Journal of the Ceramic Society of Japan 115 [10] 623 627 (2007) Paper ñú ù é Ý p Eu 2 è ì u } u ó 565 0871 2 1 560 8531 1 3 póåíüéëáë ~åç `Ü~ê~ÅíÉêáò~íáçå çñ pê O pá R k U Wbì O müçëéüçê rëáåö píêçåíáìã `~êäçñóä~íé Takashi HORIKAWA, Masahiro FUJITANI, Xianqing PIAO, Hiromasa HANZAWA and Ken-ichi MACHIDA Center for Advanced Science and Innovation, Osaka University, 2 1, Yamadaoka, Suita, Osaka 565 0871 Graduate School of Engineering Science, Osaka University, 1 3, Machikaneyama, Toyonaka, Osaka 560 8531 Divalent europium ion doped metal nitride phosphor, of Sr 2 Si 5 N 8 Eu 2, was synthesized by using Sr carboxylates as a reducing agent and the preparation conditions were optimized. The obtained samples derived from Sr acetate doped with 4 at Eu 2 to Sr content showed a strong emission at about 630 nm under the excitation at 449 nm. The emission intensity was about 136 of that of a commercially available YAG Ce 3 P46 Y3 standard phosphor, and the residual oxygen and carbon contents were 0.88 and 0.04, respectively. All these values were better than those for the same composition of Sr 2 Si 5 N 8 Eu 2 prepared by the conventional CRN method. The excellent quality and the suitable CIE chromaticity coordinates of 0.645, 0.355 suggest that this phosphor is one of possible candidates for the red color component of white LEDs. Received July 3, 2007; Accepted August 24, 2007 Key-words : Metal nitride phosphor, Divalent europium, White LED, Red emission, Molecular carbon reductant Å u º Å 3 Ù Ú º Å Ûºæÿ ì h Ò Ó Õ { œ Ò ž þ Ú u LED Å LED ùù r 1 ù r 2 Ê ÙÊ LED Ý Ý r LED Ò Ú n Û Ó ñú r Ê LED YAG:Ce 3 Yttrium Aluminum Garnet Ý Ý r Û 1 Ò ñú Å LED 1 ù r Ó LED j í ú ÿ Õ t Û Ó Á10 1,2 Ú 1 ù r Õ š Ò u Ò Ý Ò LED Þ ø Eu 2 Ý CaS:Eu 2 Ù Ú 3,4 Á Ë Ó Ò LED Û ÁÝÓ Ë ÙÊ Ca-a-SiAlON:Eu 2 5 8 M 2 Si 5 N 8 :Eu 2 M Ca, Sr, Ba 9,10 CaAlSiN 3 :Eu 2 11 12 ÙÊ Ý Ò Ú Ú p Û Ca 3 N 2 Ò Ù Õ œ ý ÊÚ CaAl 2 Si 10 N 16 :Eu 2, Ca 2 Si 5 N 8 :Eu 2 ÙÊ Sr 2 Si 5 N 8 :Eu 2 Ý ÙÊ Ý p pý Ó œêñ CRN: Carbothemal Reduction and Nitriding Ù 13 15 ÙÛ Ú p ² uú Ù Ý Ò z Û ý Sr 2 Si 5 N 8 :Eu 2 Ý Ý Ú{ ñú ù é ÙÛ Sr 2 Si 5 N 8 :Eu 2 Ý Ý z LED Ýø šð é šð p n Ê Ú Ú ÙÛ ÁÙ Sr 2 Si 5 N 8 :Eu 2 p ñú ù é 623
624 ñú ù é Ý p Eu 2 è ì ñú ù Sr HCOO 2 ñú ù Sr CH 3 COO 2,Aldrich è ñú ù Sr C 2 H 5 COO 2 Si 3 N 4 99.8 ý Eu 2 O 3 99.9 ÙÊ ë Ý Sr HCOO 2 ÙÊ Sr C 2 H 5 COO 2 SrCO 3 99.9 ë Ý 0.5 M HCOOH ë ÙÊ C 2 H 5 COOH œ 100?C º ² Ý õ» Ó Ý Sr HCOO 2 ÙÊ Sr C 2 H 5 COO 2 X XRD, Rigaku, RINT 2200 Ù ø Eu 2 ² Sr 4.0 at Ú p Ý º Ý 30 mlmin 1500 1650?C 4 6 p Ý XRD Ù ø ñ íú t F 4500 Ý ø p ÙÊ ² æÿ ì n X EDX, HORIBA, EMAX EX 220SE ÙÊ HORIBA, EMGA 550 ÙÛ Ýø ÙÊ r n Ùʺ p ã ø ó Ý ø Fig. 1. XRD patterns for the synthesized samples by using a carbon powder and b Sr CH 3 COO 2 as a reducing agent. Ê p Ò Ý Ú p XRD Ý a í Ð s Sr 2 Si 5 N 8 JCPDS 85 0101 Ú Eu Sr ú Ê Ú Sr 2 Si 5 N 8 :Eu 2 Ý Ý Sr CH 3 COO 2 Ý p z ÙÛ 1650?C 6 Ýø p Sr CH 3 COO 2 SrCO 3 š 3 2 mol š Ú p XRD Ý 1 b CRN Ž ÿ í s Sr 2 Si 5 N 8 Sr CH 3 COO 2 Ý Ó Sr 2 Si 5 N 8 :Eu 2 Ý uú p ñ íú Ý YAG:Ce 3 P46 Y3 è úýíñ Ó Sr 2 Si 5 N 8 Eu 2 p ñ íú ý î ÙÊ ñ íú 633 ÙÊ 449 nm Ú ñ íú 350 500 nm Eu 2 4f 7 q4f 6 5d û íýó 350 nm þú í Eu 2 è Ý š þú Ò š Ù r ñ íú í 632 nm CRN p YAG:Ce 3 115 Sr CH 3 COO 2 Ó 136 þú n ñ íú š Ú Sr CH 3 COO 2 Ý r 600 nm ÙÛ Á Ú Û Ý Fig. 2. Excitation and emission spectra for the synthesized samples by using carbon powder dashed line and Sr CH 3 COO 2 solid line as a reducing agent together with those for commercially available YAG Ce 3 standard phosphor dotted line. Sr 2 Si 5 N 8 :Eu 2 YAG:Ce 3 Ý LED 160?C YAG:Ce 3 40 šð Sr 2 Si 5 N 8 :Eu 2 81 Ý ÙÛ Ú p Û ÝÓ Sr 2 Si 5 N 8 :Eu 2 Ž SiN 4 ý ú Ó Ò 16 u Ù ƒ Ý Ú Ò Ê Ú Ú p Ù Ê 0.88, 0.04 mass Û CRN 1.09, 0.3 mass ÙÛÓ Ú Ú Sr 2 Si 5 N 8 :Eu 2 CIE Commission Internationale de l'eclairage 1931 Ý Ò x, y 0.645, 0.355 Û Ý
Journal of the Ceramic Society of Japan 115 [10] 2007 625 Fig. 3. Diffuse reflectance spectra for the synthesized samples by using carbon powder and Sr CH 3 COO 2 as a reducing agent. Fig. 5. EDX spectra for the synthesized samples with a heating rate of 10?C a and 150?C b. Fig. 4. Temperature dependence of the emission intensity for synthesized Sr 2 Si 5 N 8 Eu 2 solid circle and commercially available YAG Ce 3 standard phosphor open triangle. ÙÛ Sr CH 3 COO 2 Ý ÙÛ { Sr 2 Si 5 N 8 :Eu 2 uú Sr 2 Si 5 N 8 :Eu 2 Ý ÁÙ Û Ý u LED 160?C Ó Ò LED {{ Ž Ê Ž Ê Sr C 2 H 5 COO 2 Ý p 800?C 2 1200?C 2 1500?C 4 Ú r Sr C 2 H 5 COO 2 pý u Ý10?Cmin Ú150?Cmin z Ò 1500?C u 4 Ú Ó Ù ÿ Ó Ú XRD þú Ú pó Sr 2 Si 5 N 8 :Eu 2 SrSi 2 O 2 N 2 : Eu 2 p Si 3 N 4 í ÿ Ú EDX ÙÛ p Ýø Ú ñ íú Ý u 10?Cmin ñ íú a í u Ý150?Cmin ñ íú b í Û Ú u u Õ é æÿ ì Ú Õ ² u œ Ò C C q C H q ø Ò Ê Ú æÿ ì C C šð C H r 68 kjmol Õ u ë îý œ êñ Ï Ê Ú ÙÊÊ ÙÛ é Ý p Ý { Ò ² u r Ù u XRD í Å ë î Ò Ê Ú 1500?C Sr 2 Si 5 N 8 :Eu 2 Ú Ú é Þ p { Ú é p pý Ý 150?C min 1650?C u 6 Ú XRD Ý Sr HCOO 2 Ý p p a SrSi 2 O 2 N 2 :Eu 2 Ý Sr CH 3 COO 2 p p b ÙÊ Sr C 2 H 5 COO 2 p p c Sr 2 Si 5 N 8 :Eu 2 SrSi 2 O 2 N 2 :Eu 2 Ý Û Sr 2 Si 5 N 8 :Eu 2 Ý Ú
626 ñú ù é Ý p Eu 2 è Fig. 6. XRD patterns for the synthesized samples by using a Sr HCOO 2, b Sr CH 3 COO 2 and c Sr C 2 H 5 COO 2 as a starting material. ñ íú ý î ÙÊ ñ íú Sr HCOO 2 p a 575 nm 330 nm Sr CH 3 COO 2 p b ÙÊ Sr C 2 H 5 COO 2 p c 635 nm 445 nm p a ñ íú 500 750 nm û Ó r p b ÙÊ c ñ íú í 635 nm þ Ú Sr 2 Si 5 N 8 :Eu 2 í 2 Sr 2 Si 5 N 8 :Eu 2 ñ íú šð 500 580 nm û 6 XRD Ó Ê Ó íý SrSi 2 O 2 N 2 :Eu 2 17 Ê Ú Ú ÙÛ é Ý p ŽÝÊ Ê Û Eu Sr ú Ê š ù CRN Ê Ú p SrCO 3 Ý 950?C Ý SrO Si 3 N 4 ÙÊ 1200?C Sr Si SrSi 2 O 2 N 2 Ý Ê Ú Ú p Sr ÙÊ Si š š Ò Sr Si Û 1600?C ÙÛ SrSi 2 O 2 N 2 Sr 2 Si 5 N 8 Ê Ú Sr HCOO 2 Ý p u Sr HCOO 2 1 ø Ê Ú Sr HCOO 2 qsro 2CO H 2 O 23Si 3 N 4 H 2 OqSi 2 ON 2 H 2 N 2 SrO Si 2 ON 2 qsrsi 2 O 2 N 2 1 2 3 œ Si 3 N 4 Si 2 ON 2 2 SrO Ú SrSi 2 O 2 N 2 Ê Ú 3 6 ÙÊ 7 Sr 2 Si 5 N 8 þú Ò Ú Ò Ž Sr CH 3 COO 2 ÙÊ Sr C 2 H 5 COO 2 4 5 ø Ê Ú Sr CH 3 COO 2 qsro 2CO H 2 O 2C 2H 2 Sr C 2 H 5 COO 2 qsro 2CO H 2 O 4C 4H 2 4 5 Sr HCOO 2 Ž 2 ÙÊ 3 ÙÛ SrSi 2 O 2 N 2 Ê Ú Ú Sr 2 Si 5 N 8 Fig. 7. Excitation and emission spectra for the synthesized samples by using a Sr HCOO 2, b Sr CH 3 COO 2 and c Sr C 2 H 5 COO 2 as a starting material. ñ íú Ý Ú CRN šð SrSi 2 O 2 N 2 Ò Ý Ò Sr 2 Si 5 N 8 Ú Ê Ú ë î œ ê ñ Ê ÙÛ p œ Ý Õ Ó ý Ú SrSi 2 O 2 N 2 ý Õ œ êñ ÝÊ p Sr é Ý Õ ý Sr CH 3 COO 2 Ý p p Sr CH 3 COO 2 SrCO 3 šý
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