Efficient red and broadband near-infrared luminescence in Mn2+/Yb3+-doped phosphate phosphor

In this work, we report a novel phosphor LSPO:Mn²⁺ that exhibits red emission at about 616 nm and pleasant broad near-infrared (NIR) emission at about 800 nm with a full width at half maximum (fwhm) of 112 nm. The structure and spectra show that the doped manganese ions occupy two kinds of Sc sites forming Mn1 and Mn2 emission centers, which are responsible for red and NIR emission, respectively. The XPS and low-temperature fluorescence spectra reveal that both red and NIR emissions come from the Mn²⁺ ions. Besides, NIR luminescence is improved by doping Yb³⁺ in LSPO:Mn²⁺, leading to the broadened NIR emission range (700-1100 nm) and enhanced luminescent thermal stability. Our results suggest that the prepared LSPO:Mn²⁺ and LSPO:Mn²⁺,Yb³⁺ phosphors offer the potential applications as red and NIR components in phosphor-converted white-light-emitting diodes (pc-WLED) and broadband NIR pc-LED. Meanwhile, this work provides a new way to design novel broadband NIR phosphors.     

Investigation of luminescence properties of Pb2+‐doped Sr2B2O5 phosphor

A near‐UV emitting phosphor, Pb²⁺‐doped Sr₂B₂O₅ was synthesized by the solid‐state reaction method at 900°C for 3 hours in air. The structure of the phosphor was verified by X‐ray diffraction study which shows monoclinic phase. Fourier transform infrared (FTIR) analysis confirmed the formation of Sr₂B₂O₅. The excitation and emission spectra of the synthesized phosphors were investigated at room temperature with photoluminescence spectrophotometer. The emission and excitation bands of Pb²⁺‐doped Sr₂B₂O₅ were observed at 370 and 289 nm, respectively. The dependence of the PL intensities on the Pb²⁺ concentration for the Sr_2?xPb_xB₂O₅ (0.01 ≤ x ≤ 0.03) phosphors was studied and it was observed that the concentration quenching of Pb²⁺ in Sr₂B₂O₅ is 0.025 mol.     

Concentration effects on the upconversion luminescence in Ho3+/Yb3+ co-doped NaGdTiO4 phosphor

Ho³⁺/Yb³⁺ co-doped NaGdTiO₄ phosphors were synthesized by a solid-state reaction method. The upconversion (UC) luminescence characteristics excited by 980 nm laser diode were systematically investigated. Bright green UC emission centered at 551 nm accompanied with weak red and near infrared (NIR) UC emissions centered at 652 and 761 nm were observed. The dependence of UC emission intensity on excitation power density showed that all of green, red and NIR UC emissions are involved in two-photon process. The UC emission mechanisms were discussed in detail. Concentration dependence studies indicated that Ho³⁺ and Yb³⁺ concentrations had significant influences on UC luminescence intensity and the intensity ratio of the red UC emission to that of the green one. Rate equations were established based on the possible UC mechanisms and a theoretical formula was proposed to describe the concentration dependent UC emission. The UC luminescence properties of the presented material was evaluated by comparing with commercial NaYF₄:Er³⁺, Yb³⁺ phosphor, and our sample showed a high luminescence efficiency and good color performance, implying potential applications in a variety of fields.     

Thermal effects of Er3+/Yb3+‐doped NaYF4 phosphor induced by 980/1510 nm laser diode irradiation

The thermal effects of Er/Yb‐doped NaYF₄ phosphor induced by 980/1510 nm laser diode irradiation were intuitively and contrastively investigated using an infrared thermal imaging technology with real‐time online monitoring. The Yb³⁺/Er³⁺ codoped materials have strong thermal effects and high‐temperature elevation under 980 nm irradiation. However, the severe thermal effects of materials with higher Er³⁺ ion doping concentration are remarkably attributed to the cross relaxation between the Er³⁺ ions under 980 nm irradiation. The energy transfer between Er³⁺ and Yb³⁺ ions in Er³⁺/Yb³⁺‐codoped materials also contributes to the thermal effects under 1510 nm laser diode irradiation. Under the same testing conditions, the temperature elevation ?T of samples induced by 1510 nm laser diode irradiation is lower than that induced by 980 nm laser diode irradiation. The temperature rising rate and elevation ?T value of samples depend on the ion doping concentration and power density of the laser diode excitation. The internal temperature of the samples exhibits deep temperature gradient under 980/1510 nm laser diode irradiation. By comparing the two kinds of thermometry methods, the temperature value calculated by fluorescence intensity ratio is almost similar to that obtained through infrared thermal imaging technology under higher excitation power pumping.     

Tunable multicolor upconversion luminescence of Yb3+ sensitized Na3La(VO4)2 crystals

Multicolor upconversion luminescence materials show significantly applications in materials science. In this paper, the novel Yb³⁺-sensitized Na₃La(VO₄)₂ upconversion luminescence crystals are synthesized by the solid-state reaction method. Three primary colors upconversion luminescence are successfully achieved in Na₃La(VO₄)₂:Yb³⁺,Tm³⁺, Na₃La(VO₄)₂:Yb³⁺,Er³⁺, and Na₃La(VO₄)₂:Yb³⁺,Ho³⁺ crystals excited by the single 980 nm LD. Multicolor upconversion luminescence can be obtained by simply adjusting the combination ratios of these three samples. Luminescence mechanisms of the Yb³⁺-sensitized system are discussed in detail. In the Na₃La(VO₄)₂ host material, the Yb³⁺/Ho³⁺ codoped system exhibits unusual red upconversion luminescence based on the short decay time of Ho³⁺ ion ⁵I₆ level, which provides the possibility of three primary color luminescence under 980 nm excitation.     

Luminescence behavior of Nd3+/Zr4+/3+ Co-activated ZrP2O7 persistent phosphor

The bluish-green long persistent phosphor (LPP) materials ZrP₂O₇:Nd³⁺ were synthesized in a reducing atmosphere by a conventional high-temperature solid state reaction. The XRD patterns, XPS survey scan, excitation and emission spectra, decay curves and thermoluminescence (TL) curves were used for investigating the structure and luminescence properties and mechanism of the materials. The emission band between 400 and 600 nm exhibit the characteristics of blue emission from d-d transitions of Zr and the characteristics of green emission from f-f transitions of Nd³⁺. The TL curves showed that the formation of high-concentration trap level at 337 K (0.73 eV) was mainly responsible for the LPP phenomenon of ZrP₂O₇:Nd³⁺ at room temperature.     

Optical temperature sensor based on upconversion luminescence of Er3+ doped GdTaO4 phosphors

For the development of optical temperature sensor, a series of GdTaO₄ phosphors with various Er³⁺-doping concentrations (0, 1, 5, 10, 25, 35, 50 mol%) were synthesized by a solid-state reaction method. The monoclinic crystalline structure of the prepared samples was determined by X-ray diffraction (XRD). Under excitations of 980 and 1550 nm lasers, the multi-photon-excited green and red upconversion (UC) luminescence emissions of Er³⁺ were studied, and the critical quenching concentration of Er³⁺-doped GdTaO₄ phosphor was derived to be 25 mol%. By changing the pump power of laser, it was found that the two-photon and three-photon population processes happened for the UC emissions of Er³⁺-doped GdTaO₄ phosphors excited by 980 and 1550 nm lasers, respectively. Furthermore, based on the change of thermo-responsive green UC luminescence intensity corresponding to the ²H_11/2 → ⁴I_15/2 and ⁴S_3/2 → ⁴I_15/2 transitions of Er³⁺ with temperature, the optical temperature sensing properties of Er³⁺-doped GdTaO₄ phosphor were investigated under excitations of 980 and 1550 nm lasers by using the fluorescence intensity ratio (FIR) technique. It was obtained that the maximum absolute sensitivity (S_A) and relative sensitivity (S_R) of Er³⁺-doped GdTaO₄ phosphors are as high as 0.0041 K⁻¹ at 475 K and 0.0112 K⁻¹ at 293 K, respectively. These significant results suggest that the Er³⁺-doped GdTaO₄ phosphors are a promising candidate for optical temperature sensor.     

La2O2SO4:RE/Yb new phosphors for near infrared to visible and near infrared upconversion luminescence (RE=Ho,Er, Tm)

The 3 new upconversion (UC) phosphors of La₂O₂SO₄:RE/Yb (RE=Ho, Er, and Tm, respectively) were derived via facile dehydration of their layered hydroxide precursors that were hydrothermally synthesized at 100°C. Rietveld XRD refinement found contracting cell dimension with decreasing RE³⁺ size, confirming the direct crystallization of solid solution. The Er³⁺ and Ho³⁺ activators both exhibited simultaneous green and red (dominant) emissions under 978‐nm near‐infrared (NIR) laser excitation (NIR‐Vis UC). Particularly, Tm³⁺ produced a Gaussian‐shaped pure NIR emission band at ~812 nm via its ³H₄ → ³H₆ transition (NIR‐NIR UC), which is highly desired for NIR biological application. Analysis of the excitation‐power dependent UC properties manifested a 3‐photon mechanism for the 3 phosphors, and the possible photon reactions leading to UC were illustrated.     

Tunable upconversion luminescence in new Ho3+/Yb3+-doped SrBi4Ti4O15 photochromic ceramics for switching application

Upconversion (UC) luminescence modulation is quite important in controlling and processing light for active components of light sources, photoswitches, optical memories, and optical sensing devices. In this work, we reported one kind of novel phosphor, Ho³⁺/Yb³⁺-doped SrBi₄Ti₄O₁₅ ceramics, which displayed both strong UC luminescence and obvious photochromic (PC) reaction. The UC luminescence, PC effect, and the modulation of UC performance based on PC behavior were investigated in detail. By alternating visible light irradiation and thermal stimulus, the UC luminescence could be reversibly regulated. Meanwhile, the modulation was unveiled to tightly rely on the irradiation time and thermal treatment processes. Excellent reproducibility was also achieved. In addition, as an alternative method to thermal treatment, the manipulation of luminescence by electric field was also explored. Finally, the mechanism related to the UC luminescence manipulation was illustrated. The results indicate that these samples could be potentially utilized in optical data storage and anti-counterfeiting security fields.     

Preparation and infrared to visible upconversion luminescence of Yb2O3:Ho3+ nanocrystalline powders

Yb₂O₃:Ho³⁺ nanocrystalline powders were synthesized through a solid state reaction method. X-ray diffraction analysis and field emission scanning electron microscopy were used to analyze the phase composition and morphology of the powders. Then under the 980 nm excitation of laser diode, the fluorescence of the crystals was studied via a fluorescence spectrometer. The green and red emissions centered on 551 and 668 nm were observed, and the green band dominated the emission spectrum. The effect of the concentration of Ho³⁺ on the upconversion luminescence intensity was discussed and the possible upconversion emission mechanism was explained. It indicates that like other metal oxide nanoparticles, Yb₂O₃ could also be a potential host material for doping to prepare the upconversion phosphor.     

MgAl2O4:Ce荧光粉辐照合成及发光机理研究

通过伽马射线辐照辅助聚丙烯酰胺凝胶法合成了MgAl₂O₄和MgAl₂O₄:Ce荧光粉。通过X射线粉末衍射仪（XRD）、透射电子显微镜（TEM）、紫外可见分光光度计和荧光分光光度计研究了MgAl₂O₄:Ce荧光粉的晶体结构、表面形貌、光学性质和发光性质;基于实验所获得的结果,分析了纳米级MgAl₂O₄:Ce荧光粉的发光机理。实验结果表明:采用伽马射线辐照辅助聚丙烯酰胺凝胶法制备纯相MgAl₂O₄和MgAl₂O₄:Ce荧光粉的结晶温度要比传统聚丙烯酰胺凝胶法低100 ℃左右;MgAl₂O₄:Ce荧光粉的平均颗粒尺寸为14 nm,Ce离子掺杂后导致样品颗粒细化;Ce离子的掺入,降低了MgAl₂O₄的能带值,改善了其颜色性质和发光性质;当采用275 nm的光去激发MgAl₂O₄:Ce荧光粉时,获得了425 nm和464 nm的蓝光发射。通过能量传递原理分析认为,杂质缺陷（Ce³⁺）在整个发光过程中扮演了重要角色。MgAl₂O₄:Ce作为一种抗辐射能力强的荧光粉,在空间照明领域具有很好的应用前景。     

Phase evolution,structure, and up-/down-conversion luminescence of Li6CaLa2Nb2O12:Yb3+/RE3+ phosphors (RE = Ho,Er, Tm)

Garnet-type Li₆Ca(La_0.97Yb_0.02RE_0.01)₂Nb₂O₁₂ (RE = Ho, Er, Tm) new phosphors were successfully synthesized via solid reaction at 900°C for 5 hours, whose course of phase evolution, macroscopic/local crystal structure and up-/down-conversion (UC/DC) photoluminescence were clarified. Mechanistic study and materials characterization were attained via XRD, Rietveld refinement, DTA/TG, electron microscopy (FE-SEM/TEM), and Raman/reflectance/fluorescence spectroscopies. The phosphors were shown to exhibit UC luminescence dominated by a ~ 553 nm green band (⁵F₄/⁵S₂ → ⁵I₈ transition) for Ho³⁺, a ~ 568 nm green band (⁴S_3/2 → ⁴I_15/2 transition) for Er³⁺ and a ~ 806 nm near-infrared band (³H₄ → ³H₆ transition) for Tm³⁺ under 978 nm laser excitation, with CIE chromaticity coordinates of around (0.31, 0.68), (0.38, 0.60) and (0.17, 0.24), respectively. Analysis of the pump-power dependence of UC intensity indicated that all the emissions involve a two-photon mechanism except for the ~ 486 nm blue emission of Tm³⁺ (¹G₄ → ³H₆), which requires a three-photon process. The DC luminescence of these phosphors is featured by dominant bands at ~ 553 nm for Ho³⁺ (green, ⁵F₄/⁵S₂ → ⁵I₈ transition), ~568 nm for Er³⁺ (green, ⁴S_3/2 → ⁴I_15/2 transition) and ~ 464 nm for Tm³⁺ (blue, ¹D₂ → ³F₄ transition). The UC and DC properties were also comparatively discussed.     

Mn4+-related photoemission enhancement via energy transfer in La2MgGeO6:Dy3+, Mn4+ phosphor for plant growth light-emitting diodes

A double perovskite-type substrate of La₂MgGeO₆ (LMGO) was successfully synthesized via a high-temperature solid-state reaction method and was codoped with Mn⁴⁺ and Dy³⁺ to form a new deep-red phosphor (LMGO:Mn⁴⁺,Dy³⁺) for artificial plant growth light-emitting diodes (LEDs). This extraordinary phosphor can exhibit strong far-red emission with a maximum peak at 708 nm between 650 and 750 nm, which can be ascribed to the ²E_g → ²A_2 g spin-forbidden transition of Mn⁴⁺. The X-ray diffraction (XRD) patterns and high-resolution transmission electron microscopy (HRTEM) clarified that the La³⁺ sites in the host were partly replaced by Dy³⁺ ions. Moreover, we discovered energy transfers from Dy³⁺ to Mn⁴⁺ by directly observing the significant overlap of the excitation spectrum of Mn⁴⁺ and the emission spectrum of Dy³⁺ as well as the systematic relative decline and growth of the emission bands of Dy³⁺ and Mn⁴⁺, respectively. With the increase in the activator (Mn⁴⁺) concentration, the relationship between the luminescence decay time and the energy transfer efficiency of the sensitizer (Dy³⁺) was studied in detail. Finally, an LED device was fabricated using a 460 nm blue chip, and the as-obtained far-red emitting LMGO:Mn⁴⁺,Dy³⁺ phosphors for Wedelia chinensis cultivation. As expected, the as-fabricated plant growth LED-treated Wedelia chinensis cultured in the artificial climate box with overhead LEDs demonstrated that after 28 days of irradiation, the average plant growth rate and the total chlorophyll content were better than those of specimens cultured using the commercial R-B LED lamps, indicating that the as-prepared phosphor could have a potential application in the agricultural industry.     

Near white light emission of Ce3+‐, Ho3+‐, and Sm3+‐doped oxyfluoride silicate glasses

The Ce³⁺‐, Ho³⁺‐, and Sm³⁺‐ single and co‐doped oxyfluoride silicate glasses for light emitting diodes are studied. These glasses were prepared by melt quenching method and their optical and structural properties were investigated by absorption spectra, photoluminescence spectra, Commission International de I'Eclairage chromaticity coordinates, X‐ray diffraction, and Fourier transform infrared spectra. It is found that the introduction of Al₂O₃ in glass composition can improve the emissions of Ho³⁺ and Sm³⁺. While the presence of B₂O₃ has the adverse effect and can suppress the emissions of Ho³⁺ and Sm³⁺. With substituting Na₂O for CaO in the glass compositions, CaF₂ crystals can be formed during the melt quenching process. We find the formation of CaF₂ crystals can change the emission behavior of Ho³⁺ and Sm³⁺ ions. White light emissions can be achieved in the glasses and the luminescence colors can be tuned by varying the concentrations of the doped rare‐earth ions and the composition of glass matrix. The Ce³⁺‐, Ho³⁺‐, and Sm³⁺‐doped oxyfluoride silicate glasses presented here demonstrate promising applications in the fields of light emitting diodes.     

Facile precipitation synthesis of green-emitting BaY2F8:Yb3+, Ho3+ upconverting phosphor

Monoclinic phase of BaY₂F₈:0.2Yb³⁺, xHo³⁺ (x = 0.005, 0.01, 0.02, 0.05 and 0.1 mol) and BaY₂F₈:yYb³⁺, 0.02Ho³⁺ (y = 0.01, 0.02, 0.05, 0.1 and 0.2 mol) phosphors were prepared by a facile precipitation method. Rietveld analysis was employed to carry out the structural refinement. The upconversion (UC) luminescence properties of BaY₂F₈:Yb³⁺, Ho³⁺ phosphor were investigated under near infra-red (NIR) excitation and the influence of dopant concentration on their spectra was also accessed. The possible UC processes and the energy transfer mechanisms between Yb³⁺ and Ho³⁺ were discussed on the basis of UC decay curves and the UC spectra obtained from a laser-pump power variation. The thermal stability of the BaY₂F₈:0.2Yb³⁺, 0.02Ho³⁺ phosphor was studied in the range of 30–300 °C. The color coordinates of the phosphor were located in the green region with very high color purity.     

Preparation of MGF phosphor by O2 postannealing and impact on luminescence properties and crystal lattice

Mn⁴⁺-activated phosphors, Mg₂₈Ge₁₀O_48-δF_δ:Mn⁴⁺ (MGFs), can be obtained through an oxygen postannealing process. Analyses of the crystal structure and elemental composition by powder X-ray diffraction (XRD) and electron probe microanalysis (EPMA), respectively, indicated that under an O₂ atmosphere, oxygen atoms were substituted with fluorine atoms in the original MGF structure to leach the fluorine atoms with germanium atoms as GeF₄ by oxygen postannealing. The MGF phosphor annealed in O₂ exhibited ~1.3 times higher quantum efficiency (QE) than that annealed in ambient air. The Raman spectroscopy results suggested that an increase in the content of the [Mn⁴⁺O₆] octahedron led to an increase in the QE values. Additionally, the relaxation of lattice defects in the lattice interior and on the surface observed by XRD and X-ray photoelectron spectroscopy (XPS) measurements could explain the change in thermal quenching behavior between the different atmospheres, and the decrease in lattice defects increased the QE. The investigation of MGF phosphors prepared by different processes provides insight into the relationships among the surface and local structures, chemical composition, and photoluminescence properties. The optimized synthetic procedure increases the Mn⁴⁺ content and decreases the Mn²⁺ and Mn³⁺ contents in the phosphor, which drastically increases the luminescence efficiency.     

Spectral management and energy‐transfer mechanism of Eu3+‐doped β‐NaGdF4:Yb3+,Er3+ microcrystals

β‐NaGdF₄:Yb³⁺,Er³⁺ upconversion (UC) microcrystals were prepared by a facile hydrothermal process with the assistance of ethylene diamine tertraacetic acid (EDTA). The β‐NaGdF₄ UC microcrystal morphology was controlled by changing the doses of EDTA and NaF. Uniform hexagonal structure can be obtained at the 2 mmol EDTA and 9‐10 mmol NaF. The UC emissions of β‐NaGdF₄:Yb³⁺,Er³⁺ microcrystals were tuned by the variation of Eu³⁺ doping level (0%‐5%), where the red/green intensity ratio decreased with the Eu³⁺ concentration increase. It was found on the base of rate equations that with the Eu³⁺ doping, the energy back transfer process ²H_11/2/⁴S_3/2 (Er³⁺) → ⁴I_13/2 (Er³⁺) decreased. In addition, an energy‐transfer process from ⁴F_7/2 (Er³⁺) to ⁵D₁ (Eu³⁺) and a cross relaxation process of ⁷H_9/2 (Er³⁺) + ⁵D₀ (Eu³⁺) → ⁴F_7/2 (Er³⁺) + ⁵D₂ (Eu³⁺) were proposed and verified by rate equations, which dominated the energy‐transfer mechanism between Er³⁺ and Eu³⁺, resulted in the spectra tuning of β‐NaGdF₄:Yb³⁺,Er³⁺. The results suggested that the color tuning of β‐NaGdF₄:Yb³⁺,Er³⁺,Eu³⁺ UC microcrystals would have potential applications in such fields as flat‐panel displays, solid‐state lasers, and photovoltaics.     

Effect of crystalline fraction on upconversion luminescence in Er3+/Yb3+ Co-doped NaYF4 oxyfluoride glass-ceramics

The crystalline fraction were adjusted MgO concentration and the corresponding effect on upconversion (UC) luminescence in Er³⁺/Yb³⁺ co-doped NaYF₄ oxyfluorode glass-ceramics was investigated. With increase of MgO and the content of Na₂O reduced, the internal network structure of the glass became compact, which made the size of NaYF₄ nanocrystals unchanged, while the average distance between the nanocrystals increased significantly. Crystal growth is limited with the glass network, keeping the crystal size not changed. SNM-1 glass ceramics samples show a predominant red up-conversion emission under near infrared excitation at 980 nm, while a predominant green emission is observed in the SNM-3 samples. In this paper, it was indicated that it changed the effect of glass network modifier MgO in the glass structure. The possible mechanism responsible for the color variation of UC in Er³⁺/Yb³⁺ co-doped was discussed.     

Synthesis and luminescence properties of single‐component Ca5(PO4)3F:Dy3+, Eu3+ white‐emitting phosphors

A series of Ca₅(PO₄)₃F:Dy³⁺, Eu³⁺ phosphors was synthesized by a solid‐state reaction method. The XRD results show that all as‐prepared Ca₅(PO₄)₃F:Dy³⁺, Eu³⁺ samples match well with the standard Ca₅(PO₄)₃F structure and the doped Dy³⁺ and Eu³⁺ ions have no effect on the crystal structure. Under near‐ultraviolet excitation, Dy³⁺ doped Ca₅(PO₄)₃F phosphor shows blue (486 nm) and yellow (579 nm) emissions, which correspond to ⁴F_9/2→⁶H_15/2 and ⁴F_9/2→⁶H_13/2 transitions respectively. Eu³⁺ co‐doped Ca₅(PO₄)₃F:Dy³⁺ phosphor shows the additional red emission of Eu³⁺ at 631 nm, and an improved color rendering index. The chromaticity coordinates of Ca₅(PO₄)₃F:Dy³⁺, Eu³⁺ phosphors also indicate the excellent warm white emission characteristics and low correlated color temperature. Overall, these results suggest that the Ca₅(PO₄)₃F:Dy³⁺, Eu³⁺ phosphors have potential applications in warm white light‐emitting diodes as single‐component phosphor.     

Toward temperature-dependent Bi3+-related tunable emission in the YVO4:Bi3+ phosphor

Up until now, many previous works have indicated us that the photoluminescence (PL) properties of phosphors sometimes can be changed with the change in the external temperature, resulting in the anomalous PL phenomena and correlated new applications that are difficult to achieve at room temperature. In this work, we report the temperature-dependent Bi³⁺-related PL properties in the YVO₄:Bi³⁺ phosphor. Our findings show that increasing the temperature from 10 to 300 K enables manipulating the energy interaction from groups to Bi³⁺, thereby leading to the temperature-induced color tuning from blue (0.183, 0.212) to yellow (0.418, 0.490). Upon this heating process, we further reveal that the dynamic Bi³⁺ luminescence has experienced a regular transition from double-exponential to single-exponential decay, which results in the decrease in the average Bi³⁺ lifetime from 122.606 to 0.376 μs. Discussions on the PL results imply that the tunable PL observations are due to the interplay of temperature-dependent energy transfer from groups to Bi³⁺ and redistribution of the excited ³P₀ and ³P₁ states of Bi³⁺ upon the thermal stimulation. This work not only presents the temperature-triggered Bi³⁺ tunable properties in the well-studied YVO₄ host lattice but also can provide new insights into revealing Bi³⁺-related PL mechanism in other Bi³⁺-doped photonic materials in the future and, in the meanwhile, gives some directive ideas for us to explore previously unnoticed applications for rare-earth (RE; eg, Eu³⁺, Pr³⁺, Tb³⁺, Eu²⁺, Er³⁺, etc) and other non-RE (eg, Bi³⁺, Mn⁴⁺, Mn²⁺, Cr³⁺, etc) doped phosphors.