence purity owing to the energy transfer process between Tm3+(3H5) and Er3+(4I13/2). The hydrophilic Er-UCNPs@NaYF4@PAA samples still maintained good red luminescence under multi-wavelength excitation. The luminescence enhancement mechanism in Er-UCNPs@NaYF4 was discussed in detail based on spectral characteristics. The as-prepared water-dispersed Er-UCNPs@NaYF4@PAA with bright red luminescence under multi-wavelength NIR excitation will have potential applications in targeted therapy and deep tissue imaging.

Enhancing luminescence of AF2: Ln3+ (A = Ca, Sr; Ln = Eu, Tb) by the use of carbon dots

Lanthanide ions-doped fluoride nanocrystals have excellent application prospect. However, low photoluminescence quantum yield (PLQY) is usually along with lanthanide ions-doped fluoride nanocrystals owing to their low molar absorptivity and narrow absorption band. In order to increase the absorption cross section of Ln3+ in fluoride nanocrystals, a facile synthesis strategy to enhance luminescence of AF2: Ln3+ (A = Ca, Sr; Ln = Eu, Tb) by the use of carbon dots (CDs) has been developed in this work. A series of characterizations including TEM, XRD, FTIR and XPS demonstrated that the CDs have been successfully combined with the surface of AF2: Ln3+ nanocrystals. The combination of CDs has little influence on the microstructure and phase structure of AF2: Ln3+, and CDs@AF2: Ln3+ nanocrystals have uniform and regular shape with cubic phase. CDs are used as a broadband sensitizer and lead to the broadband excitation of Ln3+, resulting in the enhancement around 10-fold of Ln3+ luminescence emission in AF2: Ln3+ nanocrystals after CDs combination. The corresponding PLQY increases almost three times, and the luminescence enhancement mechanism by combining CDs is proposed. In addition, the CDs@AF2: Ln3+ nanocrystals are used to prepare CDs@AF2: Ln3+/PVA films, which exhibits excellent luminescence properties under the excitation of UV light. This work provides a superior method for enhancing the luminescence properties of lanthanide ions-doped nanocomposites and demonstrates practical potential as promising candidates for light-converting thin films.

The effect of annealing temperature on the site occupancy and the persistent luminescence of Mn2+-doped magnesium germanate

Mn2+-doped magnesium germanate (MGO:Mn2+) nanoparticles exhibit persistent luminescence in the near-infrared (NIR) region. The origin of the luminescence is from the Mn2+ d-d transition when Mn2+ occupies an octahedral site in MGO that was previously occupied by Mg2+. MGO has two stable stoichiometric forms: MgGeO3 and Mg2GeO4. The octahedra surrounding the Mg2+ ions in these two structures have different extents of distortion. Previous studies have found that under high temperatures, MgGeO3 could turn into Mg2GeO4. However, when Mg2+ is partially substituted with Mn2+, whether the structural transition follows the same trend as the undoped MGO is unclear. In this work, MGO:Mn2+ with mixed MgGeO3 and Mg2GeO4 is produced by thermal annealing at different temperatures. The photoluminescence intensity and persistent luminescence lifetime are found highly dependent on the annealing temperature and the crystallinities of the MGO host. The site where Mn2+ occupies in MGO with mixed stoichiometries is evaluated using X-ray absorption spectroscopy combined with structure simulation. The distribution of the Mn2+ at different Mg2+ sites can be quantitatively identified. This is further related to the observed optical properties, and the mechanism of luminescence enhancement of high-temperature-treated MGO:Mn2+ is rationalized.

Crystal structure and thermally enhanced photoluminescence in Eu(III) coordination polymers self-assembled from p-nitrobenzoic acid

Luminescent thermal quenching is a very troublesome thing for the practical application of luminescent materials, but also is a very common phenomenon. In theory, artificially reducing the number of quenching group around the luminescent lanthanide ion can effectively enhance the luminescence of lanthanide luminescent materials. In this paper, {[Eu2(NBA)6(H2O)4]∙H2O}n [Eu-NBA, NBA = p-nitrobenzoic acid] coordination polymers containing abundant coordination and interstitial water molecules were synthesized via hydrothermal methods. The chemical composition, crystal structures, and thermal stability of Eu-NBA coordination polymers were systemically investigated by Frontier-transfer infrared (FTIR) spectra, single-crystal X-ray diffraction and thermogravimetric analysis. X-ray diffraction analysis results revealed that Eu-NBA coordination polymers were crystallized into one-dimensional (1D) chain structures, where the adjacent Eu3+ ions were linked together by bidentate and/or tetradentate bridging carboxylate groups of the NBA ligands. The temperature-dependent photoluminescence spectra revealed that the shape and intensity of the luminescence spectra strongly depended on the coordination environment around Eu3+, and significant luminescent thermal enhancement was observed. These experimental results provided useful theoretical support for further understanding of the luminescence enhancement mechanism of lanthanide coordination polymers.

Post-Synthetic Modification of Zr-based Metal-Organic Frameworks with Imidazole: Variable Optical Behavior and Sensing.

UiO-66-NH2 -IM, a fluorescent metal-organic framework (MOF), was synthesized by post-synthetic modification of UiO-66-NH2 with 2-imidazole carboxaldehyde via a Schiff base reaction. It was examined using various characterization techniques (PXRD, FTIR, NMR, SEM, TGA, UV-Vis DRS, and photoluminescence spectroscopy). The emissive feature of UiO-66-NH2 -IM was utilized to detect volatile organic compounds (VOCs), metal ions, and anions, such as acetone, Fe3+ , and carbonate (CO3 2- ). Acetone turns off the high luminescence of UiO-66-NH2 -IM in DMSO, with the limit of detection (LOD) being 3.6 ppm. Similarly, Fe3+ in an aqueous medium is detected at LOD=0.67 μM (0.04 ppm) via quenching. On the contrary, CO3 2- in an aqueous medium significantly enhances the luminescence of UiO-66-NH2 -IM, which is detected with extremely high sensitivity (LOD=1.16 μM, i. e., 0.07 ppm). Large Stern-Volmer constant, Ksv , and low LOD values indicate excellent sensitivity of the post-synthetic MOF. Experimental data supported by density functional theory (DFT) calculations discern photo-induced electron transfer (PET), resonance energy transfer (RET), inner filter effect (IFE), or proton abstraction as putative sensing mechanisms. NMR and computational studies propose a proton abstraction mechanism for luminescence enhancement with CO3 2- . Moreover, the optical behavior of the post-synthetic material toward analytes is recyclable.

Upconversion luminescence enhancement and color modulation in Yb3+/Er3+/Ln3+ (Ln = Tm, Ho) tri-doped YF3 microrods

Intelligent regulation of energy transfer process among different rare earth ions doped in the matrix is an effective strategy to realize high-performance upconversion (UC) luminescence. Based on this, wheat ears like Yb3+/Er3+/(Tm3+, Ho3+) triple doped YF3 microrods were fabricated via hydrothermal method, and the morphology, crystal structure, UC luminescence performance dependent on Tm3+/Ho3+ doping concentrations were studied. By comparing with the Yb3+, Er3+ co-doped YF3 microrods, the UC luminescence intensity is enhanced in Yb3+/Er3+/(Tm3+, Ho3+) triple doped YF3 samples due to the cross relaxation processes between Er3+ and Tm3+/Ho3+. Moreover, red emission is enhanced more significantly than green emission in YF3: Yb3+, Er3+, Tm3+, which is contrary to that in YF3: Yb3+, Er3+, Ho3+. The possible energy transfer upconversion mechanism involved is discussed in detail. Meanwhile, an adjustable emission color is easy to achieve via altering the doped Er3+/Tm3+/Ho3+ ion concentration. These studies on the UC luminescence enhancement mechanism of Yb3+/Er3+/(Tm3+, Ho3+) triple doped YF3 microrods are expected to provide a reference for the development of high-efficiency luminescent materials.

Ab Initio Site‐Selective Occupancy and Luminescence Enhancement in Broadband NIR Emitting Phosphor Mg7Ga2GeO12:Cr3+

AbstractCr3+ activated near‐infrared (NIR) phosphors are getting unprecedented attention to fabricate the broad band NIR light emitting diodes (NIR‐LEDs) for nondestructive detection, bio‐imaging, and night vision. However, it remains a major challenge to obtain ultrabroadband NIR emitting phosphor with excellent quantum yield (QY). Here, a broadband NIR emitting phosphor Mg7Ga2GeO12:Cr3+ (MGGO: Cr3+) ranging from 600 to 1300 nm with an outstanding QY (93%) and large full width of half maximum (FWHM = 226 nm) is developed, in which the site occupancy tendency of Cr3+ in MGGO host is discussed in detail through combining the structure optimization and the first‐principles theory calculation with luminescent properties at low temperature. After that, the emission intensity of MGGO:Cr3+ is improved through partial substitution of Mg2+ by alkaline‐earth ions Ca2+, Sr2+, or Ba2+, and the luminescence enhancement mechanism is also investigated. Furthermore, the NIR pc‐LED device is fabricated by combining 450 nm blue LED chip with the brightest phosphor MGGO:Cr3+/Ba2+, and its potential applications are evaluated in the field of nondestructive detection, night vision, and bio‐imaging.

Enhanced luminescence of Mn4+ equivalently doped fluoride phosphors by reducing defects and impurities

The Mn4+-equivalently doped fluoride has red emission with high color purity. Here, the luminescence of the Mn4+-equivalently doped fluoride K2TiF6:Mn4+ (KTF:Mn4+) is significantly enhanced by the NH4+ doping strategy with a 2.27 times increase in luminescence intensity and a slight enhancement in decay time. The mechanism of luminescence enhancement is attributed to lattice distortion caused after the substitution of K+ by NH4+, which improves the stability of Mn4+ and reduce the number of defects and impurities. The prototype WLED with high CRI (Ra = 90.4), the high luminous efficiency of 112 lm/W and low CCT (2836 K) are obtained by using the optimal K2TiF6:Mn4+,NH4+ (KTF:Mn4+, NH4+) as the red light component. Some important luminous performances of the prototype WLEDs barely varied as the drive current was increased from 20 to 100 mA. These results demonstrate that the Mn4+/ NH4+ co-doped KTF is well suited for the fabrication of highly stable WLEDs.

Nucleic Acid Hybridization Enhanced Luminescence for Rapid and Sensitive RNA and DNA Based Diagnostics.

Long-lived emissive nucleic acid probes are widely used in biochemical analysis due to their programmable structures, high signal-to-background ratio, and high sensitivity. Homogeneous detection based on long-lived emissive nucleic acid probes is often achieved through Förster resonance energy transfer (FRET), which suffers from the limitation of a narrow effective distance range. Herein, a new strategy of accessing nucleic acid hybridization-responsive luminescent probes is presented. The photoluminescence (PL) of a Lumi4-Tb complex internally modified with DNA is switched on by nucleic acid hybridization, after which the PL is increased up to 20 times. PL lifetime analysis revealed a possible mechanism of luminescence enhancement. Due to the flexibility of single-stranded nucleic acid chains, the bases and phosphate groups can coordinate with the Tb(III), which reduces the stability of the Tb complex and results in weak PL. After hybridization, the rigid double helix structure suppresses the coordination between Tb(III) and the bases or phosphate groups, causing luminescence enhancement. As the DNA sequence can be freely designed, an array of probes for different DNA or RNA targets can be created with the same Tb complex. Moreover, the novel probe design can afford pM detection limits of DNA or RNA without any nucleic acid amplification and exhibits great potential for nucleic acid detection in clinical diagnosis.

Highly Photoluminescent Monolayer MoS2 and WS2 Achieved via Superacid Assisted Vacancy Reparation and Doping Strategy (Laser Photonics Rev. 15(12)/2021)

Monolayer Photoluminescence In article number 2100104 by Weizhen Liu, Haiyang Xu, and co-workers, a novel organic superacid trifluoromethanesulfonic (TFMS) is explored to significantly improve the photoluminescence quantum yield of CVD-grown monolayer MoS2 and WS2 to 14.1% and 56.7%, respectively. Through in-depth study and analysis with scanning transmission electron microscopy and density functional theory calculation, luminescence enhancement mechanism is attributed to a synergistic effect of TFMS-assisted sulfur vacancy repairation and p-type doping.

Effectively enhanced photoluminescence of CePO4:Tb3+ nanorods combined with carbon dots

CePO4:Tb3+ nanorods were successfully obtained via a simple hydrothermal method and combined with carbon dots (CDs) to obtain CDs@CePO4:Tb3+ nanorods. Due to the combination of CDs, the emission intensity of CDs@CePO4:Tb3+ nanorods increases about 92 times, compared with that of CePO4:Tb3+ nanorods. The combination of CDs and CePO4:Tb3+ nanorods was confirmed by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and so on. The mechanism of luminescence enhancement may be attributed to some aspects: the formation of hexagonal phase results in the increase of crystal field symmetry, and the energy transfer among CDs, Ce3+ and Tb3+ ions, which causes the Tb3+ ions in CDs@CePO4:Tb3+ nanorods to obtain more excited energy and less non-radiative attenuation compared to CePO4: Tb3+ nanorods. The luminescence enhancement strategy through combination of CDs would provide a simple and effective approach for other rare earth ions doped luminescent materials.

A red phosphor of Ba3In2F12:Mn4+ with enhanced moisture stability for warm WLED application

Although fluoride phosphors have distinguishing feature in luminescence spectra such as narrow band red light emission and broad band blue light excitation, the instability of [MnF6]2- limits their commercial applications. In this regard, we use weak reducing agents such as citric acid (CA) and oxalic acid (OA) for surface modification of a novel red phosphor Ba3In2F12:Mn4+ (BIF:Mn). A protective homogeneous passivation layer is formed on the surface of the phosphor particles with reduced Mn4+ content to improve the moisture resistance of Mn4+ doped fluoride phosphor BIF:Mn. In addition, their crystal structures, morphologies, photoluminescence characteristics, and the mechanism of luminescence enhancement are also described in details. By using near-ultraviolet or blue light-emitting diodes (LEDs) to excite it, an efficient red emission has been achieved with a maximum peak at 631 nm. In order to verify their application value, a warm white LED (WLED) with a color rendering index (CRI = 81.4) and a correlated color temperature (CCT = 4779 K) has fabricated with the as-prepared BIF:Mn and commercial yellow phosphor (YAG:Ce) on blue GaInN chip.

Luminescence Enhancement of Mn4+-Activated Fluorides via a Heterovalent Co-Doping Strategy for Monochromatic Multiplexing.

Mn4+ non-equivalent doped fluorides with high color purity red emission and relatively short decay time are crucial for wide color gamut displays and emerging applications, whereas the low quantum efficiency (QE) restrains their further applications. Herein, the luminescence of Mn4+ non-equivalent doped fluoride K2NaAlF6:Mn4+ (KNAF:Mn4+) is significantly enhanced via a heterovalent co-doping strategy, where the luminescence intensity is obviously increased by ∼85%, but the decay time is almost unchanged. The experimental characterization and density functional theory (DFT) calculations provide an understanding of the luminescence enhancement mechanism of heterovalent co-doping, which is enabled by simultaneously improving the stability of Mn4+ and reducing the number of quenching centers (defects and impurities). Combining the short-decay-time (τ = 4.03 ms) emission KNAF:Mn4+, Mg2+ and long-decay-time (τ = 9.23 ms) emission K2SiF6:Mn4+, a novel monochromatic multiplexing mode in the millisecond order is presented, which can be decoded not only in high-efficiency by a digital camera but also with a high security. This work provides a new optical multiplexing for the information security applications and also inspires the design of high-efficiency Mn4+-activated luminescent materials.

A novel Mn4+-activated Li3CsGe8O18 red phosphor and cation substitution induced photoluminescence improvement

Nowadays, non-rare-earth Mn4+-activated red phosphors have emerged for improvement of the lighting quality of phosphor-converted white light-emitting-diodes (pc-WLED), owing to the low cost and the admirable luminescence properties. In this work, a novel narrow-band red-emitting Li3CsGe8O18:Mn4+ phosphor was synthetized based on the component substitution from Li3RbGe8O18, which exhibits the red luminescence centered at 668 nm upon 466 nm excitation. By further designing [Cs+-Rb+] cation substitution, the photoluminescence intensity and luminescence efficiency are obviously improved. The photoluminescence intensity enhanced 1.75 times than Li3RbGe8O18:Mn4+ phosphor, while the corresponding internal quantum efficiency (IQE) increased by 1.57 times. According to the Rietveld refinement results, the corresponding mechanism of luminescence enhancement is attributed to the smaller distortion degree of the [Ge(1)O6] octahedron. The pc-WLED device is fabricated by the optimal Li3Cs0.5Rb0.5Ge8O18:1%Mn4+ red phosphor, yellow phosphor with Y3Al5O12:Ce3+ and 460 nm InGaN chip, showing a warm white light emission with low correlated color temperature (4474K) and high color rendering index (90.8). The result implies that the Li3Cs0.5Rb0.5Ge8O18:1%Mn4+ phosphor can be used as a potential red phosphor for pc-WLED application.

Ultrafast Luminescent Light-Up Guest Detection Based on the Lock of the Host Molecular Vibration.

Light-up luminescence sensors have been employed in real-time in situ visual detection of target molecules including volatile organic compounds (VOCs). However, currently employed light-up sensors, which are generally based on the aggregation-induced emission (AIE) or solvent-induced energy transfer effect, exhibit limited sensitivity for light-up detection and poor recycling performances thereby significantly hindering their industrial applications. Inspired by the low-temperature enhanced luminescence phenomenon, we herein propose and show that a guest-lock-induced luminescence enhancement mechanism can be used to realize the ultrafast light-up detection of target VOCs. Through introduction of chlorinated hydrocarbons to lock the molecular vibrations within a designed [Cu4I4]-based metal-organic framework (MOF), luminescence intensity could be enhanced significantly at room temperature. This guest-lock-induced luminescence enhancement is brought about by weak supramolecular interactions between the host framework and the guest molecules, allowing highly sensitive and specific detection of the guest vapor with ultrafast response time (<1 s). Single-crystal X-ray diffraction (SCXRD) analysis of guest molecules-loaded MOFs and density functional theory (DFT) calculations were employed to investigate the host-guest interactions involved in this phenomenon. Moreover, the above MOF sensor successfully achieved real-time detection of a toxic chloroaromatic molecule, chlorobenzene. The guest-lock-induced light-up mechanism opens up a route to discovering high-performance ultrafast light-up luminescent sensors for real-time detection applications.

Ionic Self-Assembled Luminescent Nanospheres from Cationic Polyelectrolyte and Eu-Containing Polyoxometalate.

Using the ionic self-assembly (ISA) strategy to combine Eu-containing polyoxometalates (Eu-POMs) and organic molecules mainly through noncovalent electrostatic interactions can protect Eu-POMs from solvent quenching of luminescence and enhance their processability. For this reason, a cationic polyelectrolyte, branched polyethyleneimine (PEI), and a Eu-POM, Na9(EuW10O36)·32H2O (EuW10), were used here to construct luminescence-enhanced spherical aggregates with diameters ranging from 50 to 200 nm. At a fixed concentration of EuW10, the phase behavior and luminescence properties of the mixture could be modulated by the PEI concentration. Such ISA-induced aggregates could effectively shield water molecules and result in better photophysical properties. Compared to bare EuW10, the absolute quantum yield and lifetime of luminescence for aggregates increased 10 and 5 times, respectively. Meanwhile, the sensitivity of the EuW10 coordination structure to the environment made it possible for obtained aggregates being used to detect either copper cations or permanganate anions due to their strong specific quenching effects to luminescence. Such a new type of luminescent soft material not only provided a reference for exploring the luminescence enhancement mechanism of lanthanide through self-assembly in aqueous solution but also exhibited potential in detection by luminescence analysis.

Plasma effect：A simple method for improving the persistent luminescence and light response range of persistent luminescent materials

The persistent luminescent materials are important energy-saving and environmentally friendly materials used in wide application range, but the application scale is relatively small. In order to overcome the problems of narrow light response range and low persistent luminescence performance, the Ag/Sr2MgSi2O7:Eu2+,Dy3+ structure was firstly shaped by a photoreduction deposition method. The persistent luminescence performance and the photo response range are greatly improved via the plasmon resonance after the deposition of Ag on the surface of Sr2MgSi2O7:Eu2+,Dy3+. The initial brightness can be increased by a factor of 9, while the range and intensity of absorbed light are greatly changed, indicating that the plasmon resonance of Ag can be applied to persistent luminescent material, which can efficiently increase the number of photogenerated electrons and holes which will be captured and released, thereby effectively improving the afterglow performance. The influence mechanism of Ag on the generation of photogenerated electrons and holes, the number and depth of traps, and the transfer-capture-release-luminescence mechanism of photogenerated electrons and holes, namely the persistent luminescence enhancement mechanism, are revealed. The development of this research can promote the application of Sr2MgSi2O7:Eu2+,Dy3+, and meanwhile provide an effective method for improving the persistent luminescence of various persistent luminescent materials.

Strategy to enhance the red-emission of CaWO4:Eu3+ phosphors assisted by poly acrylic acid (PAA)

Eu3+ activated CaWO4 (CWO) phosphors were prepared via a modified hydrothermal process. In present work, the phosphors illustrated enhanced emission properties by the assistance of poly acrylic acid (PAA). The phase structure, micromorphology, photoluminescence properties and luminescence enhancement mechanism of the as-prepared samples were investigated. The as-prepared PAA assisted samples exhibited significantly enhanced red emission peaking at 595 nm and emission intensity increased by about 8 times. The results indicated that CWO: Eu3+ samples could be a potential candidate of red phosphor for white light-emitting diodes (WLEDs).

Effect of chloride on spectrum properties of Pr3+/Ho3+ co-doped fluorozirconate glasses

An effective method of improving the luminescent properties of rare earth ions in fluoride glasses were reported. The Pr3+/Ho3+ co-doped fluorochlorozirconate luminescent glasses were prepared, and the effects of chloride on the spectral properties and structure of the glasses were studied. According to the results, the glass stability is improved, and the luminescence intensity in the visible range is significantly enhanced with the introduction of chloride. By introducing 7.5 mol% BaCl2, the luminescence intensity reaches the maximum and increases by three times. The mechanism of luminescence enhancement is explained by analyzing the correlation between the composition and the structure. The chloride ions disperse outside the glass network before the introduction of 7.5 mol% BaCl2 and increased dispersity of Pr3+ and Ho3+ ions in the fluorozirconate glasses.