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1 Jurnal f the Krean Ceramic Sciety Vl. 44, N. 3, pp. 147~151, Luminescence Characteristics f Mg Ba C-Dped Sr 2 :Eu Yellw Phsphr fr Light Emitting Dides Kyung Jae Chi, Sn Duk Jee,* Chang Hae Kim, Sang Hyuk Lee,* and H Kun Kim** Advanced Materials Divisin, Krea Research Institute f Chemical Technlgy, Daejen , Krea *Department f Technlgy Educatin, Krea Natinal University f Educatin, Chengwn , Krea **Department f Applied Chemistry, Hanyang University, Ansan , Krea (Received April 10, 2006; Accepted March 5, 2007) LED Mg Ba C-Dped Sr 2 :Eu xÿ Ÿp Á *Á½ wá x*á½y ** w yw yw *w w» **w w yw ( ; ) ABSTRACT An imprvement fr the efficiency f the Sr 2 :Eu yellw phsphr under the 450~470 nm excitatin range have been achieved by adding the c-dping element (Mg and Ba ) in the hst. White LEDs were fabricated thrugh an integratin f an blue (InGaN) chip (λ em =450 nm) and a blend f tw phsphrs (Mg, Ba :Eu yellw phsphr+cas:eu red phsphr) in a single package. The InGaN-based tw phsphr blends (Mg, Ba :Eu yellw phsphr+cas:eu red phsphr) LEDs shwed three bands at 450 nm, 550 nm and 640 nm, respectively. The 450 nm emissin band was due t a radiative recmbinatin frm an InGaN active layer. This 450 nm emissin was used as an ptical transitin f the Mg, Ba c-dped Sr 2 :Eu yellw phsphr and CaS:Eu red phsphr. As a cnsequence f a preparatin f white LEDs using the Mg, Ba cdped Sr 2 :Eu yellw phsphr and CaS:Eu red phsphr, the highest luminescence efficiency was btained at the 0.03 ml Ba cncentratin. At this time, the white LEDs shwed the CCT (5300 K), CRI (89.9) and luminus efficacy (17.34 lm/w). Key wrds : Phsphr, LED (Light Emitting Dide), PL, White LED lamp 1. ú» z» w eü k v p w v p š LED(lighting emitting dide)ƒ Ÿ wš. LED r ƒw ƒ p-n w y y d y w w w w. w y š{ LED œ 1993 e yw ùe w LED xw š, LED YAG xÿ ww LED LED x ƒ w z» š w Crrespnding authr : Kyung Jae Chi chikj@krict.re.kr Tel : Fax : w LED w ƒ š r»»», 10, š ù ü š, ù ƒ w y w ƒ w v w LED ƒ w. x LED w š ƒƒe ww. w» ƒ w š, ü» œw ù w. w» w e w» šz xÿ w. 1-3) Mg, Ba :Eu šz xÿ q { ƒ š YAG xÿ w LED xÿ. w LED š (lm/w) w t (CCT : crrelated clr temperature), š (CRI : clr rendering index) ƒ. Mg, 147

2 148 Á Á½ wá xá½y Ba :Eu xÿ CaS:Eu xÿ LED sw LED xwš,» ù Ÿz, t, CCT, CRI w. 4-7) 2. x Mg, Ba :Eu xÿ» w š (99.9%) SrCO 3, BaCO 3, MgO, SiO 2, Eu 2 O 3 w š w w w. ƒ ƒƒ e w, z yw w m w 40 yww. û ù m w» w 100 C 1 g. 3ƒ k Eu 2ƒ Eu y j» w 25% H 2 /N 2» 1100~ 1400 C ƒƒ 3 w w x Ÿ w w. ƒ 200 ml/min w. xÿ Ÿp Ÿ(PL)» rp v(xenn flash lamp) ü w Perkin Elmer LS 50 spectrmeter w d w. LED Lamp v Reflectr s Mg, Ba :Eu x Ÿ CaS:Eu xÿ (0.3 g:0.03 g) yww sw. d Optrnic Labratries OL 770-LED 20 ma w d w. 8) 3. š Sr 2 :Eu xÿ» Ÿ rp Fig. 1 ùkü.» rp r 300~430 nm¾ Fig. 1. Typical PL excitatin and emissin spectra f Sr 2 : Eu phsphr. Fig. 2. Phtluminescence emissin spectra f the Ba cdped effect n the emissin bands f 0.03 ml Eu cncentratin under the 455 nm excitatin.» ƒ š LED v InGaN(Blue LED) InGaN(UV LED) yw w LED xw. Ÿ rp q 520 nm s. w LED xw 4). Sr 2 :Eu xÿ Sr Ba eyw ùkù Ÿ rp Fig. 2 ùkü., Sr Ba eyw q 550 nm¾ wš, Ba ƒw q q wš { ƒw w š. Sr 2 w. Ba ƒ 0.01 ml š, Ba ƒ 0.05 ml ƒw ë. Sr 2 e m ey C- x w. ey Eu ƒ w w w w w. w k wù d-rbital w. 9,10) ã w, Sr Ba w ey C- ¼ ƒ ƒwš w d-rbital w z ƒ w Ÿ q q w. X- z y w Fig. 3 ùkü. Ba ƒ 0.01 ml 2θ=26.72, ùkù z vj Sr 2. Ba ey Sr 2 :Eu xÿ Mg ƒ { ƒ ƒ Ÿ rp Fig. 4 ùkü. Mg ƒ { 12% ƒw. š w wz

3 LED Mg ÁBa C-Dped Sr 2 :Eu xÿ Ÿp 149 Fig. 3. X-ray diffractin patterns f (Sr 1.97-x, Ba x ) :Eu 0.03 pwders. Fig. 5. Relative emissin spectra f Ba c-dped, Ba Mg :Eu and YAG:Ce under 455 nm and 465 nm excitatin. Fig. 4. Relative emissin spectra f Ba c-dped, Ba Mg :Eu under 455 nm excitatin. x 5 Sr 2 :Eu xÿ Mg ƒw Sr 3 MgSi 2 O 8 :Eu xÿ ë. w,» q 540 nm y ƒ Mg w wš w { ƒ j w. 6) Fig. 5 ƒƒ xÿ 455 nm, 465 nm» g d w Ÿ rp. Mg, Ba c-dped Sr 2 :Eu xÿ YAG:Ce xÿ» q { ùküš. f p w xÿ 300~430 nm¾ ƒ, 430 nm z w w š. w YAG xÿ 400 nm l ƒw ƒ 460 nm ƒ š z w. w, s xk š. LED Blue LED s xÿ yww Fig. 6. Relative emissin spectra f a white-emitting InGaNbased LED with different rati f epxy/ba Mg cdped Sr 2 :Eu phsphr under a 20 ma drive current. v Reflectr cup sw d w r p Fig. 6 ùkü. LED v 450 nm, 550 nm q ùküš. 450 nm q InGaN y l radiative recmbinatin ùkù vj. InGaN LED chip ù 450 nm Ÿ Mg, Ba :Eu xÿ». xÿ ƒ s s 450 nm rp š, xÿ w q 550 nm vjƒ ƒw š. xÿ s t y Fig. 7 ùkü. xÿ ƒw CIE X, CIE Y ƒw. q ùkù x Ÿ ƒ w 450 nm» 44«3y(2007)

4 150 Á Á½ wá xá½y Fig. 7. CIE chrmaticity pints f InGaN-based Ba Mg cdped Sr 2 :Eu LED. Table 1. The Measured Parameter f a White-Emitting InGaN- Based LED with Different Rati f Epxy/Ba Mg C-Dped Sr 2 :Eu Phsphr Under a 20 ma Drive Current Epxy:Phsphr CIE X CIE Y CCT (K) wš, s xÿ ƒ» w Ÿw 550 nm ƒw. InGaN(450 nm) chip w xÿ sw ùkú t t w w. Table 1 LED Lamp w t, (CCT), (CRI) Ÿ z OL 770-LED w 20 ma d w w. t xÿ ƒw Ÿz ƒw CRI w w š. Mg, Ba :Eu xÿ xÿ CaS:Eu yww LED w. Fig. 8 YAG xÿ ƒ xÿ yww w LED w ùkü v. Table 2 Mg, Ba :Eu xÿ xÿ CaS:Eu (0.3 g:0.03 g) yww Blue (InGaN) LED chip sw LED w, YAG xÿ w d w CRI(89.9), Ÿ z lm/w w Ÿp ùküš. š Mg, Ba 4. CRI Efficacy (lm/w) 1.0 g:0.344 g g:0.477 g g:0.705 g :Eu Fig. 8. Relative emissin spectra f a white-emitting InGaNbased YAG:Ce LED and InGaN-based tw phsphr blends (Ba Mg :Eu+CaS:Eu) LED under a 20 ma drive current. Table 2. The Measured Parameter f a White-Emitting InGaN- Based YAG:Ce LED and InGaN-Based Tw Phsphr Blends (Ba Mg C-Dped Sr 2 :Eu + CaS:Eu) LED Under a 20 ma Drive Current Phsphr CIE X CIE Y CCT (K) xÿ w w, q 550 nm š s Ÿ rp. Ba ƒ 0.3 ml, Ÿz Mg, Ba :Eu xÿ w LED Lamp w YAG xÿ w Ÿz. w, w t, CCT, CRI š w w» w xÿ yw w w. Mg, Ba :Eu xÿ CaS:Eu xÿ Blue(InGaN) LED chip ww LED x w, CCT(5400 K), CRI(89.9), Ÿz lm/w ùkû. REFERENCES CRI Efficacy (lm/w) YAG:Ce Tw Phsphr S. Nakamura and G. Fasl, The Blue Laser Dide: GaN Based Light Emitters and Lasers, pp , Springer, Berlin, Y. Narukawa, I. Niki, K. Izun, M. Yamada, Y. Murazaki, and T. Mukai, Phsphr-Cnversin White Light Emitting Dide Using InGaN Near-Ultravilet Chip, Jpn. J. Appl. Phys., (2002). w wz

5 LED Mg ÁBa C-Dped Sr 2 :Eu xÿ Ÿp R. Mueller-Mach and G. O. Mueller, White Light Emitting Dides fr Illuminatin, Prc. SPIE., (2000). 4. J. K. Park, M. A. Lim, C. H. Kim, and H. D. Park, White Light-Emitting Dides f GaN-Based Sr 2 :Eu and the Luminescent Prperties, Appl. Phys. Lett., (2003). 5. J. K. Park, K. J. Chi, C. H. Kim, H. D. Park, and S. Y. Chi, Optical Prperties f Eu -Activated Sr 2 Phsphr fr Light-Emitting Dides, Electrchemical and Slid-State Lett., 7 H15-17 (2004). 6. J. K. Park, K. J. Chi, S. H. Park, C. H. Kim, and H. K. Kim, Applicatin f Mg, Ba C-Dped Sr 2 :Eu Yellw Phsphr fr White-Light-Emitting Dides, J. Electrchem. Sc., 152 H (2005). 7. S. H. M. Prt and G. Blasse, The Influence f the Hst Lattice in the Luminescence f Divalent Eurpium, J. Lumin., (1997). 8. K. J. Chi, J. K. Park, K. N. Kim, C. H. Kim, and H. K. Kim, Luminescence Characteristics f Sr 3 MgSi 2 O 8 :Eu Blue Phsphr fr Light Emitting Dides(in Krean), J. Kr. Ceram. Sc., (2004). 9. S. H. M. Prt, W. Janssen, and G. Blasse, Optical Prperties f Eu -Activated Orthsilicates and Orthphsphates, J. Ally Cmp., (1997). 10. S. H. M. Prt, H. M. Reijnhudt, H. O. T. van Kuip, and G. Blasse, Luminescence f Eu in Silicate Hast Lattices with Alkaline Earth Ins in a Raw, J. Ally Cmp., (1996). 44«3y(2007)