Application of strontium silicate yellow phosphor for white light-emitting diodes

Park, Joung Kyu; Kim, Chang Hae; Park, Seung Hyok; Park, Hee Dong; Choi, Se Young

doi:10.1063/1.1667620

Cited by 400 publications

(152 citation statements)

References 12 publications

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“…In addition, they should also have the following characteristics: (i) high conversion efficiency; (ii) high stability against chemical, oxygen, carbon dioxide, and moisture; (iii) low thermal quenching; (iv) small and uniform particle size (5-20 mm); and (v) appropriate emission colors. The phosphor most commonly utilized in bichromatic white LEDs is the yellow-emitting (Y 1Àa Gd a ) 3 (Al 1Àb Ga b ) O 12 :Ce 3+ (YAG:Ce) [1]. Other types of phosphor such as orthosilicates [3,4], aluminates [5], and sulfides [5,6] have also been used in white LEDs.…”

Section: Introductionmentioning

confidence: 99%

“…The phosphor most commonly utilized in bichromatic white LEDs is the yellow-emitting (Y 1Àa Gd a ) 3 (Al 1Àb Ga b ) O 12 :Ce 3+ (YAG:Ce) [1]. Other types of phosphor such as orthosilicates [3,4], aluminates [5], and sulfides [5,6] have also been used in white LEDs. However, most oxide-based phosphors have low absorption in the visible-light spectrum, making it impossible for them to be coupled with blue LEDs.…”

Section: Introductionmentioning

confidence: 99%

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Silicon-based oxynitride and nitride phosphors for white LEDs—A review

Xie

Hirosaki

2007

Science and Technology of Advanced Materials

936

598

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As a novel class of inorganic phosphors, oxynitride and nitride luminescent materials have received considerable attention because of their potential applications in solid-state lightings and displays. In this review we focus on recent developments in the preparation, crystal structure, luminescence and applications of silicon-based oxynitride and nitride phosphors for white light-emitting diodes (LEDs). The structures of silicon-based oxynitrides and nitrides (i.e., nitridosilicates, nitridoaluminosilicates, oxonitridosilicates, oxonitridoaluminosilicates, and sialons) are generally built up of networks of crosslinking SiN 4 tetrahedra. This is anticipated to significantly lower the excited state of the 5d electrons of doped rare-earth elements due to large crystal-field splitting and a strong nephelauxetic effect. This enables the silicon-based oxynitride and nitride phosphors to have a broad excitation band extending from the ultraviolet to visible-light range, and thus strongly absorb blue-to-green light. The structural versatility of oxynitride and nitride phosphors makes it possible to attain all the emission colors of blue, green, yellow, and red; thus, they are suitable for use in white LEDs. This novel class of phosphors has demonstrated its superior suitability for use in white LEDs and can be used in bichromatic or multichromatic LEDs with excellent properties of high luminous efficacy, high chromatic stability, a wide range of white light with adjustable correlated color temperatures (CCTs), and brilliant color-rendering properties. r

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Silicon-based oxynitride and nitride phosphors for white LEDs—A review

Xie

Hirosaki

2007

Science and Technology of Advanced Materials

936

598

View full text Add to dashboard Cite

show abstract

“…, and the dopant Eu 2+ is comparable with the difference between the anion radii [ [4] r(N 3− ) - [4] r(O 2− ) = 0.08 Å]. With the significant dispersion of size △r [ [8] r(Eu 2+ ) - [8] r(Ca Figure 3a.…”

Section: +mentioning

confidence: 73%

“…Phosphor-converted white light devices consist of a blue or near-UV chip as excitation source, and have appropriate phosphor compositions that down-convert a portion of the chip emission to longer wavelengths. Therefore, phosphor has an important role in solid-state lighting (SSL), and should possess high chemical/thermal stability, high quantum efficiency (QE), suitable excitation and emission spectra, high reliability, and low cost [4,5]. Although numerous phosphors have already been investigated or developed for SSL applications, only a few of them can be practically applied to wLEDs.…”

Section: Introductionmentioning

confidence: 99%

Thermal effects in (oxy)nitride phosphors

Lin

Liu

2014

J Sol State Light

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Technologies that control the chemical composition of white lighting-emitting diodes are promising means to enhance thermal properties and renew spectra generation. Although (oxy)nitride red phosphors have been available for more than a decade, the drawbacks of these devices still evidently remain with respect to the local environments of activators in a variety of nitridosilicates. Thermal effects, such as, thermal quenching, thermal ionization, and thermal degradation, are technologically important parameters that determine product reliability. In recent years, red phosphors, which can alter novel complexes with particular wavelengths, have been easily synthesized and used to minimize losses during energy conversion process. Silicon nitride ceramics contain a more highly condensed network compared with silicate because of the higher degree of cross-linking, edge-sharing SiN 4 tetrahedron, and more covalent and stronger crystal field splitting. To provide a reasonable explanation for the relationship between photoluminescence and structure, an empirical model has been proposed, in which the changes in the chemical environment of the activators are attributed to strains resulting from atom displacements. In addition, the development of high-efficiency and cost-effective light-emitting diodes based on these luminescent materials has difficult challenges.

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“…Several approaches widely used today for the generation of white light using LEDs have been introduced in past studies [1,2]. Among them, there is a fascinating approach to use a blue LED and phosphors, called as phosphor converted (PC) white LEDs [3][4][5][6]. A PC white LED consists of a blue LED and yellow phosphors.…”

Section: Introductionmentioning

confidence: 99%

Effects of Current Modulation Conditions on the Chromaticity of Phosphor Converted (PC) White LEDs

Kim

et al. 2012

Journal of the Optical Society of Korea

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For two well-known modulation methods, stepwise current modulation (SCM) and pulse width modulation (PWM), the effects of driving current modulation conditions on chromaticity were experimentally investigated in a white LED lighting system. For the experimental implementation of both SCM and PWM, a white LED lighting was fabricated using phosphor converted (PC) white light emitting diodes (LEDs) and a driving circuit module was developed. By using them, the variations of illuminance, color coordinates, and spectrum were evaluated under various forward current conditions. Through the analysis in color coordinates, yellow shift in SCM and blue shift in PWM were observed on chromaticity diagrams with increasing average driving current. In addition, in order to analyze color deviation quantitatively, color distance before and after current increase, and the correlated color temperature (CCT) were calculated. As a result, for the white LED lighting in both modulation conditions, the maximum difference in the calculated CCT was obtained close to 1000 K. It means that careful consideration is required to be taken in the design of illumination systems to avoid serious problems such industrial accidents.

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Application of strontium silicate yellow phosphor for white light-emitting diodes

Cited by 400 publications

References 12 publications

Silicon-based oxynitride and nitride phosphors for white LEDs—A review

Silicon-based oxynitride and nitride phosphors for white LEDs—A review

Thermal effects in (oxy)nitride phosphors

Effects of Current Modulation Conditions on the Chromaticity of Phosphor Converted (PC) White LEDs

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