Doping Concentration Of Eu3 Research Articles

Structural, optical and morphological properties of Eu rare earth doped WO3 nanoparticles enhanced photocatalytic for waste water treatment and antibacterial activities

In this paper, summarise the characterization and synthesis of the pure and Eu:WO3 nanoparticles and their applications in photocatalytic and antibacterial activity. The monoclinic phase confirmed by the XRD analysis of the prepared specimens. SEM and HR-TEM scrutiny revealed nanoplate morphology scrutiny. EDS and XPS scrutiny confirmed the composition of elements of Eu, O, and W. FTIR analysis likely used for additional confirmation of functional groups. UV–Vis Analysis determined the band gap energy (Eg) of the nanoparticles, which decreased with raising the concentration of Eu doping. Optical properties of the band gap energy decreased with raising the concentration of Eu doping. Photocatalytic activity of the nanoparticles exhibited high photocatalytic activity, with a 95.3 % methylene blue (MB) dye split when exposed to visible light. The Eu:WO3 (7 wt%) nanoparticles showed the best photocatalytic property within 120 min. The Eu:WO3 (7 wt%) nanoparticles showed the maximum antibacterial efficiency against Staphylococcus aureus, with a zone of embarrassment of 19 mm. Overall, the study demonstrates the successful synthesis of Eu-doped WO3 nanoparticles and their potential applications in photo catalysis and antibacterial activity, with promising results particularly at higher Eu doping concentrations.

Adjustable emission and energy transfer in perovskite structure La2MgSnO6: Eu3+, Bi3+ phosphors for multifunctional applications

A series of Eu3+/Bi3+ single and co-doped La2MgSnO6 phosphors are synthesized by the solid-state method. The crystal structure, optical properties, energy transfer processes, and thermal stability of phosphors are investigated systematically. Under 331 nm excitation, both the orange-red emission of Eu3+ ions ranging from 500 to 750 nm and the blue emission band centered at 403 nm are observed in the La2MgSnO6:Eu3+, Bi3+ samples. With the doping concentration of Eu3+ changing, the emission of La2MgSnO6:Eu3+, Bi3+ phosphors can be adjusted from blue (0.219, 0.350) to orange-red light (0.644, 0.341) in chromaticity coordinate. Furthermore, the security ink prepared by phosphors can be effectively used for encryption writing and anti-counterfeit marking. Additionally, the latent fingerprint developed using La2MgSnO6: Eu3+, Bi3+ phosphor demonstrates excellent contrast and sensitivity.

Eu Doping in the GdCd7.88 Quasicrystal and Its Approximant Crystal GdCd6.

The effect of Eu doping in the Tsai quasicrystal (QC) GdCd7.88 and its periodic 1/1 approximant crystal (AC) GdCd6 are investigated. This represents the first synthesis of Eu-containing stable QC samples, where three samples with the final composition Gd1-xEuxCd7.6±α at Eu doping concentrations x = 0.06, 0.13, and 0.19 are obtained (α ∼ 0.2). They are compared to two 1/1 ACs with compositions Gd1-xEuxCd6 (x = 0.12, 0.16). In addition, a new type of 1/1 AC, differing only by the inclusion of extra Cd sites unique to the Eu4Cd25 1/1 AC, has been discovered and synthesized for the concentrations Gd1-xEuxCd6+δ (x = 0.25, 0.33, 0.45, 0.69, 0.73, and 0 < δ ≤ 0.085). Due to the preferred cube morphology of its single grains, we refer to them as c-type 1/1 ACs and to the conventional standard ones as s-type. In both QCs and s-type ACs, the Eu content appears to saturate at a concentration of ∼20%. On the other hand, any Gd| Eu ratio is allowed in the c-type ACs, varying continuously between GdCd6 and Eu4Cd25. We describe and contrast the changes in composition, atomic structure, specific heat, and magnetic properties induced by Eu doping in the quasicrystalline phase and the s-type and c-type 1/1 ACs. By comparing our results to the literature data, we propose that the occupancy of the extra Cd sites can be used to predict the stability of Tsai-type quasicrystalline phases.

Preparation of red fluorescent materials for a solution process using europium-doped benzoguanamine

This study aims to develop a novel, efficient, and stable red-emitting material using benzoguanamine in which europium (Eu) is doped. We have demonstrated a simple, low-cost, gram-scale manufacturing process via an anneal synthesis method. By changing the Eu-doping concentration from 1 to 20 wt%, we found that the sample containing a Eu-doping concentration of 10 wt% shows the maximum photoluminescence quantum yield peak of 13.7%. Additionally, we confirmed the characteristic luminescence peaks of Eu ions. We also achieved a sharp red emission with a high color purity and a half-peak width of 13 nm. Furthermore, it exhibits high solubility in organic solvents, facilitating its application through wet processes. This new red-emitting material may present a promising solution for cost-effectively fulfilling the demand in flat panel displays and illumination light sources.

Narrow-band cyan and green dual-peak emission Rb2KNa(Li3SiO4)4: Eu2+ phosphor for full-spectrum w-LED: Synthesis, structure, and spectrum regulation

Full-spectrum white LED (w-LED) lighting is primarily achieved through the combination of multiple-color phosphors excited by the chip, and making the development of efficient multi-color phosphors based on single matrix is an excellent choice for full-spectrum w-LED. In this paper, a series of Rb2KNa(Li3SiO4)4: xEu2+ (0.1 % ≤ x ≤ 15 %) phosphors were successfully synthesized via high-temperature solid-state reaction with varied Eu2+ concentration. At low doping concentration, the Eu2+ ions exhibit primarily green emission at 530 nm in the phosphor. However, as the doping concentration of Eu2+ ions increase, the emission spectrum undergoes a significant transformation. A cyan emission occurs at 478 nm, resulting in the spectral conversion from a green single-peak emission to a dual-peak emission of cyan and green. The spectral conversion is attributed to the changes in the positioning of Eu2+ ions within the crystal lattice. The obtained phosphors demonstrate excellent thermal stability and can be utilized in w-LED devices. After encapsulation with a blue LED chip, it achieves a color rendering index of 91.8 and a correlated color temperature of 4085 K, showcasing its significant application value in the field of full-spectrum w-LED.

Exploring the Photoluminescence Property, Photocatalytic Efficiency, and Antibacterial Activity of Eu-Doped ZnO/SnO2 Heterostructure

In this study, nanocomposites of ZnO–SnO2 doped with Eu ions were synthesized by sol-gel method. The samples show the co-existence of hexagonal ZnO and tetragonal SnO2 crystallographic phases as observed from X-ray diffractometry studies. Eu doping facilitates the grain growth as the average grain size is found to increase with the increase in Eu dopant concentration. Surface morphology of the samples also gets altered with Eu doping with EDAX measurement giving the confirmation of existence of elements like Zn/Sn/Eu. FTIR measurement specifies the appearance of peaks linked with functional groups like Zn–O, Sn–O and O–H. Photoluminescence study shows the evolution of characteristic emissions of Eu ions (5D0→ 7F1, 5D0→ 7F2 and 5D0→ 7F3). Photodegradation of toxic environmental dyes like Congo red and methylene blue was executed and the efficiency of degradation was estimated under visible light illumination. The presence of Eu3+ ions in ZnO/SnO2 helps to enhance the degradation efficiency by facilitating to form Z- scheme heterojunctions between ZnO and SnO2. This allows the delay in recombination rate of the photoinduced electron/hole pairs. The antibacterial behavior of the prepared nanocomposites against E. coli and S. aureus has also been studied in detail which demonstrates improved antibacterial efficiency of the samples.

Ratiometric mechanoluminescence in LiSrPO4:Eu2+/Eu3+ for stress sensing: Dopant concentration dependent sensitivity

Ratiometric mechanoluminescence (ML) has been recently proposed for stress-sensing, which is regarded to be superior to the traditional ML-intensity based sensing route in terms of accuracy and cycle stability. The dual-activator strategy to realize the ratiometric ML takes advantage of instantaneous change of local crystal field environment induced by stress, where the structural characteristics of host are supposed to play major role. Herein, LiSrPO4:Eu2+/Eu3+ phosphors have been explored to realize the ratiometric ML, with the focus on the influence of Eu dopant concentration on the sensitivity of the stress-dependent ratiometric ML. The dependence between the dopant concentration and sensitivity can be interpreted in terms of host phase structure evolution with dopant concentration.

Enhanced light output of Eu, O-codoped GaN caused by reconfiguration of luminescent sites during post-growth thermal annealing

Luminescence efficiency of Eu-related emission from Eu, O-codoped GaN (GaN:Eu, O) strongly depends on the local structure of Eu ions. Growth at relatively low temperature (∼960 °C) not only enables high Eu doping concentration but also elevates Eu-clustering due to its low diffusion coefficient, which results in formation of a large number of inefficient luminescent sites. We have studied the impact of post-growth thermal annealing at high temperatures on elimination of Eu clusters by photoluminescence measurements. These clarify that thermal annealing at high temperatures induces changes in the structural conformation and converts inefficient luminescent sites to efficient ones. As a result, the sample annealed at 1100 °C shows increased luminescence efficiency with a maximum of 5.1 times that of the as-grown sample. Post-growth thermal annealing offers a way to improve the efficiency of GaN:Eu, O further for practical application in III-nitride-based monolithic three-primary colors' light-emitting diodes.

Role of site selective substitution, magnetic parameter tuning, and self heating in magnetic hyperthermia application: Eu-doped magnetite nanoparticles.

Various researchers have provided considerable insight into the fundamental mechanisms behind the power absorption of single-domain magnetic nanoparticles (MNPs) in magnetic hyperthermia applications. However, the role of all parameters pertinent to magnetic relaxation continues to be debated. Herein, to explore the role of magnetic anisotropy with the site selective substitution related to magnetic relaxation has generally been missing, which is critically essential in respective of hyperthermia treatment. Our study unravels contradictory results of rare earth (RE) interaction effects in ferrite to that of recently reported literature. Despite this, rare earth atoms have unique f-block properties, which significantly impact the magnetic anisotropy as well as the relaxation mechanism. Here, we use appropriate Eu doping concentration in magnetite and analyze its effect on the matrix. Furthermore, a positive SAR can effectively reduce the relative dose assigned to a patient to a minimal level. This study indicates that the introduction of Eu ion positively influenced the heating efficiency of the examined magnetite systems.

Excellent yellow emission of Si3N4:Eu nanorods derived from waster silicon with better thermal stability for white LEDs

The core issue of light emitting diodes (LEDs) for actual application is the thermal stability of phosphors. Silicon nitride (Si 3 N 4 ) is generally recognized as especially important structural material due to its excellent mechanical properties at extreme high temperature. In this work, Si 3 N 4 : Eu was demonstrated to be an excellent luminescence functional material for LEDs. The discarded corner-waster silicon raw material was utilized to act as the precursor. The Si 3 N 4 :Eu phosphor was synthesized by a facile nitriding process at elevated temperature. The pure α-Si 3 N 4 :Eu nanorods were successfully obtained by adjusting the doping concentration of Eu. It is coexistence with mixed-valence (divalent and trivalent) for Eu in α-Si 3 N 4 according to X-ray photoelectron spectroscopy. The synthesized α-Si 3 N 4 :Eu nanorods showed bright yellow under the excitation of 365 nm (UV) and white luminescence by 460 nm chip (Blue). The Si 3 N 4 :Eu nanorods possess excellent thermal stability, maintains nearly 70% of the origin intensity even at temperatures over 300 °C. The Si 3 N 4 :Eu nanorods demonstrated comparable performance to commercial YAG:Ce 3+ (YAG). Moreover, the long-term thermal stability of Si 3 N 4 :Eu nanorods is superior to commercial YAG, revealing the enhanced service performance. This work not only presents a facile Si 3 N 4 :Eu nanorods green synthesis route from waste utilization, but also offers an enhanced service performance for the high temperature LEDs application.

Luminescence Properties of Eu-Doped BaLaAlO&lt;sub&gt;4&lt;/sub&gt; Phosphors for Solid State Lighting

In this study Barium Lanthanum Aluminate BaLaAlO4 and BaLaAlO4:xEu red phosphors were produced at different x at.% Eu concentration (x = 0,1,3,5 and 7 at.% of Eu) by combustion synthesis method and post-annealing. The X-ray diffraction (XRD) patterns shows that all samples present the orthorhombic phase (JCPDS # 44-0164). Scanning electron microscopy (SEM) shows that the grains size diminished and then increases as a function of Eu-doping concentration addition. Photoluminescence spectra of the samples, under UV excitation, show a maximum strong red emission at lem= 615 nm attributed to the 5D0®7F2 Eu3+ ion transition. The Eu-doped BaLaAlO4 sample that present the highest luminescence intensity was with the x= 1.0 at.% of Eu doping concentration. The quenching in photoluminescence spectra was detected for the Eu doping concentrations of x= 5 and 7 at%, which was ascribed to due to dipole-quadrupole (d-q) interactions. Because the strong red emission of Eu-doped BaLaAlO4 phosphor it could be used UV activated LEDs.

Production, characterization, and photocatalytic properties of Eu:Y2O3 nanopowders

AbstractEu:Y2O3 nanophosphors (NPs) with different Eu concentrations (3, 5, and 7 at%) were successfully synthesized via the sol–gel method. All synthesized powders had a cubic bixbyite‐type crystal structure with space group Ia‐3. It was observed they had agglomerated sphere‐like morphologies. In addition, a neck formation between the particles, which was the result of the sintering effect at the increasing calcination temperature, was also observed by scanning electron microscopy analysis. Raman and X‐ray photoelectron spectroscopy (XPS) analyses confirmed that the Eu dopant entered into the Y2O3 host. The XPS peak positions shifted to relatively higher binding energy values with increasing dopant concentration and calcination temperature. Increasing Eu dopant concentration in the host structure also increased the 3+ valence ions. The band gap values of the NPs varied between 4.30 and 4.54 eV. The powders doped with 5 at% Eu was active as photocatalysts and the powders that were synthesized at 800°C exhibited highly photocatalytic activity.

Microstructure and photoluminescence of Eu-doped Sr3Al2O6 phosphors calcined with and without H3BO3 flux

The development of highly efficient and stable red phosphors fabricated using cost-effective and simple mass-production methods is essential for applications in future displays and lighting devices. Herein, we investigate the phase formation, microstructures, and luminescence properties of Sr3Al2O6:Eu powders synthesized using a solid-state reaction process. Single-phase Sr3Al2O6:Eu phosphors exhibiting excellent photoluminescence with color-tunable orange-red and red colors under different excitation wavelengths were successfully synthesized. The optimal Eu doping concentration of Sr3Al2O6, yielding strong photoluminescence with phase stability, was 5 at. %, with the concentration quenching point determined by systematic exploration. The addition of H3BO3 as a flux significantly affected the grain size and improved the emission intensity of the synthesized (Sr0.95Eu0.05)3Al2O6 phosphors up to 12.5 wt %, while secondary phases were formed at higher flux concentrations. The photoluminescence intensities of the 5D0 → 7F1 and 5D0 → 7F2 transitions of 12.5 wt % H3BO3 added (Sr0.95Eu0.05)3Al2O6 increased by 3.4 and 4.2 times compared with the flux-free powders under the 394 nm-wavelength excitation, while the decay time decreased from 7.35 to 5.40 ms. Our report of the enhanced photoluminescence intensity and shortened decay time of (Sr0.95Eu0.05)3Al2O6 phosphors following the flux addition is promising for production of single-phase phosphors emitting multi-colors, which is needed for optical devices activated by various excitation frequencies.

Room Temperature Synthesis of Various Color Emission Rare-Earth Doped Strontium Tungstate Phosphors Applicable to Fingerprint Identification

Crystalline SrWO4 was synthesized at room temperature using a co-precipitation method. To use the SrWO4 as a phosphor, green and red phosphors were synthesized by doping with Tb3+ and Eu3+ rare earth ions. The synthesized samples had a tetragonal structure, and the main peak (112) phase was clearly observed. When the sample was excited using the absorption peak observed in the ultraviolet region, SrWO4:Tb3+ showed an emission spectrum of 544 nm, and SrWO4:Eu3+ showed an emission spectrum of 614 nm. When Tb3+ and Eu3+ ions were co-doped to realize various colors, a yellow-emitting phosphor was realized as the doping concentration of Eu3+ ions increased. When the synthesized phosphor was scattered on a glass substrate with fingerprints, as used in the field of fingerprint recognition, the fingerprint was revealed by green, red, and yellow emissions in response to a UV lamp.

Photoluminescence properties and energy transfer in the Sm3+ and Eu3+ co-doped Ca3Bi(PO4)3 red phosphor

Red phosphors play a vital role in improving the color quality and luminous efficiency of white light-emitting diodes (w-LED). However, it is still a challenge to develop red phosphors with higher efficiency, higher color purity, and better matching near-ultraviolet (n-UV) chips. In this paper, a series of Sm3+, Eu3+ co-doped Ca3Bi(PO4)3 (CBP) were successfully prepared by the high temperature solid-state reaction method. The crystal structure, photoluminescence properties, and energy transfer mechanism were investigated in detail. The maximum doping concentration of Eu3+ in CBP was confirmed to be 30 mol% in this research considering the structural instability with higher doping concentration. Under 393 nm n-UV excitation, CBP: 8 mol% Sm3+, 25 mol% Eu3+ phosphor exhibit excellent red-lighting emission at 612 nm with high color purity of 99.28 %. More impressively, the effective excitation wavelength of Sm3+, Eu3+ co-doped CBP phosphors is extended to 391–403 nm due to energy transfer from Sm3+ to Eu3+. Moreover, the energy transfer mechanism is rationalized through dipole–dipole interaction as indicated via decay kinetics studies. The fabricated w-LED emits white light, which has high color rendering index (CRI = 86.0) at color coordinate temperature CCT = 6985 K and luminous efficiency (66 lm/w). The phosphor shows excellent thermal stability, and the fluorescence intensity to temperature 423 K can retain 75.98 % of its initial value of room temperature. These results indicate that this phosphor with high-efficiency red-emitting is a promising candidate as a red component for n-UV LED application.

An Investigation of the optoelectrical properties of n-TiO2Eu/p-Si heterojunction photodiode

In the present investigation, titanium dioxide (TiO2) and Euphorium (Eu) doped TiO2 films were deposited on both glass and n-Si substrates via employing sol-gel spin coating technique to characterize optical, morphological, chemical features and scrutinize their heterojunction applications. The atomic force microscope (AFM), Ultraviolet-visible (UV-VIS) and Raman studies were conducted to inspect the morphological, optical, chemical, and crystal phase properties of thin films, respectively. The optical band gap of TiO2 films widened from 3.40 eV to 3.44 eV with increasing Eu doping concentration. The Raman analyses displayed that the deposited TiO2 films were in the anatase phase. The AFM images indicated Eu substitution influences the surface structure of the fabricated films. The optoelectrical properties of the fabricated heterojunction structures were determined under dark and various illumination intensities. When the optoelectrical properties of the obtained diodes were examined, it was realized that while the ideality factor (η) and series resistance (RS) decreased, the barrier height (ΦB), photosensitivity and photoresponse parameters increased with the optimum Eu concentration. The results underscore that Eu substitution into TiO2 structure influences structural, optical, and electrical parameters. Thus, the Eu material could be used as a potential candidate to improve the optoelectrical performance of n-TiO2/p-Si.

Investigation on the optical sensing behaviors in single Eu3+-activated Sr2InSbO6 phosphors under green light excitation

The sensing sensitivities of the Sr2InSbO6:Eu3+ phosphors with different doping concentrations were investigated based on the temperature-dependent decay curves. The crystal and electronic structure were studied by the X-ray diffractometer (XRD), Rietveld refinement, and X-ray photoelectron spectroscopy (XPS). In addition, the luminescent behaviors (e.g., photoluminescence spectra, concentration quenching, thermal stability, and luminescent dynamic) were investigated under the green light excitation (λex = 529 nm). The dominated peak was assigned to the 5D0 → 7F1 transition emitting an orange-red emission. Moreover, the obtained sample exhibited excellent thermal stability that the emission intensity remained 91.61% at 425 K. Eventually, the relative sensing sensitivity of the Sr2EuSbO6 phosphor was 0.766% K−1 and the doping concentration of Eu3+ ions greatly affected the sensing sensitivity. This work is the first time to investigate the single Eu3+-activated luminescent materials under the green light excitation.

Rational design, fabrication, optical properties and high-efficiency visible-light photocatalytic degradation performance for organic pollutants of Eu:Bi2WO6/CdS nanostructures

Over the past few years, semiconductor materials (especially bismuth tungstate) exhibiting unique environment purification and energy conversion capacities arouse huge attention as impacted by issues of environmental pollution and energy shortage, whereas its application is restricted by the problems of high carrier recombination rate and unsatisfactory degradation efficiency. In this study, Eu:Bi 2 WO 6 nanostructures containing Eu ions of different concentrations were synthesized with a chemical solution method, and CdS was generated on the surface of Eu:Bi 2 WO 6 nanostructures in situ epitaxial to synthesize the Eu:Bi 2 WO 6 /CdS composites. The effects of Eu doping concentration on the crystal structure, chemical composition, local structure, optical properties and visible-light photocatalytic properties exhibited by Eu:Bi 2 WO 6 /CdS nanostructures were studied more specifically, and the Eu doping behavior on the improvement mechanisms for optical and photocatalytic performance exhibited by Eu:Bi 2 WO 6 /CdS nanostructures was clarified. The robust PL emission peak at about 390 nm and weak emission peak at nearly 450 nm are attributed to the exciton emission and defect state of Bi 2 WO 6 /CdS nanostructure, respectively. As indicated from the mechanism insights, the reasonable introduction of Eu 3+ could alter the band gap of the photocatalyst, and the epitaxial CdS could decrease the recombination probability of electron and hole in the Bi 2 WO 6 /CdS, while improving the photocatalytic activity. This study supplies new occasions for rational excogitation and better comprehending of atomic-scale complicated structures for applications in numerous fields (e.g., energy and environmental protection).

Synthesis and luminescent properties of rare earths doped Gd&lt;sub&gt;2&lt;/sub&gt;Te&lt;sub&gt;4&lt;/sub&gt;O&lt;sub&gt;11&lt;/sub&gt; tellurite phosphors

A series of rare earth Dy&lt;sup&gt;3+&lt;/sup&gt;, Tb&lt;sup&gt;3+&lt;/sup&gt;, Eu&lt;sup&gt;3+&lt;/sup&gt; singly doped Gd&lt;sub&gt;2&lt;/sub&gt;Te&lt;sub&gt;4&lt;/sub&gt;O&lt;sub&gt;11&lt;/sub&gt; (GTO) tellurite phosphors with intrinsic polarity are prepared by hydrothermal method. The phase structures, morphologies and thermal stabilities of these phosphors are characterized. Their luminescence properties are tested in detail. The results show that all those phosphors are crystalized into single phase of digadolinium tellurite with short rod-like shape. The maximum size in the axial direction is microns. The phosphor has good thermal stability. For the GTO:Dy&lt;sup&gt;3+&lt;/sup&gt;, the fluorescence emission under UV excitation is mainly located in the yellow-green region. The optimal doping concentration corresponding to the strongest excitation and emission is 2.5%, and the CIE color coordinates are (0.39, 0.43). The fluorescence decay curve shows that the lifetime of the GTO:Dy&lt;sup&gt;3+&lt;/sup&gt; on &lt;sup&gt;4&lt;/sup&gt;F&lt;sub&gt;9/2&lt;/sub&gt; energy level decreases gradually with doping concentration of Dy&lt;sup&gt;3+&lt;/sup&gt; increasing, which may be related to the cross relaxation (CR) between Dy&lt;sup&gt;3+&lt;/sup&gt; ions. For the GTO:Eu&lt;sup&gt;3+&lt;/sup&gt;, the fluorescence emission under UV excitation is mainly located in the red region and orange-red region. The emission intensity is enhanced with the doping concentration of Eu&lt;sup&gt;3+&lt;/sup&gt; increasing. When the doping concentration is 10%, the CIE color coordinates are (0.62, 0.38), which are located in the orange-red region with high color purity. The fluorescence lifetime of Eu&lt;sup&gt;3+&lt;/sup&gt; on &lt;sup&gt;5&lt;/sup&gt;D&lt;sub&gt;0&lt;/sub&gt; energy level is hardly affected by the change of Eu&lt;sup&gt;3+&lt;/sup&gt; doping concentration. For the GTO:Tb&lt;sup&gt;3+&lt;/sup&gt;, with the increase of the Tb&lt;sup&gt;3+&lt;/sup&gt; concentration, the fluorescence emission under UV excitation changes from blue-violet region to yellow-green region, which can be ascribed to the influence of CR between Tb&lt;sup&gt;3+&lt;/sup&gt; ions. The fluorescence decay behavior reveals that the Tb&lt;sup&gt;3+&lt;/sup&gt; ions on &lt;sup&gt;5&lt;/sup&gt;D&lt;sub&gt;4&lt;/sub&gt; excited state may undergo energy transfer and reabsorption, which can deviate the fluorescence decay from the single exponential model. When the concentration of Tb&lt;sup&gt;3+&lt;/sup&gt; is 0.5%, the sample exhibits white light emission with the CIE color coordinates of (0.33, 0.35) and color rendering index of 86. The measurements of temperature-dependent emission spectra show that the above-mentioned phosphors have good luminescent thermal stability. The internal quantum efficiencies (IQEs) of those three types of phosphors are measured, and the IQE of GTO:Eu&lt;sup&gt;3+&lt;/sup&gt; is better than those of GTO:Dy&lt;sup&gt;3+&lt;/sup&gt; and GTO:Tb&lt;sup&gt;3+&lt;/sup&gt;. There is still much room for improvement in the luminescent performance of all these phosphors. These phosphors have potential to be used in UV-excited white LEDs.

Enhanced photovoltaic effect derived from the regulation of Jahn–Teller distortion in a lattice compensation structure

Larger remanent polarization and lower optical bandgap play crucial roles in the ferroelectric photovoltaic effect. However, they are always mutually conditioning for almost perovskite material based orbital hybridization theories. Here, we design a lattice compensation structure, in which Eu was incorporated to strengthen J–T distortion of Mn–O octahedral in BiFeO3–BiMnO3 solid solution films due to relieved degeneracy; in turn, the distortion compensates the lattice shrink derived from Eu doping. A narrow bandgap of 2.24 eV and a large remanent polarization of 93.7 μC/cm2 are achieved by lattice compensation modification. Compared with the film with an Eu doping concentration of 0.04, the open-circuit voltage and the short-circuit current of the film with 0.08 doping concentration are increased by 4.6 and 2.7 times, respectively, showing remarkable ferroelectric photovoltaic response. This work identifies an alternative strategy to enhance ferroelectric photovoltaic effects by regulating J–T distortion and lattice compensation.