New red phosphor ceramic K2SiF6:Mn4+

Osborne, Ross; Cherepy, Nerine J.; Seeley, Zachary M.; Payne, Stephen A.; Drobshoff, A.; Srivastava, A.M.; Beers, W.W.; Cohen, W. W.; Schlagel, Deborah L.

doi:10.1016/j.optmat.2020.110140

Cited by 27 publications

(21 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As for the KSFM phosphor, when the laser power density is increased from 0.05 to 0.32 W mm À2 , the surface temperature merely rises from 27.7 to 65.5 C. However, the temperature rapidly reaches 258.3 C, when the laser power density is 0.63 W mm À2 , and the surface of the phosphor is badly burned down (Figure 7b). The sharp increase in temperature can be explained as follow: due to the long lifetime of the excited state and relatively low absorption cross section for Mn 4þ , [26] the absorption is easy to reach saturation under the irradiation of laser and more light will be reflected or scattered in the phosphor grains, which leads to an increase in temperature. Unfortunately, the low thermal conductivity of the phosphor plate cannot dissipate the heat effectively and cause the accumulation of heat.…”

Section: Thermal Quenching and Resistancementioning

confidence: 99%

“…[ 25 ] Recently, KSFM single crystal phosphor and transparent ceramics, with high luminescence efficiency and thermal stability, have been reported successively. [ 16,26 ] However, the complex fabrication process and high cost of single‐crystal phosphor and phosphor ceramic limit their mass production. Furthermore, the relatively low thermal conductivity of the KSFM ceramic (≈1.0 W m −1 K −1 ) and single crystal is not satisfied for high brightness applications.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Stable and Efficient Red‐Emitting Color Converter Based on K₂SiF₆:Mn⁴⁺ Phosphor‐in‐Glass Film for Next‐Generation Laser‐Excited Lighting and Display

Shi

Huang

Zhang

et al. 2021

Advanced Photonics Research

View full text Add to dashboard Cite

Laser diodes (LDs) are expected to be the next‐generation high luminance sources because of the unobvious “efficiency droop” phenomenon under high power. To achieve high‐quality white lighting, red emission is essential for white lighting devices. K2SiF6:Mn4+ (KSFM) is a highly suitable red phosphor for its strong broadband excitation in the UV and blue region and intense red emission at 631 nm. In addition, the ultranarrow emission makes it suitable for wide gamut displays. Herein, a stable and easily prepared red color converter, KSFM based phosphor‐in‐glass films on a coated sapphire substrate (CSA) is developed, which exhibits a high thermal conductivity of 32.02 W m−1 K−1. Compared with the KSFM phosphor, this KSFM–CSA composite shows an overall increase in thermal quenching and irradiation resistance abilities. A wide color gamut covering 128% of the National Television Standards Committee (NTSC) standard white LD (WLD) is fabricated by coupling a green‐emitting CsPbBr3 embedded glass plate and red‐emitting KSFM–CSA with blue LDs. Furthermore, a high‐quality WLD with a luminous flux (520 lm), luminous efficiency (93.0 lm W−1), and color rendering index (CRI, 81.4) is achieved. With its excellent properties, the KSFM–CSA has great potential in high‐power laser lighting and display.

show abstract

Section: Thermal Quenching and Resistancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Stable and Efficient Red‐Emitting Color Converter Based on K₂SiF₆:Mn⁴⁺ Phosphor‐in‐Glass Film for Next‐Generation Laser‐Excited Lighting and Display

Shi

Huang

Zhang

et al. 2021

Advanced Photonics Research

View full text Add to dashboard Cite

show abstract

“…Even though the droop performance is lower than the recently reported KSF ceramics. [ 34 ] However, the Mn 4+ ‐doped fluorides will not use alone in high‐power or LD devices, but with combination of YAG yellow phosphor or SiAlON green phosphor for white light‐emitting devices. The composition of white LD is designed as Figure 5d, and the assembled device photos are shown in Figures 5e,f.…”

Section: Resultsmentioning

confidence: 99%

Three Birds with One Stone: K₂SiF₆:Mn⁴⁺ Single Crystal Phosphors for High‐Power and Laser‐Driven Lighting

Zhou

Song

et al. 2020

Advanced Optical Materials

View full text Add to dashboard Cite

the broadband excitation in the blue region (≈450 nm) and efficient narrowband red emission at ≈630 nm, these phosphors are the ideal candidates as red components in LED backlight displays and warm WLEDs lighting. [5] However, these phosphors are always suffering from poor moisture resistance and lower external quantum efficiency (EQE). [6] Though the moisture resistance can be effectively improved by coating inorganic or organic layer, it inevitably increases the surface defects, which would eventually reduce the EQE, as well as affect the thermal stability and heat dissipation. [7] Generally, higher Mn 4+ concentrations lead to higher absorption and retain high EQE. [8] Moreover, Mn 4+ ions are exposed to the outside of the particle surface, which in turn leads to Mn 4+ hydrolysis. [9] Therefore, it is a fundamental challenge to realize the balance between the high EQE and excellent moisture resistance for Mn 4+-doped fluoride red phosphors. [6,10] Single crystal phosphor represented by YAG was regarded as a promising alternative to powder counterpart due to its high crystallization, fewer defects, and higher thermal conductivity. [11] Especially, the effective heat dissipation compared to powder phosphor in encapsulants, facilitates the dissipation of heat in the devices. [12] In this regard, high quantum efficiency, moisture resistance, and thermal stability can be expected in Mn 4+-doped fluoride single crystals, which are essential for high power applications. Herein, micrometer-size cubic K 2 SiF 6 :Mn 4+ (KSFM) single crystals were grown by a saturated crystallization method. The formation of Mn 4+-rare surface layer on KSFM single crystal particles was studied considering the crystallization process. The excellent performance of KSFM single crystal on moisture resistance, high quantum efficiency, thermal quenching stability, and effective heat dissipation were evaluated in detail. The as-fabricated KSFM single crystal phosphors converted white LEDs or LDs devices have the potential to be used for high-power and high-brightness backlight displays or lighting devices, and the result could initiate the exploration of new single crystal materials and Mn 4+-doped fluoride single crystals for other emerging applications. 2. Results and Discussion The schematic flow chart of this saturated crystallization method is shown in Figure 1a, and the typical KSFM single crystals Narrow-band red-emitting fluoride phosphors play a crucial role in lighting and backlight displays, whereas the stability issue is a major challenge. Here, highly stable K 2 SiF 6 :Mn 4+ (KSFM) single crystal phosphors with tunable sizes (20-1000 µm) are grown by a facile saturated crystallization method. The small specific surface area together with the unique Mn 4+-rare interface layer in KSFM single crystals enables the simultaneous fulfillment of high external quantum efficiency, excellent moisture, improved thermal quenching, and dissipation for high-power and laser-driven lighting applications. As a prototype, a warm white laser diode dev...

show abstract

“…In order to manufacture white light-emitting diodes (WLEDs) with low correlated color temperature (CCT < 4500 K) and good color rendering index (CRI, Ra > 80), − red-emitting phosphors are an essential component. Mn 4+ -activated fluorides, for example, A 2 XF 6 :Mn 4+ − and A 3 YF 6 :Mn 4+ (A = NH 4 , Cs, K, Na; X = Ti, Zr, Si, Ge; Y = Ga, Al) − are such phosphors. Among them, Mn 4+ -doped potassium fluorosilicate is widely used in commercial applications because of its high QY and narrowband emission .…”

Section: Introductionmentioning

confidence: 99%

High Water Resistance and Luminescent Thermal Stability of Li_yNa_(2–y)SiF₆: Mn⁴⁺ Red-Emitting Phosphor Induced by Codoping of Li⁺

et al. 2022

View full text Add to dashboard Cite

Mn 4+ -doped fluoride phosphors are efficient narrowband red-emitting phosphors for white light-emitting diodes (WLEDs) and backlight displays. However, erosion by moisture is the main obstacle that l i m i t s t h e i r a p p l i c a t i o n . I n t h i s w o r k , L N S F : M n 4 + (Li 0.06 Na 1.94 Si 0.94 Mn 0.06 F 6 ) with high quantum yield (QY), luminescent thermal stability, and waterproofness was synthesized using the H 2 O 2 -free r e a c t i o n m e t h o d a t r o o m t e m p e r a t u r e . C o m p a r e d t o NSF:Mn 4+ (Na 2 Mn 0.06 Si 0.94 F 6 ), the QY value, luminescence thermal stability, and water resistance of LNSF:Mn 4+ are obviously improved by codoping of Li + because of the formation of charge-carrier transfer (CT) and rare-Mn 4+ layer induced by codoping of Li + . The former produces the negative thermal quenching (NTQ) effect, which results in the improvement of the luminescent thermal stability. The latter can inhibit the hydrolysis of Mn 4+ on the surface of the sample, which leads to the enhancement of waterproofness. The formation mechanism of the rare-Mn 4+ layer is discussed. A prototype WLED emitting the ideal warm white light (CCT = 3173 K, Ra = 90.4) was assembled by coating a mixture of LNSF:Mn 4+ , yellow emitting phosphor (YAG:Ce 3+ ), and epoxy resin on the blue light InGaN chip, indicating that the performance of the WLED can be improved by using LNSF:Mn 4+ .

show abstract

New red phosphor ceramic K2SiF6:Mn4+

Cited by 27 publications

References 19 publications

A Stable and Efficient Red‐Emitting Color Converter Based on K₂SiF₆:Mn⁴⁺ Phosphor‐in‐Glass Film for Next‐Generation Laser‐Excited Lighting and Display

A Stable and Efficient Red‐Emitting Color Converter Based on K₂SiF₆:Mn⁴⁺ Phosphor‐in‐Glass Film for Next‐Generation Laser‐Excited Lighting and Display

Three Birds with One Stone: K₂SiF₆:Mn⁴⁺ Single Crystal Phosphors for High‐Power and Laser‐Driven Lighting

High Water Resistance and Luminescent Thermal Stability of Li_yNa_(2–y)SiF₆: Mn⁴⁺ Red-Emitting Phosphor Induced by Codoping of Li⁺

Contact Info

Product

Resources

About

New red phosphor ceramic K2SiF6:Mn4+

Cited by 27 publications

References 19 publications

A Stable and Efficient Red‐Emitting Color Converter Based on K2SiF6:Mn4+ Phosphor‐in‐Glass Film for Next‐Generation Laser‐Excited Lighting and Display

A Stable and Efficient Red‐Emitting Color Converter Based on K2SiF6:Mn4+ Phosphor‐in‐Glass Film for Next‐Generation Laser‐Excited Lighting and Display

Three Birds with One Stone: K2SiF6:Mn4+ Single Crystal Phosphors for High‐Power and Laser‐Driven Lighting

High Water Resistance and Luminescent Thermal Stability of LiyNa(2–y)SiF6: Mn4+ Red-Emitting Phosphor Induced by Codoping of Li+

Contact Info

Product

Resources

About

A Stable and Efficient Red‐Emitting Color Converter Based on K₂SiF₆:Mn⁴⁺ Phosphor‐in‐Glass Film for Next‐Generation Laser‐Excited Lighting and Display

A Stable and Efficient Red‐Emitting Color Converter Based on K₂SiF₆:Mn⁴⁺ Phosphor‐in‐Glass Film for Next‐Generation Laser‐Excited Lighting and Display

Three Birds with One Stone: K₂SiF₆:Mn⁴⁺ Single Crystal Phosphors for High‐Power and Laser‐Driven Lighting

High Water Resistance and Luminescent Thermal Stability of Li_yNa_(2–y)SiF₆: Mn⁴⁺ Red-Emitting Phosphor Induced by Codoping of Li⁺