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Mn‐doped CsPbCl3 perovskite nanocrystal (PeNC) glass was prepared by melt quenching and in situ crystallization. Under the protection of robust glass, PeNCs exhibit excellent moisture resistance and thermal stability. The combination effect of thermal quenching and energy transfer of exciton to Mn2+ enables its promising applications in the field of temperature sensor. Interestingly, by matching with ultraviolet chips, all‐inorganic blue‐red emitting conversion device consisting of PeNC glass was prepared for light‐emitting diodes (LEDs), which can meet the light requirements of plant growth. The cultivation results indicated that the growth of cabbages using PeNC plant cultivation LEDs was greater than those cultivated using commercial w‐LEDs (white light‐emitting diodes). Therefore, Mn‐doped CsPbCl3 PeNCs can be used as a new generation of solid fluorescent materials in the field of indoor plant cultivation LEDs. [ABSTRACT FROM AUTHOR]

Currently, high optical purity, perfect stability, and high photoluminescence quantum yield (PLQY) are very important, being the key to obtain high‐quality luminescent materials. The research of perovskite nanocrystals (NCs) as optical materials is in full swing. Nevertheless, the low PLQY value, especially for the red‐emitting perovskite NCs, is a main obstacle to applications in display. This work reports the optimized components to synthesize CsPb(Br/I)3 NCs glasses whose PLQY achieves a big boost from 15.4% to ≈60% for the first time. Furthermore, the specimens exhibit exceptional tolerance to water and thermal and hence contribute to applicability in high‐performance light‐emitting diode (LED) and 3D printing. By combining CsPb(Br/I)3 NCs glass powder and yttrium aluminum garnet (YAG):Ce phosphor with blue chips, the assembled white LEDs reach a high luminous efficiency at 113.0 lm W−1. The resulting high PLQY is to the benefit of a substantial step toward the practical application of inorganic perovskite materials in the fields of optoelectronic devices and additive manufacturing. [ABSTRACT FROM AUTHOR]

A novel red‐emitting phosphor Ca5Ga6O14:Eu3+ has been synthesized using solid‐state method. The excitation and emission spectra show that the phosphor can emit the red light with the main peak at 611 nm under excitation of the 280 and 393 nm UV chip and the optimal Eu3+ concentration is determined to be x = 0.07. Analysis of emission spectrum shows that Eu3+ occupy the center of noninversion symmetry. With the increase of Eu3+ doping concentration, the decay time is prolonged due to deeper energy trap arising from nonequivalent substitution. Additionally, the measured thermal stability with 0.539 eV activation energy and calculated 90.5% color purity of optimal phosphor indicate that the phosphor has an enormous application potential in w‐LEDs industry. [ABSTRACT FROM AUTHOR]

In recent years, numerous efforts have been made to develop single-phased white light-emitting phosphors for the near-UV region to solve problems of color reabsorption and ratio regulation between different phosphors. In this work, we have designed Bi3+- and Eu3+-codoped single-phased Gd2MgTiO6 phosphors to achieve tunable white light emission based on multi-luminescence center energy transfer. The structural analysis showed that all the samples were crystallized as a monoclinic double perovskite with the P21/n symmetry space group (No. 14), with HRTEM images showing clear lattice fringes between the lattice planes. The single Bi3+-doped Gd2MgTiO6 sample exhibits two obvious emission peaks at 417 and 508 nm, which correspond to a characteristic 3P1 → 1S0 transition for the Bi3+ ions under near-UV excitation due to two types of Bi3+ emission centers, with their relative emission intensity depending closely on the value of the excitation wavelength. In this case, a suitable choice of excitation wavelength can achieve tunable emission for Gd2MgTiO6: Bi3+ between blue and green. Eu3+ is codoped into Gd2MgTiO6 as a red emission component and shows sharp emission lines that correspond to the characteristic 5D0 → 7FJ (J = 1, 2, 3, and 4) transitions of Eu3+ ions. Energy transfer in Gd2MgTiO6: Bi3+, Eu3+ has been confirmed by the electric dipole-dipole (d-d) interaction from Bi3+ to Eu3+. Our experiments show that it is straightforward to create tunable white light emission by adjusting the excitation scheme and Eu3+ concentration. Moreover, a schematic for the energy transfer mechanism and simplified spectral levels based on Bi3+ and Eu3+ ions has also been established. [ABSTRACT FROM AUTHOR]

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 2Eg → 2A2 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. [ABSTRACT FROM AUTHOR]

Various luminescent carbon materials are artificially synthesized and as admirable fluorescent materials because of the increased research of carbon nanodots (CDs). Herein, a novel solvent-dependent red CDs (rCDs) is introduced through solvothermal method. The as-prepared rCDs remain benzene structure and possess abundant surface function groups that endow them well solubility in various solvents. Furthermore, multicolor luminescence are observed when rCDs are dissolved in different solvents, and the emission wavelength of these materials can be well-tuned from 475 to 624 nm, which presents intensity solvent-dependent properties. Red luminescence carbon phosphors are successfully synthesized by mix rCDs with silica powder. Finally, warm white light emitting diodes (WLEDs) are constructed using rCDs powder with Ce3+: YAG single crystal and blue GaN chips. The results demonstrate that the rCDs can act as red component to modify the correlated color temperature (CCT) and the color rendering index (CRI) of WLEDs. [ABSTRACT FROM AUTHOR]

Eu3+ ions were introduced into the lattices of CsPbBr3 perovskite QDs and a tunable multicolour emission from CsPbBr3:xEu3+ perovskite QD glass was successfully obtained. Multicolour LEDs that were fabricated by combining the as-prepared CsPbBr3:xEu3+ QD glasses with a UV chip were also researched in this study. [ABSTRACT FROM AUTHOR]

Currently, phosphor-in-glass (PiG) approach draws great attention because of its excellent thermal resistance and facile process in WLED fabrication. However, the red light deficiency results in high correlated color temperature (CCT) and low color rendering index (CRI) in white light-emitting diode (WLED). Herein, a new LuAG:Ce 3+ phosphor-in-glass (Lu-PiG) combining with the CaAlSiN 3 :Eu 2+ red phosphor layer was synthesized by the low temperature co-sintering and screen-printing techniques, which was experimentally demonstrated to replace the conventional polymer-based phosphor converter and realized the chromaticity tuning for LuAG:Ce 3+ phosphor with WLED. The Lu-PiG constructed WLED exhibited excellent thermal stability, but it still showed a typical cold white light resulting from the absence of red light component. Therefore, a stacking geometric configuration by screen-printing a red phosphor layer on the Lu-PiG substrate (R&Lu-PiG) was designed to solve red deficiency problem. The R&Lu-PiG color converter showed an excellent thermal stability with only 8.2% emission loss compared to the Lu-PiG when elevating temperature from 303 K to 433 K. By adjusting the CaAlSiN 3 :Eu 2+ phosphor content in the layer, we obtained a high-performance warm WLED with a luminous efficacy of 102.1 lm/W, a CCT of 3410 K and a CRI of 76.5 under 20 mA current driving. Thus, it is expected that this developed R&Lu-PiG color converters could have large potential applications in high-power warm WLED. [ABSTRACT FROM AUTHOR]

Currently, phosphor-in-glass (PiG) approach draws great attention because of its excellent thermal resistance and facile process in w-LED fabrication. However, the absence of red emissive component results in poor chromaticity quality, which greatly restricts its application in the high-quality indoor lighting. In the present work, a transparent garnet-based PiG was successfully prepared by introducing the Y 3 Al 4.5 Ga 0.5 O 12 :Ce 3+ (YAGG) green phosphor into TeO 2 -based glass matrix, and we demonstrated the possibility offered by the screen-printing technique for warm w-LED applications by coupling the PiG plate stacked with a red phosphor coating on commercial InGaN LED. The microstructures and luminescent properties of them were investigated in detail. After simply varying the red phosphor concentration as well as the YAGG PiG thickness, a facile chromaticity tuning for the thus-fabricated LED was achieved in the range changing from cool white to warm white. Moreover, this developed luminescent material presented an excellent heat-resistance performance. Hopefully, the red phosphor coated PiG color converter is applicable in the long-lifetime high-power color-tunable w-LEDs. [ABSTRACT FROM AUTHOR]

A pivotal step in providing a better fluorescent material that has high luminous efficacy and excellent thermal stability is to utilize inexpensive phosphors for white light-emitting diodes (W-LEDs). Herein, we demonstrate a feasible tape-casting technique for creating phosphor thick films that consist of Ce: YAG phosphor embedded in relatively low melting point glass frits on an ultrathin glass substrate with controllable film thickness. The glass matrix has ideal densification and interfaces with the glass substrate at a relatively low temperature of 580 °C. Subsequently, the structure and optical properties of the phosphor layer are investigated. In addition, the effect of the phosphor concentration, thick film thickness and location (top or bottom) of the phosphor layer on the photoluminescence properties and chromaticity are also discussed with respect to use in W-LEDs. Significantly, this promising structure has excellent thermal stability and the potential to overcome current limitations of phosphors in high-power W-LEDs. Finally, a high-performance W-LED based on the planar phosphor glass exhibits a luminous efficiency of 108.45 lm W −1 , a correlated color temperature of 5408 K and a color rendering index of 76. [ABSTRACT FROM AUTHOR]

In this work, a novel environmentally friendly strategy toward phosphor-converted WLED employing Ce:YAG-doped glass via single-step low-temperature co-sintering technology was successfully synthesized, using low-cost PbO–B 2 O 3 –SiO 2 –ZnO glass as host, which showed good sintering behavior and high visible transparency under the sintering condition of 750 °C without noticeable interaction with phosphors. By simply changing thermal condition, phosphor doped concentration and specimen thickness for the viscous sintering of phosphor in glass (PiG), optical characterization of WLED can be easily tuned. As a result, it can be found that the ideal thermal condition is sintered at 700 °C for 40 min, the optimal amount of phosphor powder is controlled to be 5 wt% of the final mixture, and the best suitable thickness of specimens is 0.8 mm. The constructed PiG based WLED exhibits a high luminous efficiency of 134.33 lm/W, and a correlated color temperature of 4696 K as well as a color rendering index of 68.5. Enhanced thermal quenching property of PiG compared to phosphor with conventional silicone resin reveals the prominent feasibility of the present glass ceramic material in WLED application. [ABSTRACT FROM AUTHOR]

This study outlines a general but convenient approach towards the synthesis of a Ce3+:Y3Al5O12 phosphor-in-glass (PiG) with a relatively low sintering temperature. A comparative study of the as-synthesized PiG and glass ceramic prepared using a conventional route was carried out to explore the structural, morphological and optical properties. In addition, the effect of phosphor concentration and the sintering temperature/time on the luminescence properties was systematically investigated. Notably, we fabricated a high-performance white LED based on PiG with a high luminous efficacy (125 lm W−1), low correlated colour temperature (4329 K) and colour rendering index of 68. Furthermore, the PiG material demonstrates an excellent thermal stability up to 150 °C, superior to the low thermal stability of conventional Ce3+:Y3Al5O12 doped silicone. Therefore, we present a transparent phosphor glass with desirable potential for application in high powered W-LEDs. [ABSTRACT FROM AUTHOR]

• Low toxicity Ca2+ was successfully incorporated into CsPbBr 3 and CsPbBr 1 I 2 NCs. • The PLQY of 40% Ca2+-CsPbBr 3 and 40% Ca2+-CsPbBr 1 I 2 NCs can reach 72.3% and 78.7%. • Ca2+ doping inhibits the non-radiative recombination rate of NCs. • Ca2+ doped NCs encapsulated in superhydrophobic aerogels have excellent stability. • The red-emitting CCPBI@AG-4 makes the CRI of the WLED as high as 92.2. All-inorganic halide perovskite nanocrystals (NCs) have become the most promising next generation luminescent materials due to their excellent properties. However, there are many nonradiative recombination defects in colloidal perovskite NCs, which reduce their luminescent efficiency and stability. In this work, we incorporated the alkaline-earth (AE) metal ion Ca2+ into NCs to further improve the photoluminescence quantum yield (PLQY) of CsPbBr 3 and CsPbBr 1 I 2 NCs. The PLQY of green-emitting CsPbBr 3 and red-emitting CsPbBr 1 I 2 NCs can be boosted to 72.3% and 78.7%, respectively by doping the optimum amount of Ca2+. At the same time, we adopted a simple and low-cost one-pot method to integrate Ca2+-CsPbX 3 (X 3 = Br 3 , Br 1 I 2) NCs and superhydrophobic silica aerogels (AG), not only retaining the high PLQY of NCs, but also greatly improving the water, heat and light stability. Finally, the green-emitting Ca2+-CsPbBr 3 @AG, red-emitting Ca2+-CsPbBr 1 I 2 @AG composites and the blue chip as the light sources show a wide color gamut that accounts for 129% of the NTCS 1953 value and nearly 100% of the Rec.2020 value. Additionally, we fabricated white light-emitting diode (WLED) devices by coupling Ca2+-CsPbBr 1 I 2 @AG composites with commercial YAG:Ce3+ phosphors on blue chips, obtaining bright white light with a color rendering index (CRI) up to 92.2. [ABSTRACT FROM AUTHOR]

It is an important challenge to select suitable color converters and apply them to laser diodes (LDs) lighting field. Sapphire plates are used as substrates for phosphor-in-glass films (PiFs) due to their ultrahigh thermal conductivity (∼ 30 W m−1 K−1). Herein, Y 3 Al 3.5 Ga 1.5 O 12 :Ce3+ (YAGG:Ce) phosphor mixing silicate glass powder is successfully sintered on sapphire plates to fabricate YAGG:Ce phosphor-in-glass film (PiF). The microstructure appearance and photoelectric characteristics of the efficient green color converter are studied in detail. In addition, it is worth noting that the maximum internal quantum efficiency of the prepared PiF is 92%, which is close to that of the original phosphor (98%). Meanwhile, the saturation threshold of YAGG:Ce PiF reaches 38.96 W/mm2 with luminous efficiency (LE) of 230.85 lm/W under the excitation of 460 nm blue LD. Notably, PiF has ultra-high power density while still maintaining such high LE. In order to highlight the application of this color converter in laser lighting, we assemble laser flashlights and fireflies lights. The test of the laser flashlight shows excellent performances such as high brightness, strong focusing effect and wide irradiation range. All indications manifest that YAGG:Ce PiF is an excellent green color converter. [ABSTRACT FROM AUTHOR]

To cope with the market competition of solid-state lighting, there is an urgent need for an efficient and stable fluorescent conversion material that can be used in high-performance lighting. A novel and unique nitride phosphor, La 3 Si 6 N 11 :Ce3+ (LSN), exhibits a wider luminescence spectrum and better thermal quenching performance than Y 3 Al 5 O 12 :Ce3+ (YAG). In this study, LSN phosphors are dispersed in a SiO 2 –B 2 O 3 –CaO–Na 2 O glass system, and a series of LSN phosphor-in-glass (LSN PiG) samples are prepared by a low-temperature co-sintering technique. The luminescence, thermal stability, microstructure and photoluminescence properties are investigated. The internal quantum efficiency of LSN:Ce PiG (85%) is close to that of the original phosphor (90%). Under excitation of a 450 nm blue laser diode, the LSN PiG produces white light with a luminescence efficiency of 145.91 lm/W, and a luminous flux of 209lm is achieved. Moreover, the color rendering index of LSN is much higher than that of YAG, reaching 73, indicating that LSN PiGs have good application prospects as yellow converters in high-power laser lighting. [ABSTRACT FROM AUTHOR]

Currently, the major commercial white light-emitting diode is the phosphor converted LED made of blue-emitting chip and Y 3 Al 5 O 12 :Ce 3+ yellow phosphor dispersed in organic silicone. However, the organic binder in high-power device ages easily and turns yellow due to accumulated heat emitted from chip, which adversely affects the device properties such as luminous efficacy and color coordination, and therefore reduces its long-term reliability as well as lifetime. In this mini-review article, we provide an overview of recent progresses in developing transparent inorganic glass–ceramics phosphors excitable by blue chip, as an alternative to conventional polymer-based phosphor converter, for construction of high-power white light-emitting diodes. Two kinds of synthesis routes, glass crystallization and low-temperature co-sintering, are discussed in detail. Afterwards, the materials design, structure/property optimization as well as glass–ceramic-based WLED devices construction are summarized. Finally, challenges and future advances for the realization of transparent glass–ceramics in commercial applications will be presented. [ABSTRACT FROM AUTHOR]

Stable color converters exhibiting high color rendering index have drawn researchers' attention for their applications in high-quality white laser lighting. In this study, we develop the multi-color phosphor-in-glass (PIG) with the weight ratio of green-emitting (Y 3 Al 3.08 Ga 1.92 O 12 :Ce3+) to red-emitting (CaAlSiN 3 :Eu2+) phosphor powders (10/1–18/1) by low temperature co-sintering method. The obtained composite material displays an outstanding optical and thermal performance, including a high internal quantum efficiency of 84.2%, a high transparency of 45% in the visible region and a low thermal quenching (it remains 86% at 448 K). By integrating 450 nm blue laser diodes with optimized multi-color PIG, the white light with a maximum luminous flux of 258 lm and a luminous efficiency of 137 lm/W is achieved for the first time. Additionally, considering the white balance, by tailoring the weight ratio of green-emitting to red-emitting phosphor and the thickness of PIG, the 14/1 PIG at fixed thickness of 0.75 mm produces pure white light with ultra-high color rendering index of 95.2 and a high luminous efficiency of 120.9 lm/W under power density of 2.39 W/mm2 irradiation. The above superior characteristics imply that the multi-color PIG is an ideal candidate for high-quality white laser lighting applications. [ABSTRACT FROM AUTHOR]

Since being synthesized, CsPbX 3 (X = Cl, Br or I) quantum dots (QDs) have gained increased interest due to their superior performances in photovoltaic applications. Herein, Sm3+-doped CsPbBr 3 nanocrystallines (NCs) were successfully prepared in zinc borosilicate sodium (ZnO–B 2 O 3 –SiO 2 –Na 2 CO 3 , ZBSN) glass, and the as-prepared glass exhibited a strong red emission, which was attributed to the effects of the energy level transitions in Sm3+. Importantly, white light-emitting diodes (W-LEDs) were prepared by combining the glass with a blue InGaN chip, eliminating the need for a red phosphor to provide the red light, and white light was generated with a high colour rendering index (CRI: 82.6), a low correlated colour temperature (CCT: 4455 K) and colour coordinates in the white light region (0.3547, 0.3234). The glasses show excellent stability at 85 °C and 85% RH. Therefore, the Sm3+-doped CsPbBr 3 NCs glass can be used as a colour converter for application in lighting engineering. [ABSTRACT FROM AUTHOR]

Inorganic perovskite nanocrystals (NCs) doped with metal ions have received much attention due to their superior optoelectronic properties and environment friendly. Here, we synthesized Zn-doped CsPbBr 3 perovskite NCs in borosilicate glass by melt-quenching. When ZnBr 2 and PbBr 2 were in half, the fluorescence intensity was enhanced, and the PLQYs increased from 32 to 36%. Under the excitation of 460 nm blue chip, white LED (WLED) was fabricated by using Zn-doped CsPbBr 3 NCs glass and red phosphor powder CaAlSiN 3 :Eu2+. The experimental results show that the photoelectric parameters of the constructed white LED are considerable, among which the luminous efficacy (LE) is 70.1 lm/W, and a high LE is 72.79. However, pure CsPbBr 3 has a low LE value of 26.1 lm/W and a CRI value of 76.9 Zn2+ doped CsPbBr 3 can reduce the toxicity of materials and can be used to prepare high-performance optical devices. The study showed a new doped chemical model system for various optoelectronic applications. [ABSTRACT FROM AUTHOR]

Transparent red-emitting Cr-doped Y 3 Al 5 O 12 (Cr3+:YAG) single crystal (SC) was grown by the Czochralski method. Compared with commercial red phosphors, Cr3+:YAG single crystal wafers (SCWs) display excellent thermal stability and high Internal quantum efficiency (IQE) of 92%. Ulteriorly, we obtained a high-performance Ce:YAG/Cr3+:YAG SCWs-based W-LED operated at 20 mA with a CRI of 76.4, a CCT of 5236 K, a LE of 118.36 lm/W. More importantly, the white light stability of such device under 200 mA current driving was also investigated in detail. The results all provide strong support for the high power W-LEDs illumination application. Ce:YAG/Cr3+:YAG SCWs-based W-LEDs have potential applications for the high power W-LEDs illumination application. Image 1 • Transparent red-emitting Cr3+:YAG SC grown by the Czochralski method have been applied for W-LEDs. • Compared with commercial red phosphors, Cr3+:YAG SCWs display excellent thermal stability and high IQE of 92%. • A lower light loss of Cr3+:YAG SC under a high temperature (in the temperature 378 K and 438 K). • The Ce:YAG/Cr3+:YAG SCWs-based W-LEDs shows good white light stability when high current density is applied. [ABSTRACT FROM AUTHOR]

Abstract In recent times, white-light emitting diodes (W-LEDs) have been widely used as light sources. However, most of the commercial lamps lack the red-light component. Herein, study on a novel blue-light activated alkaline earth ion doped Mn4+:Y 3 Al 5 O 12 (Mn4+:YAG) phosphor, exhibiting a strong red emission that is attributed to the Mn4+: 2E g →4A 2g spin-forbidden transition in the 650–750 nm spectral region, that can be excited by both near-ultraviolet and blue chips is presented. The dopants Be2+, Mg2+, Sr2+, and Ba2+ were found to be significantly beneficial for enhancing Mn4+ luminescence, the related mechanism is systematically discussed here. In addition, the concentration quenching is systematically investigated. The crystal field strength (Dq) and the Racah parameters (B and C) are carefully calculated. After incorporating Mn4+/Be2+:YAG phosphors (glass ceramics) and GaAG phosphors into a blue LED device, white light with a high color rendering index and a low correlated color temperature is successfully obtained. Therefore, the Mn4+/Be2+:YAG phosphor can serve as color converter for application in W-LED. Highlights • Luminescence of Mn4+YAG red phosphor was enhanced via alkali earth ion doping. • Mn4+/Be2+YAG GC was prepared via low temperature co-sintering technique. • Mn4+/Be2+YAG phosphors and GaAG phosphors into a blue LED device. [ABSTRACT FROM AUTHOR]

To achieve efficient phosphors that address the shortage of red emission for use in white light emitting diodes (WLED), a series of red-emitting phosphors of Sr 2 MgGe 2 O 7 doped with different concentrations of Mn 4+ have been successfully fabricated by a high-temperature solid-state method. The crystal structure properties including the phase purity were analysed by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Absolute quantum yield, temperature stability, and lifetime were utilized to characterize the samples. Furthermore, the excitation spectra of the samples exhibit two broad absorption bands with peaks located at approximately 308 nm and 419 nm, which could be excited by near-UV/blue LED light. The emission spectra range from 600 nm to 700 nm and exhibited a sharp peak at 659 nm due to the 4 E→ 4 A 2 spin- and parity-forbidden transition of Mn 4+ . The optimal Mn 4+ doping concentration in the Sr 2 MgGe 2 O 7 host is determined to be 0.7%. The critical energy transfer distance of these phosphors is calculated to be about 26.61 Å, and the concentration quenching mechanism is proved to correspond to a dipole-dipole interaction. The luminescence of the Sr 2 MgGe 2 O 7 :Mn 4+ phosphors decrease gradually with increasing temperature, and the Sr 2 MgGe 2 O 7 :Mn 4+ sample exhibits better thermal stability than the commercial Sr 2 Si 5 N 8 :Eu 2+ red phosphors. The warm WLED is fabricated by combining the Sr 2 MgGe 2 O 7 :0.7%Mn 4+ and YAG:Ce 3+ phosphor with a 420-nm blue LED chip to explore its possible applications in warm WLED. [ABSTRACT FROM AUTHOR]

Currently, the exploration of non-rare-earth Mn 4+ -activated oxide red phosphor is of great demand for phosphor-converted warm white-light-emitting diodes (W-LEDs). Here, Mg 2 TiO 4 :Mn 4+ and Mg 2 TiO 4 :Mn 4+ ,Zn 2+ red phosphors were prepared using a solid-state reaction route and exhibited a strong red emission peaked at ∼657 nm. The microstructure and luminescent performance of the obtained red phosphors were investigated. Additionally, the concentration quenching and nephelauxetic effect of Mn 4+ in the Mg 2 TiO 4 host lattice were evaluated in detail. Moreover, Mg 2 TiO 4 :Mn 4+ ,Zn 2+ manifests an enhanced luminescence intensity compared to the sample without Zn 2+ doping with a quantum efficiency of 38.2% and good thermal resistance of Δ E = 0.36 eV. As proof of concept, when we incorporated Mg 2 TiO 4 :Mn 4+ ,Zn 2+ and commercial YAG:Ce 3+ into the package of a blue LED chip, a warm white light was produced with a high colour rendering index and a low correlated colour temperature; thus, they have promise as an application as a colour converter in the field of warm W-LEDs. [ABSTRACT FROM AUTHOR]

It is high-profile that the use of phosphor-in-glass (PiG) is extensive because of its excellent advantages in thermal resistance and lifetime aspects, and so on. Here, white light-emitting diodes (WLED) based on LuAG:Ce 3+ PiG coated red-emitting K 2 SiF 6 :Mn 4+ (KSF) phosphors by screen-printing are fabricated. Among all of these, the commercial LuAG phosphors and glass raw materials of TeO 2 -based glass, were weighted and milled in an agate thoroughly. Then, the mixture was melted and sintered at 850 K or so for 20 min in the ambient atmosphere through low temperature co-fired method, cold-forming LuAG PiG clump and cut into different LuAG PiG thicknesses. After that, the commercial red phosphor KSF was coated on LuAG PiG by screen-printing technique. Finally, high-performance WLEDs based on the TeO 2 -based glass were obtained, tested and characterized, which exhibit a highest color rendering index of 94.1, a lowest color temperature of 3744 K and a largest luminous efficiency of 101.02 lm·W −1 . Most noticeably of all, the promising method has excellent developing potential for industrialization in high-power WLED. [ABSTRACT FROM AUTHOR]

Currently, the non-rare-earth Mn 4+ -activated oxide red phosphor is of great interest as color converter for warm white light-emitting diodes (W-LEDs), owing to its admirable luminescent properties and low price. Herein, a novel blue-light activated Ca 14 Zn 6 Ga 10 O 35 :Mn 4+ (CZG:Mn 4+ ) phosphor, exhibiting strong red emission attributed to Mn 4+ : 2 E g → 4 A 2g spin-forbidden transition in region of 650–750 nm under 462 nm excitation, is successfully synthesized through a traditional solid-state reaction route in air. Subsequently, the microstructure and luminescent performance of this red-emitting phosphor are discussed in detail. The crystal field strength ( Dq ) and the Racah parameters ( B and C ) are carefully calculated to estimate the nephelauxetic effect of Mn 4+ suffering from the CZG host lattice. In addition, the concentration quenching and thermal quenching characteristics are also systematically investigated. After incorporating CZG:Mn 4+ and commercial Y 3 Al 5 O 12 :Ce 3+ (Ce:YAG) phosphors into a blue LED device, warm white light with high color rendering index and low correlated color temperature is successfully achieved. Therefore, the CZG:Mn 4+ phosphor can serve as color converter for use in warm W-LED applications. [ABSTRACT FROM AUTHOR]

In recent years, the success of laser lighting and display technology depends on the comprehensive properties of light conversion materials such as thermal stability and luminous efficiency. Therefore, fluorescent glass has become the main research object due to its outstanding comprehensive properties such as simple preparation and high quantum efficiency. In this study, a kind of Na 2 O-K 2 O-SrO-MgO-CaO-Al 2 O 3 -B 2 O 3 -SiO 2 glass matrix was carefully designed to reduce the damage of Y 3 Al 5 O 12 :Ce3+(Ce:YAG) phosphor in the compounding process. This glass component not only has a low melting point, but also has a high thermal conductivity. More importantly, Ce:YAG phosphor-in-glass (Ce:YAG-PiG) prepared by mixing the optimized glass powder with Ce:YAG phosphors has high thermal conductivity and luminescent properties. Under the excitation of 460 nm blue light, the quantum efficiency of Ce:YAG-PiG can reach 84.8%, which is 91.8% of that of the phosphors (92.4%). When the temperature is below 225 ℃, the thermal conductivity of the sample can be kept above 2.0 Wm−1K−1. Particularly, without any heat dissipation measures, the sample can withstand 3.15 W/mm2 blue laser radiation, and the luminous flux (LF) is 517.83 lm. The results show that this Ce:YAG-PiG composite material can be used for ultra-high brightness laser illumination, which will have a good application prospect. • High-performance Ce:YAG-PiG was synthesized by well-designed glass matrix and Ce: YAG phosphors. • The excellent IQE of Ce:YAG-PiG is as high as 84.8 %, which keeps good optical performance. • The optimized Ce:YAG-PiG keeps the thermal conductivity of 1.9 Wm−1k−1 at 275 ℃ without any heat dissipation measures. • Ce:YAG-PiG can withstand an incident power density of 3.15 W/mm2 and achieve an ultra-high luminous flux of 517.83 lm. [ABSTRACT FROM AUTHOR]

Transparent Ce 3+ and Gd 3+ co-doped Y 3 Al 5 O 12 (Ce,Gd:YAG) single crystal (SC) was successfully grown by the Czochralski method. Meanwhile, the structures and optical properties of single crystal wafers (SCWs) were investigated. When Y 3+ ions were partially substituted by Gd 3+ ions, the emission peak shifted towards the long wavelength direction. Compared with commercial phosphors, SCWs not only showed excellent thermal stability, but also exhibited superior optical performance with a luminous efficacy of 144.11 lm/W, a correlated color temperature of 5639 K and a color rendering index of 69.9. [ABSTRACT FROM AUTHOR]

In this paper, CsPbX 3 (X = Br, I) quantum dots glasses solid materials are fabricated based on the melting and heat-treatment methods. A series of characterization measurements are carried out to research the microscopic morphology and luminescent properties of solid materials. Finally, the multicolour light-emitting devices (LEDs) are constructed by adhesion commercial InGaN blue chip with as-prepared glasses. [ABSTRACT FROM AUTHOR]

The development of CASN (CaAlSiN 3 : 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. • A series of high-quality CASN-PiG films have been successfully prepared. • CASN-PiG film exhibit excellent EQE approaching 86% of original phosphors. • The luminous flux of the PiG film is reached 164 lm. • The CASN-PiG film has a higher thermal conductivity (12.935 W m−1 K−1). • The Ce:YAG&CASN-PiG film achieves a high luminous flux of 845 lm under 5.64 W/mm2 laser irradiation. [ABSTRACT FROM AUTHOR]

All-inorganic cesium lead halide perovskite quantum dots (QDs) have attracted widespread attention due to unique photoelectric properties. However, blue-emitting (CsPbCl x Br 3−x , 0 < x ≤ 3) QDs have poor stability and low photoluminescence quantum yields (PLQY), which limits its application in perovskite based light-emitting diodes (LEDs). The chlorine-free CsPbBr 3 QDs have fewer crystal defects and a more stable crystal structure. Here, we prepared CsPbBr 3 QDs with adjustable photoluminescence (PL) (489–519 nm) by controlling the reaction temperature and composited it with natural mineral halloysite (Hal) nanotubes. The as-prepared CsPbBr 3 @Hal (100 °C) have high PL intensity, bright blue emission and enhanced stability. Under an open ambient condition, the CsPbBr 3 @Hal (100 °C) can still maintain 92.4% of original PL intensity after 60 days of storage. In addition, after 280 h of continuous irradiation with 365 nm UV lamp, its PL intensity still maintained 71%. Finally, a white LED (WLED) fabricated by incorporating the CsPbBr 3 @Hal (100 °C) and commercial red CaAlSiN 3 : Eu2+ phosphor on the 395 nm InGaN blue-violet chip showed the CIE chromaticity coordinates of (0.3358, 0.3331). This work provides a new way for the synthesis and application of blue-emitting CsPbBr 3 perovskite materials in WLEDs and display devices. [Display omitted] • Samples prepared at different temperatures have high PL intensity and stability. • The CsPbBr 3 @HNTs (100 °C) has bright blue emission and perfect stability. • The WLEDs made by CsPbBr 3 @HNTs produce high quality white light and are adjustable. [ABSTRACT FROM AUTHOR]

• The prepared multi-color PiGs has a high internal quantum efficiency approaching 90% of original phosphors. • The luminous efficacy of YAG:Ce-PiG reaches 239.3 lm/W, which is almost the best result in WLDs so far. • Kinds of cyan/green/yellow/red phosphors can be composited into an entire PiG frame and full-color emissions from 470 to 700 nm is realized in WLDs. • The ideal white light with a high color rendering index of 94 is obtained in WLDs. Phosphor-in-glass (PiGs) is one of the most important strategies to overcome thermal influence in high-power white light-emitting diodes and laser diodes. By carefully designing the glass composition of Na 2 O-CaO-B 2 O 3 -SiO 2 , the multi-color PiGs are successfully fabricated by a single-step co-sintering strategy at a relative low temperature (850 °C), most of PiGs maintain a high internal quantum efficiency approaching 90% of original phosphors. Under the 450 nm blue laser diodes (LDs) excitation, the luminous efficacy of YAG:Ce-PiG reaches 239.3 lm/W, which is almost the best result in white laser diodes (WLDs) so far. Outstandingly, the designed glass overcomes the oxidation, corrosion and decomposition of commercial nitride red phosphors, and realizes broadband emission from 500 to 700 nm by compositing red/yellow/green phosphors in an entire glass. Correspondingly, this work paves the way to achieve ideal white light with a high color rendering index of 94 in WLDs. [ABSTRACT FROM AUTHOR]

• High quality CaAlSiN 3 :Eu2+ PiGs have been successfully synthesized. • CaAlSiN 3 :Eu2+ PiGs presented a higher EQE of 53% and better thermal stability. • The wLEDs with high CRI/LE were assembled successfully based on CaAlSiN 3 :Eu2+ PiGs. • The LDs based on CaAlSiN 3 :Eu2+ PiGs realized enhanced laser saturation threshold. CaAlSiN 3 :0.2%Eu2+ (CASN:Eu2+), an excellent red phosphor, plays a leading part in wide color gamut and high color rendition white light-emitting diodes (wLEDs). However, this phosphor or silicone resin mixture possesses a fatal defect of an intrinsic low thermal performance, which makes it hardly useful in high-power laser lighting and displays. Here, to improve the thermal performance of the CASN:Eu2+ phosphor, a series of red-emitting phosphor-in-glass materials (R-PiGs) with different CASN:Eu2+ concentrations (5–50 wt%) and sintering temperatures (750–850 °C) were successfully synthesized by dispersing the CASN:Eu2+ phosphor into a B 2 O 3 -Na 2 O-SiO 2 -CaO glass matrix. Surprisingly, the prepared R-PiGs showed a high external quantum efficiency (EQE) of 53%, and still maintained 82% efficiency compared with the CASN:Eu2+ phosphor (65%). The R-PiGs are superior to red ceramics for low cost and rapid batch preparation. Considering the densification of the R-PiGs, a systematic study was conducted on 10 wt% R-PiG sample. A facile chromaticity tuning for the configured wLEDs was obtained within the color range change from cool white to warm white when using the R-PiGs with different CASN:Eu2+ concentrations. Besides, we have successfully assembled a warm wLED with high luminous efficacy (90.3 lm/W) and color rendering (Ra = 94.2 and CCT = 5053 K). When irradiated by a blue laser, an optimized R-PiG can show enhanced luminous flux (49.27 lm) at a high laser incident power of 1.90 W/mm2. Therefore, with their excellent performances, R-PiGs are highly promising for use as red color converters for potential applications in tunable wLEDs and high-power laser lighting. [ABSTRACT FROM AUTHOR]

CsPbX 3 (X=Cl, Br or I) has been studied due to its outstanding optical properties. However, it is difficult to use in practical applications due to its poor stability. Currently, there are interesting examples of CsPbX 3 compounded with glass substrates. The quantum efficiencies of CsPbX 3 NC glasses are relatively low. In this work, we propose a simple method for fabricating Yb3+-doped CsPbI 3 quantum dots in glass via a conventional melt quenching technique. It was found that the CsPbI 3 NC glasses had blue-shifted emission with increasing amounts of the Yb3+ dopant. The photoluminescence quantum yield (PLQY) of CsPbI 3 : Yb3+ NC glass reached from 20% to 66.7%. And the CsPbI 3 : Yb3+ NC glass exhibited good thermal stability. Moreover, the experimental results showed th*at the CsPbI 3 : Yb3+ glass could match the properties of a commercial fluorescent powder used to make white LEDs (WLEDs). [ABSTRACT FROM AUTHOR]

Cd2+ doped CsPbBr 3 perovskite quantum dots were synthesized in borosilicate glass for the first time by traditional melting method. By X-Ray Diffraction (XRD) and high resolution electron microscopy analysis, it was proved that Cd2+ successfully entered the perovskite lattice structure. The samples have good optical properties, high photostability, chemical stability, thermal stability and water stability. On this basis, CsPb 0.7 Cd 0.3 Br 3 QDs glass, commercial red phosphor (CaAlSiN 3 :Eu2+) and blue light chip were coupled to produce white LED devices. This discovery opens up a new way for the application of metal ion-doped perovskite QDs glass in optoelectronic devices. • A series of Cd2+ doped CsPbBr 3 QDs glasses with high PL intensity, quantum efficiency and excellent stability were prepared. • The WLEDs made by CsPb x Cd 1-x Br 3 QDs glass produce high quality white light, adjustable from cold to warm white light. • Compared with the original CsPbBr 3 QDs glass, the quantum efficiency of Cd2+ doped glass has been improved greatly. [ABSTRACT FROM AUTHOR]

• Ti-doped CsPbI 3 QDs were successfully prepared in borosilicate glass matrix. • Ti-doped CsPbI 3 QDs@glasses possess superior optical performance. • The water/thermal stability of Ti-doped CsPbI 3 QDs@glasses are excellent. • The wLED based on CsPb 1− x Ti x I 3 QDs@glasses realized outstanding LE and CRI. • LED devices based on CsPb 1− x Ti x I 3 QDs@glasses well satisfy plant growth. Currently, the application of all-inorganic cesium lead halide perovskite (CsPbX 3 , X = Cl, Br, I) quantum dots (QDs) is limited due to toxicity of lead and poor ambient stability. In our work, a series of Ti-doped CsPbI 3 QDs were successfully prepared in borosilicate glass (SiO 2 -B 2 O 3 -ZnO) by the melt quenching and in situ crystallization technique. The samples showed excellent water/thermal stability, and the tunable emission (650–695 nm) was controlled by different Ti contents and heat treatment temperatures. In particular, the optical properties of CsPb 1− x Ti x I 3 QDs@glasses (x ≤ 0.5) are superior to those of pristine CsPbI 3 QDs@glass. As a result, the wLED was assembled using red-emitting CsPb 1− x Ti x I 3 QDs@glasses and yellow-emitting Ce3+:YAG phosphor under excitation of InGaN blue chip, which demonstrated an outstanding luminous efficiency of 102.44 lm/W, a high color rendering index of 80.6. Particularly, Ti-doped CsPbI 3 QDs@glasses with red and far-red light are combined with a blue-chip to assemble an LED device, which exactly satisfies the lighting conditions of plant growth. [ABSTRACT FROM AUTHOR]

• K x Cs 1−x PbBr 3 NCs glasses and KPbBr 3 NCs glass have been successfully synthesized. • K 0.6 Cs 0.4 PbBr 3 NCs glass presented a higher PLQY of 62% and better stability. • Optical third-order nonlinearity of K 0.6 Cs 0.4 PbBr 3 NCs glass was researched. • High-performance WLEDs was assembled successfully by K 0.6 Cs 0.4 PbBr 3 NCs glass. CsPbX 3 (X = Cl, Br, I) nanocrystals (NCs) glasses formed utilizing conventional melt-quenching with a subsequent heat-treatment method demonstrate excellent performance and can resist temperature and light irradiation; further, CsPbX 3 NCs glasses have improved stability in air and water when compared to traditional way. Nevertheless, one of the fatal disadvantages of CsPbX 3 NCs glasses are their low photoluminescence quantum yields (PLQY). Here, we demonstrate a new avenue that K+ ions doped CsPbBr 3 NCs glasses (K-CPB NCs glasses) systems utilizing K x Cs 1−x PbBr 3 (x = 0, 0.2, 0.4, 0.6, 0.8, 1) NCs glasses, and we surprisingly find that K 0.6 Cs 0.4 PbBr 3 NCs glass reaches the highest PLQY of 62% when the molar ratio of K+/Cs+ = 0.6/0.4. Meanwhile, in comparative experiments, we have noticed that K 0.6 Cs 0.4 PbBr 3 NCs glass has better water resistance and thermal stability than CsPbBr 3 NCs glasses what we had before. K-CPB NCs glasses has a significantly improved applications scope for cesium lead halide perovskite in the field of photoelectricity, such as solar cells and perovskite light-emitting diodes (PeLEDs). In addition, we have successfully fabricated the pure phase of KPbBr 3 NCs glass and its existence has been proven via a series of representational means, consequently, this research opens the door for the further study of perovskite materials. Fortunately, K-CPB NCs glasses perform better in optical third-order nonlinearity, and we believe these findings will promote its applications in nonlinear optoelectronic devices. Ultimately, white LEDs (WLEDs) has been successfully equipped with K 0.6 Cs 0.4 PbBr 3 NCs glass, which presents excellent optical parameters. [ABSTRACT FROM AUTHOR]