Structural and Thermal Properties of Tb, Ce Doped Y&amp;lt;sub&amp;gt;2.97&amp;lt;/sub&amp;gt;Gd&amp;lt;sub&amp;gt;0.03&amp;lt;/sub&amp;gt;Al&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;Ga&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;O&amp;lt;sub&amp;gt;12&amp;lt;/sub&amp;gt; Single Crystals

Faheem, Mohammad; Lynn, Kelvin G.

doi:10.4236/ajac.2014.511078

Cited by 6 publications

(2 citation statements)

References 18 publications

(15 reference statements)

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“…White LEDs, based on blue LED chips (have been deve− loped since 1991, first time by Nichia Co.) coated with yel− low emitting phosphor were first reported in 1996, and Ce 3+ doped YAG phosphor, with the general formula: Ce:YAG has been available since 1960s, but the YAG:Ce is considered a cool phosphor, due to the lack of the red com− ponent [5][6][7][8][9]. In the last years, the research is turning to co−doping the YAG:Ce, in order to shift the emission spec− trum by partially substituting the Y or Al cations with differ− ent ions.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of YAG:Ce phosphors for white LEDs

Ţucureanu

Matei

Avram

2015

Opto-Electronics Review

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Worldwide commercial interest in the production of cerium doped yttrium aluminium garnet (YAG:Ce) phosphors is reflected in the widespread use of white light emitting devices. Despite of the fact that YAG:Ce is considered a “cool phosphor” it is the most important in white LED technology. This article reviews the developed techniques for producing phosphors with superior photoluminescence efficiency, including solid-state reaction, sol-gel and (co)precipitation methods. Also, by co-doping with rare earth elements, a red/blue shift is reached in the spectrum. The characteristics of YAG:Ce phosphors are investigated because the properties of the phosphors are strongly influenced by the synthesis routes and the sintering temperature treatment. After the phase analysis, morphology and emission studies of the phosphors there may be seen the conditions when the transition from the amorphous phase to the crystalline phase appears, when luminescent properties are influenced by the crystalline form, purity, average size of the particles, co-doping and so on.

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Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of YAG:Ce phosphors for white LEDs

Ţucureanu

Matei

Avram

2015

Opto-Electronics Review

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“…Recent research has demonstrated the necessity of these studies by investigating the structural and thermal properties of Tb, Ce doped Y 3 Al 5 O 12 (YAG) single crystals. 13,14 The results act as pointers to the research that needs to be undertaken in parallel to both develop radical designs of LDIL modules and the associated single crystals used as emitting targets. In this report we have focused on studying different crystal sizes of the same phosphor material with the same LDs.…”

mentioning

confidence: 96%

Investigating the Emission Characteristics of Single Crystal YAG When Activated by High Power Laser Beams

Salimian

Silver

Fern

et al. 2016

ECS J. Solid State Sci. Technol.

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Limitations associated with light emitting diodes (LEDs) operating under high current densities due to the efficiency droop has created a need to look for alternative light sources; here we report investigations on the potential of laser diodes (LDs) for high brightness lighting solutions. High power laser diodes require phosphor targets with certain performance criteria such as high thermal conductivity, efficiency and structural geometry. Here we examine the possibility of using single crystal YAG:Ce phosphor materials as potential targets for generation of light via laser diodes. We report on the emission properties of the crystals with different sizes and examine the effect of laser beam incident angle incident on crystal target emission. Light emitting diodes (LEDs) are the current lighting technology solution gaining a wide adoption in a variety of commercial applications. They are now the dominant new lighting in office, public and domestic application, in addition they have almost completely covered the automotive head lamp market and now they are finding their way into more sophisticated instruments such as solar simulators. The best commercial LED's efficiencies are now above 60% and they are the most energy saving solution available. However there is a fundamental issue undermining their performance when they are considered for high brightness lighting applications. To generate high emission intensities, LEDs need to be driven at high current densities at which point their efficiency suffers from a phenomenon described as the efficiency droop. The efficiency droop's origin is rooted in a variety of complex processes including; Auger recombination, overflow of carriers from rich potential minima and carrier leakage out of active region.1-8 So far the highest luminous efficacies reported on LEDs are based on driving them at low current densities on the order of >11 Acm −2 . 9,10 In contrast to LEDs, Laser Diodes (LDs) can operate at very high current densities without suffering from efficiency droop. 11,12 However currently the LD's overall efficiency is well below that of LEDs and their application in lighting will require radical packaging designs and arrangement of the laser diode and phosphor target assemblies. To be able to manipulate the emission spectrum of devices based on LD induced lighting (LDIL) the type of phosphor targets and the level of impurities constituting the phosphor target material will need to be studied and adjusted. Recent research has demonstrated the necessity of these studies by investigating the structural and thermal properties of Tb, Ce doped Y 3 Al 5 O 12 (YAG) single crystals. 13,14 The results act as pointers to the research that needs to be undertaken in parallel to both develop radical designs of LDIL modules and the associated single crystals used as emitting targets. In this report we have focused on studying different crystal sizes of the same phosphor material with the same LDs. We have carried out studies on beam incident angle and relationship between the emiss...

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