High CRI Research Articles

A 1D helical eco-friendly Mn(II) halide coordination polymer: Luminescent properties involving resonant energy transfer and magnetic characterization

In the present work, we discuss the synthesis of nontoxic Mn(II) halide coordination polymer and explore the potential light emission properties for solar-cell devises through experimental and computational studies. The crystal structure was unveiled through Single Crystal Diffraction, whereas physical properties were investigated by means of thermal, spectroscopic, magnetic, optical and photoluminescence measurements. The observed left-right handed helical structure is built up from an infinite 1-D chains of Mn(II) octahedra. The polymeric network is stabilized through inter-molecular hydrogen bonding interactions and π···π face-to-face interactions. Furthermore, ferro-antiferromagnetic ordering has been proven through magnetic measurements. A deep investigation of the photoluminescence study reveals the presence of a bright bluish light emission with corresponding CIE color coordinates of (0.27, 0.35), CCT value of 8092 K and a very high CRI value of 96. The origin of this intense light emission is mainly attributed to the occurrence of the resonant energy and charge transfer processes between Triazolate ligand and inorganic Mn–Cl sub-lattices. Such behavior leads to the conversion of Frenkel excitons localized within the organic part to Mott-Wannier excitons localized in inorganic clusters. Based on these results, we strongly believe that the elaborated material can be a promising candidate for eco-friendly electronic applications.

A novel highly thermal-stable red-emitting CaGdSbWO8:Eu3+ phosphor with scheelite structure for high CRI w-LEDs,security ink, and latent fingerprint

Recently, rare-earth doped phosphors have been newly developed and applied in hot issues such as phosphor-converted light-emitting diodes (pc-LEDs), anti-counterfeiting, and fingerprint visualization. Herein, an Eu 3+ -activated CaGdSbWO 8 (CGSW) red phosphor was synthesized by a high-temperature solid-state reaction. The phosphors can exhibit narrow red-light emission at 614 nm due to the electric dipole transition 5 D 0 → 7 F 2 of Eu 3+ . Impressively, this phosphor has excellent thermal stability, its emission intensity of optimum sample doped with 0.30 Eu 3+ remained 90.61% at 420 K and thermal quenching temperature exceeds 480 K. The Commission International del’Eclairage (CIE) chromaticity coordinates of CGSW:0.30Eu 3+ are (0.662, 0.338) with a high color purity (98.5%). The fabricated white light diode (w-LED) has a high color rendering index (91.4) and a low correlated color temperature (4986 K) with CIE coordinates (0.343, 0.327). Further experimental results showed that the prepared security ink can be applied to anti-counterfeit labels and information encryption. The latent fingerprint developed by CGSW:0.30Eu 3+ phosphor present the excellent selectivity and contrast. The level 1–3 structural characteristics of latent fingerprints could be well identified under ultraviolet irradiation. Therefore, the Eu 3+ -activated CGSW red-emitting phosphor has broad application prospects due to its excellent luminescence properties. • Novel CaGdSbWO 8 :Eu 3+ phosphors have been synthesized via high-temperature solid-state method. • The CaGdSbWO 8 :Eu 3+ phosphors with scheelite structure have good thermal stability ( T 0.5 >480 K). • The w-LED fabricated by the phosphor exhibits a high CRI value of 91.4 and a good CCT of 4986 K. • The applications in security ink and latent fingerprint of CaGdSbWO 8 :Eu 3+ phosphors are investigated in details.

Continuous production of K2SiF6:Mn4+ red phosphor by green route synthesis method for warm WLEDs application

The K2SiF6:Mn4+ red phosphor has caused widespread concern in warm white light-emitting diodes (WLEDs) due to its unique broadband blue light absorption and narrow-band red emission. However, commercial K2SiF6:Mn4+ red phosphor inevitably needs to use extremely corrosive HF as a raw material, which will cause great harm to the environment and human beings. In this work, the K2SiF6:Mn4+ phosphor with highly uniform particle shape and size was successfully synthesized without using HF solution through microfluidic technology. The structure, morphology and photoluminescence properties of the K2SiF6:Mn4+ phosphors prepared in this work were systematically investigated and analyzed. The K2SiF6:Mn4+ phosphors synthesized by microfluidic technology are all cubic particles. The sample was the most uniform with a particle size of about 4.14 μm when the pipe diameter was 4 mm and the injection speed was 1000 μL/min, and the number of active Mn4+ in this sample is the largest according to the calculation results, resulting in its maximum luminous intensity. Finally, a warm WLED with low CCT (3379 K) and high CRI (Ra = 89.7) was fabricated by combining the as-prepared red K2SiF6:Mn4+ phosphor with yellow phosphor YAG:Ce3+ and blue LED chip. The results indicate that the K2SiF6:Mn4+ phosphor prepared by the proposed green continuous route is suitable for WLEDs.

The effects of silica-coated Y2O2S:Eu3+ red phosphor on the lighting properties of the light-emitting diode

The red phosphor Y2O2S:Eu3+ coated with silica (SiO2) nanocomposite was synthesized using the sol-gel method with dip-coating technique. The purpose of coating the poly (methyl methacrylate) (PMMA)-SiO2 composite on Y2O2S:Eu3+ phosphor’s surface is to protect the phosphor and improve its scattering ability. The three primary ingredients of coating composition include methyl methacrylate (MMA) monomer, tetraethyl orthosilicate (TEOS), and SiO2 nanoparticles. Via Mie scattering theory, the scattering of SiO2 is examined, which primarily determines the scattering of PMMA-SiO2-coated Y2O2S:Eu3+. The larger particles of SiO2 in the coating composite leads to better scattering properties. When being applied in the dual-film remote phosphor configuration of a LED, SiO2@Y2O2S:Eu3+ considerably enhances the CRI and the color quality scale (CQS). The highest CRI and CQS can be observed at approximately 85 and 74 with 23 %wt. and 26 %wt. the concentration of SiO2@Y2O2S:Eu3+, respectively. Neverthless, the illuminating beam of the package gradually declines as the concentration of SiO2@Y2O2S:Eu3+ go up, which might be ascribed to excessive scattering occurrences in the double-layer remote package.

Eu3+ heavily doped tellurite glass ceramic as an efficient red phosphor for white LED

To design a phosphor for near ultraviolet (n-UV) based white light emitting diodes (wLED) with low correlated color temperature (CCT) and high CRI, a series of highly Eu3+ activated tellurite samples was prepared. Glass ceramic (GC) containing Eu2Te6O15 microcrystals were obtained as a function of crystallization time from 0 to 4 h at 435 °C. X-ray diffraction (XRD) and cathodoluminescence measurement confirm the existence Eu2Te6O15 microcrystals in translucent glass ceramic, improving the luminescence properties of the samples. Upon 393 nm excitation two intense emission bands centered at 594 nm and 614 nm were observed with an increase of 200% for the crystallized samples at 435 °C for 4 h with respect to as-fabricated glasses. Radiometric properties of heavily (10 mol %) Eu3+ doped samples as a function of crystallization time were investigated and the maximum luminous efficacy (LE) obtained is 12.01 lm/W for a crystallization time of 4 h. A green phosphor (SrBaSiO4:Eu2+) on top of samples was used the construct a white light-emitting diode and the results show that the color coordinate temperature (CCT) can be tuned from 4729 K to 3405 K as crystallization time increase from 0 to 4 h with a diminishing of LE from 34.3 to 19 lm/W. The results show that tellurite glass and GC present enormous potential as phosphor converters in solid state lighting application.

Local structure distortion enhanced the emission intensity of KBaYSi2O7:Eu2+ phosphor for full-visible-spectrum LED lighting

Due to Eu2+ and Eu3+ ions often co-exist in the crystal lattices, the luminous intensity of some phosphors is limited greatly. In this work, we propose a crystal-site engineering approach to reduce Eu3+ to Eu2+ in the KBaYSi2O7 lattice through substitution of Ba2+ by Ca2+ or Sr2+. The mechanism between the local environmental regulation of the crystal structure around Eu2+ as well as the luminous intensity and thermal stability of the phosphor was systematically explored. The results of XRD, Rietveld refinement and EDX confirmed that Ca2+ and Sr2+ are dissolved into the crystal lattice effectively without changing the main phase structure. As a result, the luminous intensity of samples doped Ca2+ and Sr2+ increased by 39.7% and 41.2%, respectively. The mechanisms for such improvement is ascribed to the reduction of Eu3+ into Eu2+ under the lager volume of [EuO9]2 polyhedron. The treated samples exhibited relatively superior thermal stability with I150°C > 70%, indicating that doping with Ca2+ or Sr2+ have no effect on the thermal stability. A pc-WLED device fabricated by combining (Ba,Sr)2SiO4:Eu2+, (Ca,Sr)AlSiN3:Eu2+, BaSi2O2N2:Eu2+ and KBa0.86Ca0.1YSi2O7:Eu2+ with 380 nm chip exhibits CCT (5010 K) and high CRI (96.6). These results indicate that this phosphor has potential for applications in full-spectrum warm white lighting.

Contributing risk factors overview of high Castelli risk index-i of police officer: a cross-sectional study

Abstract Funding Acknowledgements Type of funding sources: None. Background Dyslipidemia is a major risk factor of cardiovascular disease, many studies have shown that lipid ratios can be used to predict cardiovascular disease more effectively than individual lipid levels. Objective/Aims This study aims to evaluate the potential risk factors contributing to high Castelli Risk Index–I (CRI–I) in police officer. Methods This observational-descriptive with cross-sectional design study enrolled 3,018 members of East Java police officer. Data was obtained using physical and laboratory examinations that includes systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), low density lipoprotein-C (LDL–C), high density lipoprotein–C (HDL–C), triglyceride (TG), total cholesterol (TC). BMI was classified into < 25 (normal BMI) and > 25 (higher than normal BMI). High blood pressure (BP) was defined as SBP ≥ 140 mmHg and/or DBP ≥ 90 mmHg. CRI-I was calculated using the formula of TC/HDL–C and was defined >5 as at risk and <5 as normal. Statistics were performed on SPSS version 25 and cross-tabulation test was performed on the CRI–I, BP, and BMI in a table form. Result 927 (30.7%) respondents had a CRI–I score > 5. Result of the cross-tabulation test of the high CRI–I score with the physical examination showed association with high BP (OR=1.394; p=0.0), and higher than normal BMI (OR=1.184; p=0.043). Conclusion There was a significant associations between high CRI-I and high blood pressure and higher than normal BMI among a clinical sample of Police Officers.

Highly thermally stable red phosphor-in-glass films for high-power laser lighting

The development of CASN (CaAlSiN3: Eu2+) fluorescent materials with excellent quantum efficiency and low thermal quenching performance is an effective way to improve the quality of white light. In this research, a CASN-PiG film with a high external quantum efficiency (56%) and high thermal conductivity (12.935 W m−1 K−1) was prepared by co-firing CASN phosphors and glass powder on a sapphire substrate. The surface structure and optical properties of the CASN-PiG (phosphor-in-glass) film were studied in detail. Furthermore, the CASN-PiG film can even survive 5.3 W/mm2 blue laser excitation. Surprisingly, the blue laser diode is combined with the CASN-PiG film to obtain a high luminous flux of 164 lm. Importantly, the CASN phosphors is compounded with Ce:YAG phosphors to prepare a high CRI (85) PiG film with a luminous flux of 845 lm and a luminous efficiency of 190 lm/W, realizing high-quality white laser lighting.

Narrow-Band Red-Emitting Phosphors with High Color Purity, Trifling Thermal and Concentration Quenching for Hybrid White LEDs and Li3Y3BaSr(MoO4)8:Sm3+, Eu3+-Based Deep-Red LEDs for Plant Growth Applications.

Trivalent europium-based monochromatic red light-emitting phosphors are an essential component to realize high-performance smart lighting devices; however, the concentration and thermal quenching restrict their usage. Here, we report a series of efficient Eu3+-substituted Li3Y3BaSr(MoO4)8 red-emitting phosphors based on a stratified scheelite structure with negligible concentration and thermal quenching. All of the host and phosphor compositions crystallize in monoclinic crystal structure (space group C2/c). All of the phosphor compositions produce narrow-band red emission (FWHM ∼6 nm), which is highly apparent to the human eyes, and lead to exceptional chromatic saturation of the red spectral window. Concurrently, detailed investigations were carried out to comprehend the concentration and thermal quenching mechanism. Absolute quantum yields as high as 88.5% were obtained for Li3Y0.3Eu2.7BaSr(MoO4)8 phosphor with virtuous thermal stability (at 400 K, retaining 87% of its emission intensity). The light-emitting diodes were constructed by coupling Li3BaSrY0.3Eu2.7(MoO4)8 red phosphor with a near-UV LED chip (395 nm) operated at 20 mA forward bias, and the hybrid white LED (an organic yellow dye + red Li3Y3BaSr(MoO4)8:Eu3+ phosphor integrated with an NUV LED chip) showed a low CCT (6645 K), high CRI (83) values, and CIE values of x = 0.303; y = 0.368, which indicated that the synthesized phosphors can be a suitable red component for white LEDs. In addition, we have systematically investigated the Sm3+ and Sm3+, Eu3+ activation in Li3Y3BaSr(MoO4)8 to display the latent use of the system in plant growth applications and establish that the phosphor exhibits orange red emission with an intense deep-red emission (645 nm (4G5/2 → 6H9/2)). The phytochrome (Pr) absorption spectrum well matched the fabricated deep-red LED (by integrating a NUV LED + Li3Y3BaSr(MoO4)8:Sm3+ and Eu3+ phosphor) spectral lines.

(INVITED)KRbAl2B2O7: Eu2+: A new blue-emitting luminescent material with good thermal stability

Exploring new efficient phosphor for lighting has always been a worthwhile and necessary work. Herein, we develop a new blue-emitting luminescent material KRbAl2B2O7:Eu2+ through the solid-state method. Under n-UV excitation, this phosphor can emit blue light peaking at 450 nm with FWHM about 55 nm. It owns a broad excitation spectrum covering from 250 nm to 425 nm. Two luminescent centers were identified through the analysis of crystal structure and decay times. Furthermore, the phosphor shows high thermal stability and the emission intensity remains about 81% at 425 K of that at room temperature. The thermal quenching is mainly attributed to the increase of non-radiative transition and thermally activated phonon-assisted tunneling effect at high temperature. By employing as-prepared material as blue phosphor, the fabricated white LED device can emit white light with high CRI (Ra = 85.6) and low CCT (4236 K). These results illustrate that the possibility of KRbAl2B2O7 as a blue-emitting phosphor for practical application.

Efficient and ultra-thermally stable Eu3+ and Sm3+-activated narrow-band red/deep red-emitting phosphors and their versatile applications.

A succession of Eu3+-activated Na2Y4(WO4)7 (NYW) red phosphors were synthesised and their optical properties were studied in detail for white LED, latent fingerprint and plant growth applications. The phosphors crystallised in a tetragonal system with space group I41/a. The NYW:Eu3+ red phosphors demonstrated a line-like emission at 616 nm owing to electric dipole transition, and a systematic concentration-dependent PL study revealed that concentration quenching occurs at x = 1.8 with a color purity of 96.06%. The thermal stability and internal quantum efficiency of the phosphor were found to be ∼75.54% (at 423 K) and 88%, respectively. Furthermore, solid solution phosphors were synthesized to increase QE, which was found to be 91.27%. Specifically, the hybrid white LED exhibits warm white light with high CRI (80) and low CCT (5730 K) values, and these values are further improved (CRI-81, CCT-4274 K) when the WLED is fabricated using the most efficient solid solution phosphor Na2Y2.2Eu1.8(WO4)3(MoO4)4. The currently synthesized phosphors can be potential candidates for security applications. The selected phosphor compositions can be used for the detection of latent fingerprints. Besides, a succession of Eu3+ and Sm3+ co-doped phosphors were synthesized and their photophysical properties were studied systematically. The deep red LED was fabricated using the same and this could be a possible light source for plant growth usage.

Cenário das barragens de rejeito: conhecer para evitar novas catástrofes

Abstract Mining is one of the key sectors of the Brazilian economy. However, despite its importance, tailings production is still significant and constitutes one of the greatest problems in this sector. Moreover, dam failure events have marked the history of the mining sector. From this perspective, this study aimed to assess the current scenario of tailings dams based on information contained in the SIGBM database. First, the number of dams included in the PNSB, their risk categories, potential damage, level of emergency, and other factors were observed. Then, data analysis indicated that Minas Gerais is the state with the largest number of dams included in the PNSB, with high CRI and DPA, dam construction by the upstream method, and dams classified as emergency level 3, thus requiring extra attention and interventions in order to ensure their safety.

Site-selective and cooperative doping of Gd3Al5O12:Ce garnets for structural stabilization and warm WLED lighting of low CCT and high CRI.

Synergistic doping of the metastable Gd3Al5O12:Ce garnet with a Ca2+/Hf4+ pair and Sc3+ to form Gd2.97-xCaxHfxScyAl3O12:0.03Ce (x = 0.5-2.0, y = 0.0-1.5, x + y = 2.0) solid solution was conducted for the structural stabilization and photoluminescence manipulation. The site selection of Ca2+/Hf4+/Sc3+ dopants and the effects of doping on the crystal structure, local coordination, band structure and Ce3+ luminescence were revealed in detail with the results of XRD, Rietveld refinement, TEM, and UV-Vis/photoluminescence spectroscopy. A decrease in Ca2+/Hf4+ and an increase in the Sc3+ content were observed to shrink the lattice, widen the bandgap of the garnet host, red-shift the excitation/emission wavelength, broaden the emission band and shorten the fluorescence lifetime of Ce3+. The spectral changes were rationalized by considering the local coordination and crystal field splitting of the Ce3+ 5d energy level. Application of typical Gd0.97Ca2Hf2Al3O12:0.03Ce (x = 2.0, y = 0) cyan and Gd2.47Ca0.5Hf0.5Sc1.5Al3O12:0.03Ce (x = 0.5, y = 1.5) greenish-yellow phosphors in w-WLED lighting produced low correlated color temperatures of ∼3842 and 3514 K, high color rendering indices of ∼88 and 93 and favorable luminous efficacies of ∼32.9 and 14.7 lm/W under the excitation of 395 nm n-UV and 450 nm blue LED chips, respectively.

Perylene diimide derivative dispersed in LDH as a new efficient red-emitting phosphor for LED applications

Substituted perylene diimide fluorophore exhibiting the ACQ effect in solid state becomes a strong red-emitting phosphor when confined into an LDH host. When combined with YAG : Ce, it enables producing warm white light with high CRI.

Effect of dental headlights spectrum on the polymerization and working time of light-cured resin composites.

BackgroundThe use of dental headlights is a common practice to better illuminate the operatory field and achieve excellence in restorative dentistry. However, visible light-cured dental materials can have reduced working time under headlight illumination. The aim of this study was to evaluate the influence of the spectral irradiance power of two dental headlights on the degree of polymerization and working time of light-curable dental composites. Material and MethodsTwo headlights, StarLight Nano 3 (StarMed) (SN) and Zeon Endevour XL (Orascoptic) (ZE) were characterized using a spectrophotometer coupled to an integrating sphere (MARC® Light Collector, BlueLight Analytics). The degree of conversion of the two composites, Filtek Supreme (3M) and Tetric Prime (Ivoclar Vivadent), was evaluated using an FTIR spectroscope (NicoletTM iS20, Thermo Fisher). ResultsBoth headlights emitted a significant amount of blue light. The Zeon headlamp without filter emitted a broader spectrum with lower blue intensity and higher CRI than the White LED of the Nano 3. The Zeon headlamp with the blue blocking filter emitted a broader spectrum than the Orange LED of the Nano 3. There were no differences in the degree of conversion and working time of the Filtek Supreme and Tetric Prime composites when illuminated by the different headlamps. Both Zeon and the White LED of the Nano 3 were capable to cure the composites within only 5-10 minutes of irradiation. There were no changes in the degree of conversion of the composites when the Orange LED of the Nano 3 or the blue blocking filter of the Zeon were used. ConclusionsBoth headlights reduced the working time of light-cured materials. The use of orange filters prevented the composite polymerization and maintained the working time. Key words:Surgical Headlight, degree of conversion, working time, light-curing.

Multichannel charge transfer enhanced radiative decay and RISC in TADF materials containing multiple donors and acceptors

Multichannel through-bond charge transfer and through-space charge transfer are realized in a TADF emitter D-tCz-D-BP, which enhance both radiation and RISC processes and lead to high EQEs of 24.9% in sky-blue OLED and 20% in a white OLED with high CRI of 80.

Atherogenic Index Profile on Ischemic Stroke Patients at Neurology Department, Dr. Soetomo Surabaya: A Retrospective Study

Stroke was associated with morbidity and mortality in the world. Lipid index discovered through lipid profile tests may be used as a predictor in vascular diseases. To increase the prediction value of lipid profile to stroke outcome, several lipoprotein ratios, called atherogenic index, were still being researched. Atherogenic indexes included Atherogenic index of plasma, Castelli Risk Index I and II, atherogenic coefficient, and non-high density lipoprotein cholesterol. The aim of this study is to find atherogenic index profile as a marker for atherogenicity on acute ischemic stroke patients at Neurology Department Dr. Soetomo hospital from January-September 2019. This is a retrospective descriptive of 65 patients on stroke registry. Data collected including low and high AIP level on 19, 46 patients, respectively; low CRI I on 22 patients and high CRI I on 43 patients; low CRI II from 31 patients and high CRI II from 34 patients; low and high AC on 9 and 56 patients, respectively; also, low NHC on 21 patients and high NHC on 44 patients. Poor outcome on outpatient was identified in 30 patients (NIHSS >7). This study indicates most ischemic stroke patients have high atherogenic index level. Analysis on the differences between lipid index and NIHSS poor outcome revealed AC and NHC level were significant with p = 0,031, CI 8,593 (1,007 – 73,319) and p = 0,01, CI 9,529 (2,435 – 37,3), respectively. Keywords: atherogenic index, ischemic stroke, NIHSS.

Blue-light-excitable broadband yellow-emitting CaGd2HfSc(AlO4)3:Ce3+ garnet phosphors for white light-emitting diode devices with improved color rendering index

The current commercial white light-emitting diodes (LEDs) are generally based on the combination of blue LED chips and Y3Al5O12:Ce3+ yellow phosphors. However, because of the lack of red component, such white LED devices exhibit cool white-light emissions with low color rendering index (Ra < 75, R9 < 0). Therefore, it is urgent to discover new blue-light-excitable yellow-emitting phosphors with enhanced red emissions for fabricating high color-quality white LEDs. In the present work, we demonstrate a novel broadband yellow-emitting CaGd2HfScAl3O12:Ce3+ garnet phosphor for blue-light-excited white LEDs with improved color rendering index. The as-prepared CaGd2HfScAl3O12:Ce3+ garnet phosphor possesses a cubic structure with Ia3¯d space group, and the unit cell parameters of the representative CaGd2HfScAl3O12:2%Ce3+ phosphor are a = b = c = 12.450 Å, α = β = γ = 90°, and V = 1,929.59(4) Å3. Impressively, we find that the CaGd2HfScAl3O12:Ce3+ garnet phosphor shows an intense absorption band in the 300–500 nm wavelength range with a maximum at 452 nm owing to the 4f→5d transition of Ce3+ ions. On 452 nm excitation, the optimal CaGd2HfScAl3O12:2%Ce3+ sample exhibits a broad asymmetric yellow emission band in the wavelength range of 470–750 nm with peak at 564 nm and full width at half maximum of 151 nm. The Commission Internationale de l’Eclairage chromaticity coordinates and internal quantum efficiency of the CaGd2HfScAl3O12:2%Ce3+ sample are (0.4485, 0.5157) and 30.4%, respectively. Finally, a white LED device is fabricated by combing a 450 nm blue LED chip with commercial Y3Al5O12:Ce3+ yellow-emitting phosphor, which generates white light with low color rendering index (CRI; Ra = 74.7, R9 = −12.7) and high correlated color temperature (CCT = 6,554 K) under the 60 mA driving current. In sharp contrast, another white LED device, which is made by coating our as-prepared CaGd2HfScAl3O12:2%Ce3+ yellow-emitting phosphors onto the surface of a 450 nm blue LED chip, produces white-light emission with high CRI value (Ra = 84.5, R9 = 26.3) and relatively low CCT of 5,649 K. This work reveals that the newly discovered broadband yellow-emitting CaGd2HfScAl3O12:Ce3+ phosphors can serve as a potential color converter in high-color-quality phosphor-converted white LEDs.

Enhanced self-host blue emission of CaSrSb2O7 materials via Bi3+ ion doping for high CRI WLEDs, security inks and flexible displays

Luminescent materials are indispensable in our daily lives and have already been widely applied in various fields. Herein, novel self-host blue-emitting CaSrSb2O7 and CaSrSb2O7:Bi3+ phosphors with orthorhombic space group Imma (74) were successfully prepared. The phase purity, elemental composition, morphology, luminescent behaviors, etc. were investigated in detail. To compare the luminescence properties of rare-earth-activated phosphors, the self-host blue-emitting CaSrSb2O7 phosphor with unique performance exhibited a good quantum yield (QY) of 39.81%, and its emission intensity and QY could also be improved by doping Bi3+ ions. The CaSrSb2O7:Bi3+ phosphor was located in the pure blue region with the Commission Internationale de I'Eclairage chromaticity coordinate of (0.151, 0.058) and good color purity of 89.35%. For identifying its potential applications, the packaged white light-emitting diode device emitted a high color rendering index value of 93.66 under a forward current of 300 mA, and it would be further applied in security inks and flexible displays owing to its strong emission by the naked eyes. These results suggest that novel self-host blue-emitting CaSrSb2O7:Bi3+ phosphors could be used in multifunctional applications.

Phosphor in glass composited with CsPb(BrI)3 perovskite nanocrystals embedded glass for high CRI WLED application

Here, YAG phosphor in tellurite glass composited with CsPb(BrI)3 nanocrystals embedded borosilicate glass have been successfully synthesized by Two-step melting method. The phase and morphology characterization proved that YAG and CsPb(BrI)3 nanocrystals existed in the prepared composite glass. The photoluminescence properties and color characteristics could be easily controlled by adjusting the mixing ratio of phosphor and quantum dot powder. In addition, by combining the phosphor and perovskite quantum dot glass composite material with a blue light-emitting diode, a white light-emitting diode (wLED) was successfully prepared. After a series of adjustments, the chromaticity coordinates (CIE) of the optimized high-performance wLED is (0.3376, 0.3531), the correlated color temperature (CCT) is 5299 K, and the color rendering index (Ra) is up to 86, which higher than that of the wLED packaged by single phosphor glass.