CaMg2Al16O27:Mn4+-based Red Phosphor: A Potential Color Converter for High-Powered Warm W-LED

Wang, Bo; Lin, Hang; Xu, Jü; Chen, Hui; Wang, Yuansheng

doi:10.1021/am507316b

Cited by 412 publications

(220 citation statements)

References 49 publications

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“…Besides, for actual application in a WLED, it is necessary to study the resistance of Mn 4+ PL to thermal impact. This is 4 because when the driving current increases, the chip temperature easily becomes higher than 150 o C. For instance we have observed the temperature of 156 o C for a LuVO 4 :Bi 3+ coated LED lamp at 80 mA. 16 The aims of this work were to first identify the site occupancy preference of Mn 4+ ions once doped into the compound of Sr 4 Al 14 O 25 by calculation, and then to elucidate the mechanism on how Mg 2+ addition can enhance Mn 4+ PL.…”

Section: Introductionmentioning

confidence: 97%

Site Occupancy Preference, Enhancement Mechanism, and Thermal Resistance of Mn⁴⁺ Red Luminescence in Sr₄Al₁₄O₂₅: Mn⁴⁺ for Warm WLEDs

et al. 2015

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Red phosphors play an indispensable role in phosphor-based warm white light emitting diodes (WLEDs). We demonstrated recently that the non-rare-earth phosphor Sr 4 Al 14 O 25 :Mn 4+ exhibits red luminescence even more intensely than the commercial Mn 4+ phosphor 3.5MgO.0.5MgF 2 .GeO 2 :Mn 4+ upon blue excitation. Herein, on the basis of crystal field calculations employing the exchange charge model, we identify the energy levels of three types of Mn 4+ ions situated at Al 3+ sites in the Sr 4 Al 14 O 25 crystal lattice and find that the doped manganese ions occupy preferentially the Al4 and Al5 more highly covalent sites rather than the Al6 site. We report that the Mn 4+ luminescence can be enhanced upon the inclusion of Mg 2+ in the synthesis reaction.The mechanisms for this effect comprise the lower nonradiative decay rate from the 2 E g state due to the reduction in energy migration along Mn 4+ ions to killer sites and also the morphology evolution from orderly layered smooth nanosheets to irregular nanoparticles disorderly compacted in porous bundles. Interestingly, various other phases are formed upon the addition of Mg 2+ . The resistance of Mn 4+ photoluminescence in the phosphor to thermal impact has also been studied and no obvious thermal degradation after a cycle experiment by heating and cooling the sample between 25 o C and 300 o C was found. As proof of concept, a warm perception WLED has been made when the phosphor was applied to the package of a blue LED chip and YAG:Ce.

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Section: Introductionmentioning

confidence: 97%

Site Occupancy Preference, Enhancement Mechanism, and Thermal Resistance of Mn⁴⁺ Red Luminescence in Sr₄Al₁₄O₂₅: Mn⁴⁺ for Warm WLEDs

et al. 2015

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“…They found the glass composition for preventing recrystallization of CASN:Eu 2+ phosphor and successfully fabricated a wLED with the best combination of each phosphor, which had a CCT of 3789 K and a CRI of 93. Ahn et al 79 employed a PiG with a low sintering temperature based on the SiO 2 82 with the commercial YAG:Ce 3+ yellow phosphor. These red phosphors were proposed to solve the recrystallization problem.…”

Section: Aspects Of Improvement For High-power Applicationsmentioning

confidence: 99%

Review—Phosphor Plates for High-Power LED Applications: Challenges and Opportunities toward Perfect Lighting

Kim

Viswanath

Unithrattil

et al. 2017

ECS J. Solid State Sci. Technol.

127

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In the past decades, solid-state lighting based on phosphors as energy converters has been a fast-growing industry. Phosphorconverted white light-emitting diodes (pc-wLEDs) enable high-power applications and miniaturization; for this, the phosphor must have good stability and high efficiency. In order to satisfy this demand, phosphor plates have been proposed instead of conventional organic-based phosphor binders. In this review, such phosphor plates are categorized according to their synthesis methods, and the advantages and disadvantages of each category are detailed. In addition, we describe the major aspects of phosphor plates that require improvement for applications in high-power devices. For the fabrication of high-power LEDs, the phosphor configuration, color purity, porosity, and particle size of glass powders are key properties to enhance the luminescence efficiency and reduce the generation of heat inside wLED packages, thereby improving thermal stability. The advent of authentic, energy-efficient lighting in the home and workplace significantly affected the modern way of life. Beginning with the mass production of incandescent light bulbs, and with the subsequent evolution of fluorescence lights, lighting technology has developed rapidly in the last few decades. Since Edison's incandescent bulb in 1879, 1 artificial lighting has been developed to increase power output and decrease the size of the system. The development of red light-emitting diodes (LEDs) in 1962 2 and blue LEDs in 1993 3 allowed innovation in lighting and display. In particular, combinations of blue LEDs and yellow phosphors are used for many applications because they can realize cheap and efficient white solid-state lighting with several advantages including long lifetimes, eco-friendly behavior, and the capacity of miniaturization. 4-6In phosphor-converted white LEDs (pc-wLEDs), the phosphor converter dispersed in silicon resin (phosphor-in-silicon; PiS) is directly packed on a blue InGaN chip.7 When driven by a bias current, the emitted blue light absorbed by the phosphor is emitted as yellow light; together with the transmitted blue light, this constitutes white luminescence. However, this method lacks a red component, which entails the drawbacks of a poor color rendering index (CRI) and limited correlated color temperature (CCT). To overcome these drawbacks, one proposed method mixes yellow phosphors with phosphors having green to red emissions under blue excitation. 8 In pc-wLEDs, the color is primarily determined by the ratio of the blue emission from the LED chip to the yellow to red emission from the phosphor. However, the efficacy and brightness are determined by the converted yellow to red emission, as it contributes the bulk of lumens. In this configuration, the heat generated from the LED chip and phosphor cannot be efficiently dissipated because of the poor thermal stability and weak thermal conductivity of the resin, which causes luminous decay and color shifting in white light-emitting diodes (wLEDs).9 When the tempe...

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“…At present, the phosphor-converted w-LED based on the "blue chips + yellow phosphor" technique has become a major approach to generate white light, and the yellow phosphor YAG:Ce 3+ dispersed in silicone (phosphor-in-silicone, PiS) is packed on the InGaN blue chips by conformal coating [4]. Unfortunately, the organic encapsulants featured with poor thermal conductivity and thermal/chemical stability would undergo aging and yellowing during the long-term service, which results in luminescent degradation and color aberration [5,6]. This problem becomes more and more serious with increasing the input current necessary to achieve high-power w-LEDs due to the elevation of surrounding temperature.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

CaMg₂Al₁₆O₂₇:Mn⁴⁺-based Red Phosphor: A Potential Color Converter for High-Powered Warm W-LED

Cited by 412 publications

References 49 publications

Site Occupancy Preference, Enhancement Mechanism, and Thermal Resistance of Mn⁴⁺ Red Luminescence in Sr₄Al₁₄O₂₅: Mn⁴⁺ for Warm WLEDs

Site Occupancy Preference, Enhancement Mechanism, and Thermal Resistance of Mn⁴⁺ Red Luminescence in Sr₄Al₁₄O₂₅: Mn⁴⁺ for Warm WLEDs

Review—Phosphor Plates for High-Power LED Applications: Challenges and Opportunities toward Perfect Lighting

Highly thermal-stable warm w-LED based on Ce:YAG PiG stacked with a red phosphor layer

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CaMg2Al16O27:Mn4+-based Red Phosphor: A Potential Color Converter for High-Powered Warm W-LED

Cited by 412 publications

References 49 publications

Site Occupancy Preference, Enhancement Mechanism, and Thermal Resistance of Mn4+ Red Luminescence in Sr4Al14O25: Mn4+ for Warm WLEDs

Site Occupancy Preference, Enhancement Mechanism, and Thermal Resistance of Mn4+ Red Luminescence in Sr4Al14O25: Mn4+ for Warm WLEDs

Review—Phosphor Plates for High-Power LED Applications: Challenges and Opportunities toward Perfect Lighting

Highly thermal-stable warm w-LED based on Ce:YAG PiG stacked with a red phosphor layer

Contact Info

Product

Resources

About

CaMg₂Al₁₆O₂₇:Mn⁴⁺-based Red Phosphor: A Potential Color Converter for High-Powered Warm W-LED

Site Occupancy Preference, Enhancement Mechanism, and Thermal Resistance of Mn⁴⁺ Red Luminescence in Sr₄Al₁₄O₂₅: Mn⁴⁺ for Warm WLEDs

Site Occupancy Preference, Enhancement Mechanism, and Thermal Resistance of Mn⁴⁺ Red Luminescence in Sr₄Al₁₄O₂₅: Mn⁴⁺ for Warm WLEDs