在发光二极管背光源上极具应用前景的Beta-sialon(Si_(6-z)Al_zO_zN_(8-z))∶Eu~(2+)窄带绿色荧光粉（英文）
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摘要
基于氮化镓的白光发光二极管(LED)是目前一项崭新的背光源技术,广泛应用于宽色域、高光效的液晶显示屏。在此项技术中,作为关键材料的荧光粉决定着背光单元的色域范围、发光效率和可靠性,因而要求它应具合适的发射波长和窄带发射。β-sialon∶Eu~(2+)(sialon:silicon aluminum oxynitride(赛龙))就是一款非常适合背光应用的绿色荧光粉,这得益于其位于525~545 nm发射峰和只有55 nm狭窄的峰宽。此文回顾和综述了β-sialon∶Eu~(2+)的合成方法、光谱特性、电子结构、晶体结构、可靠性和它的具体应用。计算模拟和实验测试结果表明,Eu~(2+)位于沿c轴方向的大孔道之中,并与6个最紧邻的(O,N)原子等距离配位。因而,Eu~(2+)的狭窄发射峰源自于Eu~(2+)局域结构的高度对称性。β-sialon∶Eu~(2+)的发射波长和带宽都能通过组成裁剪,即z值,进行调控;低z值组成能够实现更短波长发射和更窄带宽。与传统的基于钇铝石榴石(YAG)荧光粉的背光源相比,β-sialon∶Eu~(2+)再搭配红色荧光粉制备的背光源具有更宽的色域,色域范围可提高15%以上。其优异的发光性能和高可靠性使得β-sialon∶Eu~(2+)成为应用于先进显示屏的极其重要的绿色发光材料。
GaN-based white light-emitting diode( LED) is now an emerging backlight technology for large color gamut and high efficiency liquid crystal displays. In this technology,phosphors are key materials to control the color-space coverage,luminous efficiency,and lifetime of the backlight units,which are required to have a desired emission and a narrow emission band. β-Sialon ∶ Eu~(2+)( sialon: silicon aluminum oxynitride,Si_(6-z)Al_zO_zN_(8-z)) is such a green phosphor because it has an emission band centered at 525 ~ 545 nm and a small band width( ~ 55 nm). This contribution overviews the synthesis,luminescence,electronic and crystal structure,reliability and applications ofβ-sialon∶ Eu~(2+). From both structure calculations and experimental observations,Eu~(2+)is seen to be accommodated into a large void along the c-axis,and coordinated to six nitrogen / oxygen atoms at an equivalent distance. The narrow emission band is thus ascribed to the high symmetry of the local structure of Eu~(2+). Both of the emission band and the band width of β-sialon∶ Eu~(2+)can be tuned by tailoring the composition( e. g.,the z value),and β-sialon∶ Eu~(2+)with shorter wavelengths and narrower bands can be achieved at lower z values. Combined with other red phosphors,β-sialon∶ Eu~(2+)enables to produce wider color gamut backlights( 15% up) than the conventional yttrium aluminum garnet( YAG)-based ones. Both the excellent luminescence properties and reliability make β-sialon ∶ Eu~(2+)to be an extremely important green phosphor for use in advanced displays.
GaN-based white light-emitting diode( LED) is now an emerging backlight technology for large color gamut and high efficiency liquid crystal displays. In this technology,phosphors are key materials to control the color-space coverage,luminous efficiency,and lifetime of the backlight units,which are required to have a desired emission and a narrow emission band. β-Sialon ∶ Eu~(2+)( sialon: silicon aluminum oxynitride,Si_(6-z)Al_zO_zN_(8-z)) is such a green phosphor because it has an emission band centered at 525 ~ 545 nm and a small band width( ~ 55 nm). This contribution overviews the synthesis,luminescence,electronic and crystal structure,reliability and applications ofβ-sialon∶ Eu~(2+). From both structure calculations and experimental observations,Eu~(2+)is seen to be accommodated into a large void along the c-axis,and coordinated to six nitrogen / oxygen atoms at an equivalent distance. The narrow emission band is thus ascribed to the high symmetry of the local structure of Eu~(2+). Both of the emission band and the band width of β-sialon∶ Eu~(2+)can be tuned by tailoring the composition( e. g.,the z value),and β-sialon∶ Eu~(2+)with shorter wavelengths and narrower bands can be achieved at lower z values. Combined with other red phosphors,β-sialon∶ Eu~(2+)enables to produce wider color gamut backlights( 15% up) than the conventional yttrium aluminum garnet( YAG)-based ones. Both the excellent luminescence properties and reliability make β-sialon ∶ Eu~(2+)to be an extremely important green phosphor for use in advanced displays.
引文
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[4]Luo Z,Chen Y,Wu S T.Wide Color Gamut LCD with a Quantum Dot Backlight[J].Opt Express,2013,21(22):26269-26284.
[5]Ito Y,Hori T,Kusunoki T,et al.A Phosphor Sheet and a Backlight System Providing Wider Color Gamut for LCDs[J].J Soc Inf Display,2014,22(8):419-428.
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[8]Shirasaki Y,Supran G J,Bawendi M G,et al.Emergence of Colloidal Quantum-dot Light-emitting Technologies[J].Nat Photon,2013,7(1):13-23.
[9]Coe-Sullivan S,Liu W,Allen P,et al.Quantum Dots for LED Downconversion in Display Applications[J].ECS J Solid State Sci Technol,2013,2(2):R3026-R3030.
[10]Fukuda Y,Ishida K,Mitsuishi I,et al.Luminescence Properties of Eu2+-doped Green-emitting Sr-Sialon Phosphor and Its Application to White Light-emitting Diodes[J].Appl Phys Express,2009,2(1):012401-1-012401-3.
[11]Hirosaki N,Xie R J,Kimoto K,et al.Characterization and Properties of Green-emittingβ-SiA lO N∶Eu2+Powder Phosphors for White Light-emitting Diodes[J].Appl Phys Lett,2005,86(21):211905-1-211905-3.
[12]Xie R J,Hirosaki N,Li H L,et al.Synthesis and Photoluminescence Properties ofβ-Sialon∶Eu2+(Si6-zAlzOzN8-z∶Eu2+):A Promising Green Oxynitride Phosphor for White Light-emitting Diodes[J].J Electrochem Soc,2007,154(10):J314-J319.
[13]Munir Z A.Synthesis of High Temperature Materials by Self-propagating Combustion Methods[J].Am Ceram Soc Bull,1988,67(2):342-349.
[14]Zhou Y,Yoshizawa Y,Hirao K,et al.Preparation of Eu-dopedβ-SiA lO N Phosphors by Combustion Synthesis[J].J Am Ceram Soc,2008,91(9):3082-3085.
[15]Xu K,He G,Liu G,et al.Combustion Synthesis of Eu2+Dopedβ-SiA lO N Phosphors by Salt Assistance[J].ECS J Solid State Sci Technol,2013,2(11):R230-R232.
[16]Niu J,Saito G,Akiyama T.A New Route to Synthesizeβ-SiA lO N∶Eu2+Phosphors for White Light-emitting Diodes[J].Appl Phys Express,2013,6(4):0421059-1-0421059-3.
[17]Yan Q,Liu Q,Liu Q F.Synthesis of Rod-like High-purityβ-Sialon Powder by a Novel Carbothermal Reduction-nitridation Method with a Nanocasting Procedure[J].J Am Ceram Soc,2010,93(9):2470-2471.
[18]Jun K,Lee K,Kim G,et al.A new Route for the Synthesis ofβ-Sialon Phosphors Using Pyrophyllite Powders[J].Ceram Int,2013,39(1):S349-S353.
[19]Bernardo E,Parcianello G,Pilati S,et al.Novel Synthesis of Eu-doped SiA lO N Luminescent Materials from a Preceramic Polymer and Nano-sized Fillers[J].J Asian Ceram Soc,2014,2(2):158-164.
[20]Xie R J,Hirosaki N,Mitomo M,et al.Optical Properties of Eu2+inα-SiA lO N[J].J Phys Chem B,2004,108(32):12027-12031.
[21]Van Krevel J W H,Hintzen H T,Metselaar R,et al.Long Wavelength Ce3+Emission in Y-Si-O-N Materials[J].J Alloys Compds,1998,268(1/2):272-277.
[22]Boyko T D,Gross T,Schwarz Z M,et al.The Local Crystal Structure and Electronic Band Gap ofβ-Sialons[J].J Mater Sci,2014,49(8):3242-3252.
[23]Takahashi K,Xie R J,Hirosaki N.Toward Higher Color Purity and Narrower Emission Bandβ-Sialon∶Eu2+by Reducing the Oxygen Concentration[J].Electrochem Solid State Lett,2011,14(11):E38-E40.
[24]Takase A,Umebayashi S,Kishi K.Infra-red Absorption Spectroscopic Study ofβ-Sialons in the System Si3N4-Al2O3·AlN[J].Jpn J Appl Phys,1982,21(10):1447-1450.
[25]Li Y Q,Hirosaki N,Xie R J,et al.Crystal and Electronic Structure,Luminescence Properties of Eu2+-doped Si6-zAlzOzN8-zand MySi6-zAlz-yOz+yN8-z-y(M=2Li,Mg,Ca,Sr,Ba)[J].J Solid State Chem,2008,181:3200-3210.
[26]Yoo D S,Ryu J H,Park H L,et al.Atomic and Electronic Structure Investigation and Luminescene Property of Eu2+-dopedβ-Sialon Green Phosphor:Ab initio Calculations[J].Jpn J Appl Phys,2010,49(65):06GJ07.
[27]Kimoto K,Xie R J,Matsui Y,et al.Direct Observation of Sinigle Dopant Atom in Light-emitting Phosphor ofβ-SiA lO N∶Eu2+[J].Appl Phys Lett,2009,94:041908-1-041908-3.
[28]Brgoch J,Gaultois M W,Balasubramanian M,et al.Local Structure and Structtural Rigidity of the Green Phosphorβ-SiA lO N∶Eu2+[J].Appl Phys Lett,2014,105:181904-1-181904-3.
[29]Xie R J,Li Y Q,Hirosaki N,et al.Nitride Phosphors and Solid State Lighting[M].CRC Press,2011.
[30]Yamada S,Emoto H,Ibukiyama M,et al.Properties of SiA lO N Powder Phosphors for White LEDs[J].J Euro Ceram Soc,2012,32(7):1355-1358.
[31]Wang L,Wang X J,Takahashi K,et al.Highly Efficient Narrow-band Green and Red Phosphors Enabling Wider Colorgamut LED Backlight for More Brilliant Displays[J].Opt Express,2015,23(22):28707-28717.
[2]Jang E,Jun S,Jang H,et al.White-light-emitting Diodes with Quantum Dot Color Converters for Display Backlights[J].Adv Mater,2010,22(28):3076-3080.
[3]Fukuda Y,Matsuda N,Okada A,et al.White Light-emitting Diodes for Wide-color-gamut Backlight Using Green-emitting Sr-Sialon Phosphor[J].Jpn J Appl Phys,2012,51(12R):122101-1-122101-3.
[4]Luo Z,Chen Y,Wu S T.Wide Color Gamut LCD with a Quantum Dot Backlight[J].Opt Express,2013,21(22):26269-26284.
[5]Ito Y,Hori T,Kusunoki T,et al.A Phosphor Sheet and a Backlight System Providing Wider Color Gamut for LCDs[J].J Soc Inf Display,2014,22(8):419-428.
[6]Lee S H,Lee K H,Jo J H,et al.Remote-type,High-color Gamut White Light-emitting Diode Based on InP Quantum Dot Color Converters[J].Opt Mater Express,2014,4(7):1297-1302.
[7]Oh J H,Kang H,Ko M,et al.Analysis of Wide Color Gamut of Green/Red Bilayered Freestanding Phosphor Film-capped White LEDs for LCD Backlight[J].Opt Express,2015,23(15):A791-A804.
[8]Shirasaki Y,Supran G J,Bawendi M G,et al.Emergence of Colloidal Quantum-dot Light-emitting Technologies[J].Nat Photon,2013,7(1):13-23.
[9]Coe-Sullivan S,Liu W,Allen P,et al.Quantum Dots for LED Downconversion in Display Applications[J].ECS J Solid State Sci Technol,2013,2(2):R3026-R3030.
[10]Fukuda Y,Ishida K,Mitsuishi I,et al.Luminescence Properties of Eu2+-doped Green-emitting Sr-Sialon Phosphor and Its Application to White Light-emitting Diodes[J].Appl Phys Express,2009,2(1):012401-1-012401-3.
[11]Hirosaki N,Xie R J,Kimoto K,et al.Characterization and Properties of Green-emittingβ-SiA lO N∶Eu2+Powder Phosphors for White Light-emitting Diodes[J].Appl Phys Lett,2005,86(21):211905-1-211905-3.
[12]Xie R J,Hirosaki N,Li H L,et al.Synthesis and Photoluminescence Properties ofβ-Sialon∶Eu2+(Si6-zAlzOzN8-z∶Eu2+):A Promising Green Oxynitride Phosphor for White Light-emitting Diodes[J].J Electrochem Soc,2007,154(10):J314-J319.
[13]Munir Z A.Synthesis of High Temperature Materials by Self-propagating Combustion Methods[J].Am Ceram Soc Bull,1988,67(2):342-349.
[14]Zhou Y,Yoshizawa Y,Hirao K,et al.Preparation of Eu-dopedβ-SiA lO N Phosphors by Combustion Synthesis[J].J Am Ceram Soc,2008,91(9):3082-3085.
[15]Xu K,He G,Liu G,et al.Combustion Synthesis of Eu2+Dopedβ-SiA lO N Phosphors by Salt Assistance[J].ECS J Solid State Sci Technol,2013,2(11):R230-R232.
[16]Niu J,Saito G,Akiyama T.A New Route to Synthesizeβ-SiA lO N∶Eu2+Phosphors for White Light-emitting Diodes[J].Appl Phys Express,2013,6(4):0421059-1-0421059-3.
[17]Yan Q,Liu Q,Liu Q F.Synthesis of Rod-like High-purityβ-Sialon Powder by a Novel Carbothermal Reduction-nitridation Method with a Nanocasting Procedure[J].J Am Ceram Soc,2010,93(9):2470-2471.
[18]Jun K,Lee K,Kim G,et al.A new Route for the Synthesis ofβ-Sialon Phosphors Using Pyrophyllite Powders[J].Ceram Int,2013,39(1):S349-S353.
[19]Bernardo E,Parcianello G,Pilati S,et al.Novel Synthesis of Eu-doped SiA lO N Luminescent Materials from a Preceramic Polymer and Nano-sized Fillers[J].J Asian Ceram Soc,2014,2(2):158-164.
[20]Xie R J,Hirosaki N,Mitomo M,et al.Optical Properties of Eu2+inα-SiA lO N[J].J Phys Chem B,2004,108(32):12027-12031.
[21]Van Krevel J W H,Hintzen H T,Metselaar R,et al.Long Wavelength Ce3+Emission in Y-Si-O-N Materials[J].J Alloys Compds,1998,268(1/2):272-277.
[22]Boyko T D,Gross T,Schwarz Z M,et al.The Local Crystal Structure and Electronic Band Gap ofβ-Sialons[J].J Mater Sci,2014,49(8):3242-3252.
[23]Takahashi K,Xie R J,Hirosaki N.Toward Higher Color Purity and Narrower Emission Bandβ-Sialon∶Eu2+by Reducing the Oxygen Concentration[J].Electrochem Solid State Lett,2011,14(11):E38-E40.
[24]Takase A,Umebayashi S,Kishi K.Infra-red Absorption Spectroscopic Study ofβ-Sialons in the System Si3N4-Al2O3·AlN[J].Jpn J Appl Phys,1982,21(10):1447-1450.
[25]Li Y Q,Hirosaki N,Xie R J,et al.Crystal and Electronic Structure,Luminescence Properties of Eu2+-doped Si6-zAlzOzN8-zand MySi6-zAlz-yOz+yN8-z-y(M=2Li,Mg,Ca,Sr,Ba)[J].J Solid State Chem,2008,181:3200-3210.
[26]Yoo D S,Ryu J H,Park H L,et al.Atomic and Electronic Structure Investigation and Luminescene Property of Eu2+-dopedβ-Sialon Green Phosphor:Ab initio Calculations[J].Jpn J Appl Phys,2010,49(65):06GJ07.
[27]Kimoto K,Xie R J,Matsui Y,et al.Direct Observation of Sinigle Dopant Atom in Light-emitting Phosphor ofβ-SiA lO N∶Eu2+[J].Appl Phys Lett,2009,94:041908-1-041908-3.
[28]Brgoch J,Gaultois M W,Balasubramanian M,et al.Local Structure and Structtural Rigidity of the Green Phosphorβ-SiA lO N∶Eu2+[J].Appl Phys Lett,2014,105:181904-1-181904-3.
[29]Xie R J,Li Y Q,Hirosaki N,et al.Nitride Phosphors and Solid State Lighting[M].CRC Press,2011.
[30]Yamada S,Emoto H,Ibukiyama M,et al.Properties of SiA lO N Powder Phosphors for White LEDs[J].J Euro Ceram Soc,2012,32(7):1355-1358.
[31]Wang L,Wang X J,Takahashi K,et al.Highly Efficient Narrow-band Green and Red Phosphors Enabling Wider Colorgamut LED Backlight for More Brilliant Displays[J].Opt Express,2015,23(22):28707-28717.