电荷迁移态敏化Ba_3Gd_2WO_9:Eu~(3+)红色荧光粉的光学性能
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摘要
采用高温固相法制备了一系列不同Eu~(3+)掺杂浓度的Ba_3Gd_2WO_9:Eu~(3+)红色荧光粉,并对其结构、形貌、光致发光以及电致发光特性进行了研究。结果表明:Eu~(3+)的~7F_0→~5L_6激发带坐落在O~(2–)→W~(6+)电荷迁移带的肩部,后者有效提高了395 nm处激发线宽与强度;在近紫外光激发下,~5D_0→~7F_2电偶极跃迁与~5D_0→~7F_1磁偶极跃迁强度相当,反映出Eu~(3+)同时占据具有中心和非中心对称的多个结晶学格位。根据荧光强度与掺杂浓度的变化趋势,确定出最佳Eu~(3+)掺杂量为50%(摩尔分数),并得出浓度猝灭是由Eu~(3+)间电偶极-电偶极相互作用引起;利用~5D_0–电荷迁移态共振跃迁模型分析了荧光温度猝灭行为,并计算得到热活化能为0.367 3 eV。将此荧光粉涂覆在近紫外LED芯片上,得到了性能优良的红光和白光LED灯珠。
Ba_3Gd_2WO_9:Eu~(3+) red-emitting phosphors with different Eu~(3+) contents were prepared via high-temperature solid-phase reaction.The structure, morphology, photoluminescence and electroluminescence were investigated.The ~7F_0 →~5L_6 transition of Eu~(3+)situates on the shoulder of the O~(2–)→ W~(6+) charge transfer state(CTS), while the latter enhances the excitation width and intensity at 395 nm.Upon the near-ultraviolet excitation, the emission intensity for ~5D_0 →~7F_2 electric dipole(ED) transition is comparable to that for ~5D_0 → ~7F_1 magnetic dipole(MD) transition, indicating that Eu~(3+) occupies simultaneously the crystallographic multi-sites with and without the inversion centers.The dependence of integrated intensity on Eu~(3+) contents reveals the optimal composition(Eu~(3+)-doping amount of 50% in mole fraction) and the ED–ED interaction, resulting in the concentration quenching.The thermal quenching was analyzed in the framework of ~5D_0–CTS resonance transition model, from which the activation energy(0.367 3 eV) was determined.The prototype LEDs fabricated by coating the phosphors on the near-UV chips emit a bright light.
Ba_3Gd_2WO_9:Eu~(3+) red-emitting phosphors with different Eu~(3+) contents were prepared via high-temperature solid-phase reaction.The structure, morphology, photoluminescence and electroluminescence were investigated.The ~7F_0 →~5L_6 transition of Eu~(3+)situates on the shoulder of the O~(2–)→ W~(6+) charge transfer state(CTS), while the latter enhances the excitation width and intensity at 395 nm.Upon the near-ultraviolet excitation, the emission intensity for ~5D_0 →~7F_2 electric dipole(ED) transition is comparable to that for ~5D_0 → ~7F_1 magnetic dipole(MD) transition, indicating that Eu~(3+) occupies simultaneously the crystallographic multi-sites with and without the inversion centers.The dependence of integrated intensity on Eu~(3+) contents reveals the optimal composition(Eu~(3+)-doping amount of 50% in mole fraction) and the ED–ED interaction, resulting in the concentration quenching.The thermal quenching was analyzed in the framework of ~5D_0–CTS resonance transition model, from which the activation energy(0.367 3 eV) was determined.The prototype LEDs fabricated by coating the phosphors on the near-UV chips emit a bright light.
引文
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[26]褚明辉,刘学彦,吴庆,等.高掺杂Ce,Gd(Y3-x-y CexGdy)Al5O12荧光粉的发光下降及温度猝灭特性[J].无机化学学报,2010,26(2):183-189.CHU Minghui,LIU Xueyan,WU Qing,et al.Chin J Inorg Chem(in Chinese),2010,26(2):183-189.
[27]张海明,张浩然,刘应亮,等.SiO2包覆Ca Al12O19:Mn4+荧光粉的温度特性[J].无机化学学报,2015,31(8):1489-1494.ZHANG Haiming,ZHANG Haoran,LIU Yingliang,et al.Chin J Inorg Chem(in Chinese),2015,31(8):1489-1494.
[2]LIN C C,MEIJERINK A,LIU R S.Critical red components for next-generation white LEDs[J].J Phys Chem Lett,2016,7(3):495-503.
[3]PUST P,WEILER V,HECHT C,et al.Narrow-band red-emitting Sr[LiAl3N4]:Eu2+as a next-generation LED-phosphor material[J].Nat Mater,2014,13:891-896.
[4]郑庆华,周薇薇,吕兆承,等.NaLaMgTeO6:Eu3+新型红色荧光粉的制备与发光性能[J].硅酸盐学报,2017,45(4):542-547.ZHENG Qinghua,ZHOU Weiwei,LüZhaocheng,et al.J Chin Ceram Soc,2017,45(4):542-547.
[5]ZHONG J,CHEN D,XU H,et al.Red-emitting CaLa4(SiO4)3O:Eu3+phosphor with superior thermal stability and high quantum efficiency for warm w-LEDs[J].J Alloy Compd,2017,695:311-318.
[6]LI L,LIN Y,ZHANG L,et al.Flux exploration,growth,and optical spectroscopic properties of large size LaBSiO5 and Eu3+-substituted La BSiO5 crystals[J].Cryst Growth Des,2017,17(12):6541-6549.
[7]吴迪,叶信宇,刘松彬,等.Li+掺杂对(ScLu)VO4:Eu3+红色荧光粉结构及发光性能的影响[J].硅酸盐学报,2018,46(1):1-8.WU Di,YE Xinyu,LIU Songbin,et al.J Chin Ceram Soc,2018,46(1):1-8.
[8]吕兆承,李营,全桂英,等.近紫外宽带激发LED用红色荧光粉(Gd1-x Eux)6(Te1-y Moy)O12的制备与性能[J].物理学报,2017,66(11):350-356.LüZhaocheng,LI Ying,QUAN Guiying,et al.Aata Phys Sin(in Chinese),2017,66(11):350-356.
[9]LI K,FAN J,SHANG M,et al.Sr2Y8(SiO4)6O2:Bi3+/Eu3+:Asingle-component white-emitting phosphor via energy transfer for UVw-LEDs[J].J Mater Chem C,2015,3(38):9989-9998.
[10]LI P,WANG Z,YANG Z,et al.SrIn2O4:Eu3+,Sm3+:A red emitting phosphor with a broadened near-ultraviolet absorption band for solid-state lighting[J].J Electrochem Soc,2011,158(12):H1201-H1205.
[11]ZHANG X,GONG M.Photoluminescence and energy transfer of Ce3+,Tb3+,and Eu3+doped KBaY(BO3)2 as near-ultraviolet-excited color-tunable phosphors[J].Ind Eng Chem Res,2015,54(31):7632-7639.
[12]JIAO M,YANG C,LIU M,et al.Mo6+substitution induced band structure regulation and efficient near-UV-excited red emission in Na LaMg(W,Mo)O6:Eu phosphor[J].Opt Mater Express,2017,7(7):2660-2671.
[13]DU P,YU J S.Eu3+-activated La2MoO6-La2WO6 red-emitting phosphors with ultrabroad excitation band for white light-emitting diodes[J].Sci Rep,2017,7(1):11953.
[14]DUTTA P S,KHANNA A.Eu3+activated molybdate and tungstate based red phosphors with charge transfer band in blue region[J].ECS JSolid State SC,2013,2(2):R3153-R3167.
[15]HUANG Y,SEO H J.The spectroscopy and micro-Structure of Eu3+ions doped double perovskite Ba3Y2WO9[J].J Electrochem Soc,2011,158(7):J215-J220.
[16]DONG X,FU Z,WANG Q,et al.Synthesis and investigation of luminescence properties of Eu3+-doped cubic perovskite Ba3Y2WO9[J].Opt Mater,2013,35(8):1577-1581.
[17]FONGER W H,STRUCK C W.Eu+3 5D resonance quenching to the charge-transfer states in Y2O2S,La2O2S,and LaOCl[J].J Chem Phys,1970,52(12):6364-6372.
[18]FUENTES A F,GARZA-GARCíA M,ESCALANTE-GARCíA J I,et al.Synthesis and structural characterization of Ba(LnIII2/3BVI1/3)O3(LnIII=Dy,Gd and Sm;BVI=Mo or W)complex perovskites[J].JSolid State Chem,2003,175(2):299-305.
[19]TOBY B H,VON DREELE R B.GSAS-II:the genesis of a modern open-source all purpose crystallography software package[J].J Appl Cryst,2013,46(2):544-549.
[20]TAUC J,GRIGOROVICI R,VANCU A.Optical properties and electronic structure of amorphous germanium[J].Phys Status Solid B,1966,15(2):627-637.
[21]TANNER P A.Some misconceptions concerning the electronic spectra of tri-positive europium and cerium[J].Chem Soc Rev,2013,42(12):5090-5101.
[22]BLASSE G.Energy transfer in oxidic phosphors[J].Phys Lett A,1968,28(6):444-445.
[23]黄世华.能量传递中敏化剂发光强度与浓度的关系[J].发光学报,1990,11(1):1-7.HUANG Shihua,Chin J Lumin(in Chinese),1990,11(1):1-7.
[24]BERRY M T,MAY P S,XU H.Temperature dependence of the Eu3+5D0 lifetime in europium tris(2,2,6,6-tetramethyl-3,5-heptanedionato)[J].J Phys Chem,1996,100(22):9216-9222.
[25]WEN D,FENG J,LI J,et al.K2Ln(PO4)(WO4):Tb3+,Eu3+(Ln=Y,Gd and Lu)phosphors:highly efficient pure red and tuneable emission for white light-emitting diodes[J].J Mater Chem C,2015,3(9):2107-2114.
[26]褚明辉,刘学彦,吴庆,等.高掺杂Ce,Gd(Y3-x-y CexGdy)Al5O12荧光粉的发光下降及温度猝灭特性[J].无机化学学报,2010,26(2):183-189.CHU Minghui,LIU Xueyan,WU Qing,et al.Chin J Inorg Chem(in Chinese),2010,26(2):183-189.
[27]张海明,张浩然,刘应亮,等.SiO2包覆Ca Al12O19:Mn4+荧光粉的温度特性[J].无机化学学报,2015,31(8):1489-1494.ZHANG Haiming,ZHANG Haoran,LIU Yingliang,et al.Chin J Inorg Chem(in Chinese),2015,31(8):1489-1494.