Preparation and luminescent properties of color-adjustable La1-x-ySiBO5: xTb3+, yEu3+ phosphor for NUV-LEDs

Wenyu Zhao; Jiacheng Zhao; Lele Gao; Huihui Cao; Xuening Ding; Songbo Li

doi:10.1371/journal.pone.0344199

Abstract

A series of La_1-x-ySiBO₅:xTb³⁺, yEu³⁺ phosphors was synthesized through high-temperature solid-state reaction. The crystal structure, morphology, and luminescence properties of the phosphors were characterized by employing X-ray diffraction, scanning electron microscopy, photoluminescence, photoluminescence excitation and fluorescence lifetime measurements. Results show that the excitation spectra of La_1-xSiBO₅:xTb³⁺ and La_1-ySiBO₅:yEu³⁺ overlap at 300–400 nm, and the La_1-x-ySiBO₅:xTb³⁺, yEu³⁺ phosphors emit yellowish green (530–560 nm) and red (580–650 nm) light under 377 nm excitation. When x = 0.05 and y increases from 0.005 to 0.05, the emission intensity of Tb³⁺ decreases gradually, whereas that of Eu³⁺ increases gradually. This trend indicates energy transfer from Tb³⁺ to Eu³⁺ and color change from green to yellow and then red. The fluorescence lifetime test further confirms energy transfer from Tb³⁺ to Eu³⁺. The prepared LaSiBO₅:Tb³⁺, Eu³⁺ phosphors exhibit effective tunable emission and near ultraviolet excitation and thus have potential applications in White-LEDs.

Citation: Zhao W, Zhao J, Gao L, Cao H, Ding X, Li S (2026) Preparation and luminescent properties of color-adjustable La_1-x-ySiBO₅: xTb³⁺, yEu³⁺ phosphor for NUV-LEDs. PLoS One 21(3): e0344199. https://doi.org/10.1371/journal.pone.0344199

Editor: Mallikarjuna Reddy Kesama, Purdue University, UNITED STATES OF AMERICA

Received: October 11, 2025; Accepted: February 17, 2026; Published: March 13, 2026

Copyright: © 2026 Zhao et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data are within the manuscript and its Supporting Information files.

Funding: This work was supported by Natural Science Foundation of Inner Mongolia Autonomous Region 2024LHMS02003 and Open Project of Rare Earth Advanced Materials Technology Innovation Center G2025-K-07(14)-29(51). Natural Science Foundation of Inner Mongolia Autonomous Region 2024LHMS02003 had a role in study design, data collection and analysis. Open Project of Rare Earth Advanced Materials Technology Innovation Center G2025-K-07(14)-29(51) had a role in decision to publish and preparation of the manuscript.

Competing interests: We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of the manuscript entitled ” Preparation and luminous properties of color-adjustable La_1-x-ySiBO₅: xTb³⁺, yEu³⁺ phosphor for NUV-LEDs ”.

1. Introduction

Phosphor-converted white light emitting diodes (PC-WLEDs), which are composed of phosphors and blue/NUV semiconductor chips, have considerable applications in solid-state lighting because of their excellent color stability and luminescence performance [1,2]. As an important component of PC-WLED devices, phosphors have a remarkable influence on device application performance, such as color rendering index (CRI), correlation color temperature (CCT), luminescence efficiency, and thermal stability. Among factors, the choice of phosphors is the most important for good CRI and stability, especially for full-spectrum LEDs that are similar to the solar spectrum with high CRI and considered as healthy lighting for human beings. Blue, green, and red phosphors pumped by near-ultraviolet chips can achieve full-spectrum LEDs with higher CRI and lower CCT compared with conventional WLEDs composed of blue chips and yellow YAG:Ce³⁺ phosphors. Given that phosphors of different matrices have different degrees of thermal stability and water resistance, a color shift occurs during phosphor service. Hence, doping the same phosphor matrix with different luminous centers produces a wide band of colors and similar reliability over time. Research has proven that Tb³⁺→Eu³⁺ energy transfer is effectively color tunable. Examples include Mg₂SiO₄:Tb³⁺, Eu3+ [3], Ca₈ZnM (PO₄)₇ (M = Lu/Tb, Lu/Eu, and Tb/Eu) [4], and Sr₃Y(BO₃)₃:Tb³⁺, Eu3+ [5]. All reports have confirmed that energy transfer between Tb³⁺ and Eu³⁺ occurs through dipole–dipole interaction. For the choice of the phosphor matrix, borate-based host materials are excellent luminescent materials that have the advantages of a remarkably low synthesis temperature from borate and good chemical stability from silicate and exhibits potential for application in LED lamps and displays [6–9]. The specific LaSiBO₅ host matrix of phosphors has not been reported yet. In this study, Tb³⁺- and Eu³⁺-codoped LaSiBO₅ phosphors with adjustable color were prepared through traditional high-temperature solid-state reaction for the first time, and their luminous properties were studied in detail.

2. Materials and methods

2.1. Preparation

The raw materials SiO₂ (A.R.), H₃BO₃ (A.R.), La₂O₃ (99.99%), Tb₄O₇ (99.99%), and Eu₂O₃ (99.99%) were weighed in accordance with the stoichiometric ratios of the La_1-xSiBO₅:xTb³⁺(x = 0.03–0.15), La_1-ySiBO₅:yEu³⁺(y = 0.09–0.25), and La_1-x-ySiBO₅:0.05Tb³⁺, yEu³⁺ (y = 0.001, 0.005, 0.01, 0.02, 0.03, 0.05) phosphors. The ingredients were thoroughly ground in an agate mortar, then transferred into a crucible, and sintered at 1150 °C for 5 h in air atmosphere. After cooling to room temperature, the final product was obtained.

2.2. Characterization

X-ray diffraction (XRD, D8 ADVANCE, Bruck) was used to determine the crystal structures of the samples. The radiation source was the Cu target K_α (λ = 0.15406 nm), and the scanning 2θ range was 10°–80°. The surface morphology of the phosphors was analyzed through scanning electron microscopy (SEM, QUANTA 400, FEI). Photoluminescence–photoluminescence excitation was measured with a fluorescent spectrometer (Hitachi, F-4600) with a 150 W xenon lamp as the excitation source. Luminescence decay curves were recorded with a combined fluorescence lifetime and steady-state spectrometer (Edinburgh FLS920). All the above tests were conducted at room temperature.

3. Results and discussion

The XRD patterns of the La_0.95SiBO₅:0.05Tb³⁺, La_0.82SiBO₅:0.18Eu³⁺, and La_0.93SiBO₅:0.05Tb³⁺, 0.02Eu³⁺ samples are shown in Fig 1(a). LaSiBO₅ is trigonal, and its crystal structure parameters are a = 6.876 Å, b = 6.876 Å, c = 6.744 Å, and V = 281.05 Å³. All diffraction peaks of the samples are consistent with those in the JCPDS#19–0650 standard card, indicating that doping with Tb³⁺ and Eu³⁺ does not change the crystal structure of the matrix and does not produce any impurity phases. The XRD diﬀraction peaks of the samples slightly deviate to the higher angle, indicating that the interplanar crystal spacing d in the sample is smaller than that in the pure phase LaSiBO₅. In accordance with the radius and valence similarity principle, when La³⁺ is replaced by Tb³⁺ and Eu³⁺ in the matrix, the ionic radii of Eu³⁺ and Tb³⁺ become slightly smaller than that of La³⁺ (R_La = 106 pm, R_Eu = 95 pm, and R_Tb = 92 pm), resulting in a decrease in d value. It will lead to lattice distortion and diﬀraction peak splitting [10]. Fig 1(b) shows the magnified local image which can demonstrate the diffraction peak splitting clearly.

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Fig 1. XRD patterns.

(A) LaSiBO₅:Tb³⁺, Eu³⁺ phosphors and JCPDS card. (B) Magnified local image.

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In terms of the relationship between phosphor morphology and luminous performance, particle size homogeneity is evidently beneficial for facile coating and uniform color. However, ground particles that are too small destroy crystal structure and degrade luminous performance. The particle size of phosphor coatings on chips should be uniform and less than 20 μm. The SEM images of the La_0.93SiBO₅:0.05Tb³⁺, 0.02Eu³⁺ sample are shown in Fig 2. All the particles are spherical and uniform in size with slight agglomeration. The particle size is mostly distributed below 5 μm, which is applicable to LED packaging.

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Fig 2. Morphology of La_0.93SiBO₅:0.05Tb³⁺, 0.02Eu³⁺ sample.

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Fig 3(a) shows that when 369 nm NUV light is used as the excitation wavelength, the emission peaks are located at 415, 439, 490, 544, 588, and 623 nm, corresponding to the ⁵D₃→⁷F₅, ⁵D₃→⁷F₄, ⁵D₄→⁷F₆, ⁵D₄→⁷F₅, ⁵D₄→⁷F₄, and ⁵D₄→⁷F₃ energy level transitions of Tb³⁺, respectively [11,12]. Among these energy level transitions, ⁵D₄→⁷F₅ at 544 nm is the strongest. Under 544 nm monitoring, the excitation peaks are located at 303, 318, 341, 351, 369, and 377 nm, corresponding to the ground state ⁷F₆ and the excited states ⁵H₆, ⁵D₀, ⁵L₇, ⁵L₉, ⁵G₅, and ⁵G₆ of Tb³⁺ [13,14]. The strongest excitation peak is located at 369 nm. In general, the doping amount of rare earth ions is an important factor for the emission intensity of phosphors. The emission spectra of La_1-xSiBO₅:xTb³⁺ were collected under the same test conditions shown in Fig 3(b). The emission spectra show the same shape as the Tb³⁺ doping amount increases. However, the emission intensity gradually increases and reaches the maximum value when the Tb³⁺ concentration is 0.05. When the Tb³⁺ concentration exceeds 0.05, the luminescence intensity begins to decrease. This phenomenon, which is known as concentration quenching, is caused by the migration of excited energy between luminous ions or to quenching centers, leading to a loss of excited energy through nonradiative transitions [15]. The concentration quenching mechanism can be explained in accordance with the Blasse formula below [16]:

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Fig 3. Photoluminescence spectra of LaSiBO₅:Tb³⁺. (A) Excitation spectra. (B) Emission spectra of La_1-xSiBO₅:xTb³⁺ phosphors.

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(1)

where R_C is the critical distance, V represents the unit cell volume (281.05 Å³), N is the number of cations in the unit cell (6), and x_e is the optimal concentration of Tb³⁺ (0.05). The mechanism is exchange interaction when the critical distance is less than 5 Å and is multipolar interaction otherwise. Calculation shows that R_C = 12.14 Å, which is considerably larger than 5 Å. Therefore, the concentration quenching of La_1-xSiBO₅:xTb is mainly based on multipolar interaction. Three types of multipole interactions exist: dipole–dipole (d–d), dipole–quadrupole (d–q), and quadrupole–quadrupole (q–q). They can be calculated with the formula [17]:

(2)

where I is the luminous intensity; x represents the activator content, %; C is a constant; and θ is a multipolar interaction function. θ values of 6, 8, and 10 represent d–d, d–q, and q–q interactions, respectively. The emission intensity at 544 nm under 369 nm excitation was measured when 0.03 ≤ x ≤ 0.15. The linear relationship between lg (I/x) and lg (x) was linearly fitted by using Origin2021 software, and the slope of the straight line was obtained as −(θ/3) = −2.34563, that is, θ ≈ 6. As can be inferred from this result, the concentration quenching mechanism of La_1-xSiBO₅:xTb(0.03 ≤ x ≤ 0.15) is the d–d interaction.

Fig 4(a) shows no significant difference in the shape and position of excitation spectra among the phosphor samples with different doping concentrations. However, a considerable difference in intensity is observed. The excitation spectra of La_1-ySiBO₅:yEu³⁺ are composed of strong 4f–4f electron transition absorption (300–500 nm), and the main excitation peaks are located at 362, 376, 393, and 465 nm. The strongest excitation peaks at 393 nm correspond to the ⁷F₀–⁵L₆ energy level transition of Eu3+ [18]. Fig 4(b) shows that the main peaks of the emission spectrum are located at 580 and 589 nm, corresponding to the ⁵D₀–⁷F₀ characteristic transition and Eu³⁺ MD transition, respectively. The main peaks of the emission spectra are located at 598, 616, 654, and 703 nm and are attributable to the ⁵D₀–⁷F₁, ⁵D₀–⁷F₂, ⁵D₀–⁷F₃, and ⁵D₀–⁷F₄ characteristic transitions of Eu³⁺, respectively [19,20]. In accordance with the energy level distribution characteristics of Eu³⁺, ⁵D₀–⁷F₂ dominates the spectrum and belongs to the electric dipole transition. The strongest emission peak is located at 616 nm. The symmetry of Eu³⁺ in the lattice can be deduced from the emission characteristics of ⁵D₀→⁷F_J (J = 0, 1, 2, 3). When Eu³⁺ occupies inversely symmetric positions, its magnetic dipole transition ⁵D₀→⁷F₁ dominates and emits orange light. Conversely, if Eu³⁺ is located in a noninversely symmetric position, then the red emission of the electric dipole transition ⁵D₀→⁷F₂ is stronger than that of the magnetic dipole transition ⁵D₀→⁷F₁. The emission color is affected by the environment of the matrix crystal field and is related to the crystallographic position occupied by Eu3+ [21]. Given that the emission peak corresponding to the ⁵D₀→⁷F₂ transition has greater intensity than that corresponding to the ⁵D₀→⁷F₁ transition, the material mainly emits red light.

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Fig 4. Photoluminescence spectra of LaSiBO₅:Eu³⁺. (A) Excitation spectra. (B) Emission spectra of La_1-ySiBO₅:yEu³⁺ phosphors.

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Fig 5(a), (b), and (c) show the excitation and emission spectra of La_0.93SiBO₅:0.05Tb³⁺, 0.02Eu³⁺; the excitation and emission spectra of La_0.95-ySiBO₅:0.05Tb³⁺, yEu³⁺ samples; and the emission intensities at 490, 544, 589, and 616 nm of La_0.95-ySiBO₅:0.05Tb³⁺, yEu³⁺ samples. Fig 5(a) displays that at the excitation wavelength of 377 nm, the fluorescence spectra of La_0.93SiBO₅:0.05Tb³⁺, 0.02Eu³⁺ show the typical red emission of Eu³⁺ and the typical green emission of Tb³⁺. The emission spectrum of Tb³⁺ and the excitation spectrum of Eu³⁺ overlap at 400–425 nm, proving the possibility of energy transfer. The emission peaks at 491 and 544 nm observed under 377 nm excitation are attributed to the ⁵D₄→⁷F₆ and ⁵D₄→⁷F₅ energy level transitions of Tb³⁺, respectively. In addition, the emission peaks at 590 and 616 nm correspond to the characteristic transitions of ⁵D₁→⁷F₁ and ⁵D₀–⁷F₂ from Eu³⁺, respectively. The excitation spectrum of La_0.93SiBO₅:0.05Tb³⁺, 0.02Eu³⁺ was monitored at 616 nm, as shown in Fig 5(a). The excitation spectrum shows the typical excitation peaks of Tb³⁺ (377 nm) and Eu³⁺ (393 nm). However, when monitored at the typical Tb³⁺ emission of 544 nm, the excitation spectrum of La_0.93SiBO₅:0.05Tb³⁺, 0.02Eu³⁺ does not show the characteristic excitation peaks of Eu³⁺. Therefore, the energy transfer of LaSiBO₅:Tb³⁺, Eu³⁺ has occurred, and the energy transfer of Tb³⁺→Eu³⁺ is irreversible [22]. A series of La_0.95-ySiBO₅:0.05Tb³⁺, yEu³⁺ (y = 0, 0.001, 0.005, 0.01, 0.02, 0.03, 0.05) phosphors was prepared to determine the optimal concentration of Tb³⁺/Eu³⁺ codoping in the LaSiBO₅ matrix. The excitation and emission spectra of the Tb³⁺- and Eu³⁺-codoped samples are shown in Fig 5(b). All the spectra have similar shapes but not peak height. With the gradual increase in Eu³⁺ concentration, the intensity of the emission peaks at 590 and 616 nm gradually increases and that of the emission peaks at 491 and 544 nm gradually decreases. As shown in Fig 5(c), with the increase in the Eu³⁺ concentration in the La_0.95-ySiBO₅:0.05Tb³⁺, yEu³⁺ phosphor, the intensities of emission from Eu³⁺ at 589 and 616 nm increase and those from Tb³⁺ at 490 and 544 nm decrease. Therefore, the color of the L_a1-x-ySiBO₅:xTb³⁺, yEu³⁺ phosphors can be effectively regulated by controlling the doping concentration ratio of Eu³⁺:Tb³⁺.

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Fig 5. Photoluminescence spectra of LaSiBO₅:Tb³⁺, Eu³⁺.

(A) Excitation and emission spectra of La_0.93SiBO₅:0.05Tb³⁺, 0.02Eu³⁺phosphor. (b) Emission spectra of La_0.95-ySiBO₅:0.05Tb³⁺, yEu³⁺ phosphors. (c) Eu³⁺ concentration dependence of emission intensity.

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Fig 6 shows the energy level transition diagram of LaSiBO₅:Tb³⁺, Eu³⁺. When the energy level of Tb³⁺ ions transits to high excited states by external excitation, it usually reaches the ⁵D₄ energy level through nonradiative transition. Some of these electrons return to the ground state (⁵D₄→⁷F₆, ⁷F₅, ⁷F₄, ⁷F₃), resulting in the characteristic emission of Tb³⁺. Meanwhile, the energy of the Tb³⁺ energy level transition (⁵D₄→⁷F₆, ⁷F₅, ⁷F₄, ⁷F₃) is likely to be absorbed by the high excitation levels of Eu³⁺ (⁷F₀→⁵D₀, ⁵D₁), and red emission is observed through the ⁵D₀–⁷F_J (J = 1, 2, 3, 4) radiative transition. The emission of Tb³⁺ ions overlaps effectively with the excitation of Eu³⁺. In addition, the Tb³⁺ energy level at ⁵D₄ does not return to the ground state to produce green light emission but instead relaxes to the ⁵D₁ energy level and then to the ⁵D₀ energy level of Eu³⁺ through nonradiative transition. It then transfers to the ⁷F_J energy level through radiation transition, generating the red light emission of Eu³⁺. Thereafter, typical Tb³⁺ green emission and Eu³⁺ red emission occur simultaneously [23].

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Fig 6. Energy level transitions of Tb³⁺ and Eu³⁺ in La_1-x-ySiBO₅: Tb³⁺, Eu³⁺.

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The lifetime decay curves of the prepared phosphors are depicted in Fig 7(a) and 7(b) to confirm further the energy transfer between Eu³⁺ and Tb³⁺ in La_0.95-ySiBO₅:0.05Tb³⁺, yEu³⁺. The decay curves of the codoped rare earth ions conform to double exponential behavior. Decay lifetime can be calculated by using the following equation [24]:

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Fig 7. Decay curves of La_0.95-ySiBO₅:0.05Tb³⁺, yEu³⁺ phosphors.

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(3)

where I_(t) is the luminescence intensity at time t; A₁ and A₂ are decay constants; and τ₁ and τ₂ are the rapid and slow lifetimes of the fluorescence lifetime, respectively. The average lifetime (τ) can be calculated by using the following equation [25]:

(4)

The decay curve under the excitation of 377 nm and the emission of 544 nm is shown in Fig 7(a). The fluorescence lifetime of the phosphor without Eu³⁺ doping is 2.2225 ms. When Eu³⁺ concentrations increase to 0.001, 0.005, 0.01, 0.02, 0.03, and 0.05, τ decreases gradually to 2.0018, 1.9700, 1.9423, 1.5477, 1.4084, and 1.0057 ms, respectively. For further proof of the remarkable energy transfer from Tb³⁺ to Eu³⁺ in LaSiBO₅:Tb³⁺, Eu³⁺, the energy transfer efficiency (η) and energy transfer probability (P_t) can be calculated by using the following formulae:

(5)

(6)

where τ_so and τ_s represent the decay lifetime of Tb³⁺ in the absence and presence of Eu³⁺, respectively. η and P_t values increase significantly with the increase in Eu³⁺ concentration [26,27]. At the concentrations of 0.001, 0.005, 0.01, 0.02, 0.03, and 0.05, the η values of Eu³⁺ are 9.93%, 11.36%, 12.61%, 30.36%, 36.63%, and 54.75%, respectively, and the P_t values are 4.97%, 5.77%, 6.50%, 19.62%, 26.01%, and 54.44%, respectively. Therefore, energy has transferred from Tb³⁺ to Eu³⁺. The decay curves of the La_0.95-ySiBO₅:0.05Tb³⁺, yEu³⁺ phosphors at 616 nm emission and 393 nm excitation are shown in Fig 7(b). When the Eu³⁺ doping concentrations are 0.001, 0.005, and 0.01, the corresponding lifetimes increase markedly to 1.6160, 1.9520, and 2.0718 ms, indicating Tb³⁺→Eu³⁺ energy transfer [28]. When the Eu³⁺ doping concentrations are 0.02, 0.03, and 0.05, the corresponding lifetimes are 2.0878, 2.0823, and 2.0645 ms. The decrease in fluorescence lifetime is small because of the slow decrease in luminous intensity from Tb³⁺ that hinders energy transfer. The critical distance (R_C) is an important index for analyzing the energy transfer mechanism between luminous centers. The Tb³⁺ → Eu³⁺ energy transfer can occur through exchange interactions or electro–multipolar interactions. R_C can be approximated by employing the Blasse formula (1). Xc is the total critical concentration of Tb³⁺ and Eu³⁺. It is a part of the exchange interaction mechanism for R_C < 5 Å and a multipolar interaction mechanism for R_C > 5 Å. The sample La_0.93SiBO₅:0.05Tb³⁺, 0.02Eu³⁺ has V = 265 Å³, X_C = 0.07, and N = 6. R_C was calculated as 10.64 Å > 5 Å. The electrical multipole interaction is therefore responsible for energy transfer from Tb³⁺ to Eu³⁺.

Fig 8 shows the temperature-dependent emission spectra of the La_0.92SiBO₅:0.05Tb³⁺, 0.03Eu³⁺ phosphor. The shape of the emission spectra does not change during heating. The characteristic emission intensities of Tb³⁺ (544 nm) and Eu³⁺ (616 nm) in the La_0.92SiBO₅:0.05Tb³⁺, 0.03Eu³⁺ phosphor at 150 °C have decreased to 82.97% and 84.12% of the initial intensities at 25 °C, respectively. The characteristic emission intensities of Tb³⁺ (544 nm) and Eu³⁺ (616 nm) in the La_0.92SiBO₅:0.05Tb³⁺, 0.03Eu³⁺ phosphor at 250 °C have decreased to 77.18% and 67.72% of the initial intensities at 25 °C, respectively. Therefore, this phosphor has good thermal stability for LED applications. The quantum efficiency (QE) is also a critical performance parameter for phosphors used in LEDs. The thermal stability and QE value of phosphor La_0.92SiBO₅:0.05Tb³⁺, 0.03Eu³⁺ are better than those of Ca₃Gd(AlO)₃(BO₃)₄:Tb³⁺, Eu³⁺ [21] and Sr₃Sc(PO₄)₃:Tb³⁺, Eu³⁺ [29].

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Fig 8. Temperature-dependant emission spectra of La_0.92SiBO₅: 0.05Tb³⁺, 0.03Eu³⁺ phosphor.

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Fig 9 shows the CIE chromaticity diagram of La_1-x-ySiBO_5:x0.05Tb³⁺, yEu³⁺ drawn with CIE 1931 software (E_x = 377 nm). The chromaticity coordinates are given in the inset table. The chromaticity coordinates can be changed from green A (0.2948, 0.5854) to yellow E (0.4639, 0.4546) and then to red H (0.6378, 0.3414) by controlling the concentration of Tb³⁺/Eu³⁺. Therefore, the samples have potential applications in multicolor displays and W-LEDs.

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Fig 9. CIE diagram and luminous photos of La_0.95-ySiBO₅: 0.05Tb³⁺, yEu³⁺ phosphors.

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4. Conclusions

A series of LaSiBO₅:Tb³+, LaSiBO₅:Eu³+ and LaSiBO₅:Tb³+, Eu³+ phosphors was synthesized through high-temperature solid-state reaction. XRD results show that the phosphors have pure-phase crystal structures and uniform particle sizes suitable for LED packaging. Among the phosphors, the La_0.93SiBO₅:0.05Tb³+, 0.02Eu³+ phosphor has the strongest luminous intensity. The red and green emission intensity ratio of the La_1-x-ySiBO₅:xTb³+, yEu³+ phosphors decreases with the increase in Eu³+ concentration. Therefore, color tone can be effectively adjusted by controlling the doping concentrations of Eu³+ and Tb³+ ions. When the concentration of Tb³+ is 0.05 and that of Eu³+ increases from 0.005 to 0.05, the emission intensity of Tb³+ decreases gradually, whereas that of Eu³+ increases gradually. In addition, color changes from green to yellow and then to red. The results show that the LaSiBO₅:Tb³+, Eu³+ phosphors exhibit effective adjustable emission and NUV excitation and can be used as fluorescence conversion materials for display and LED applications.

Supporting information

S1 Data. Minimal raw data collection.

https://doi.org/10.1371/journal.pone.0344199.s001

(XLS)

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Figures

Abstract

1. Introduction

2. Materials and methods

2.1. Preparation

2.2. Characterization

3. Results and discussion

4. Conclusions

Supporting information

S1 Data. Minimal raw data collection.

References