NUV/blue LED excitable intense green emitting terbium doped lanthanum molybdate nanophosphors for white LED applications
NUV/blue LED excitable intense green emitting terbium doped lanthanum molybdate nanophosphors for white LED applications
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DOI：
10.1007/s10854-017-7708-6
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发表时间：
2017-08
期刊：
影响因子：
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通讯作者：
Kukku Thomas;D. Alexander;S. Sisira;P. Biju;N. Unnikrishnan;M. A. Ittyachen;C. Joseph
中科院分区：
文献类型：
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作者：
Kukku Thomas;D. Alexander;S. Sisira;P. Biju;N. Unnikrishnan;M. A. Ittyachen;C. Joseph
采用共沉淀法成功地合成了掺铽镧氧化物（La 2 −xTbx（MoO 4）3）纳米晶。粉末X射线衍射分析表明，纳米晶为四方晶系，空间群为I41/a。FTIR光谱确定了特征振动模式。TEM分析揭示了在没有任何形状调节催化剂的帮助下，通过平均直径为50 nm的纳米颗粒的定向附着形成的长度为90-350 nm的细长纳米棒状结构。纳米荧光粉在NUV区沿着强烈的宽电荷转移带，并在蓝光区具有Tb 3+离子的尖锐激发峰，表明该材料适合于NUV和蓝光LED照明应用。激发光谱中的电荷转移带随着Tb 3+掺杂浓度的增强而增强，表明从宿主晶格到Tb 3+离子的能量转移的可能性。在545 nm处的有效绿色发射，在电荷转移带（287 nm）中激发清楚地证明了从主体到Tb 3+离子的优异的能量转移。具有所需色度坐标和高色纯度的强绿色发射使得掺铽镧纳米晶体作为用于NUV/蓝光LED激发的WLED的高效绿色磷光体。
Terbium doped lanthanum molybdate (La2−xTbx(MoO4)3) nanocrystals were successfully synthesized by facile co-precipitation method. The powder X-ray diffractogram confirmed that the nanocrystals were crystallized in tetragonal phase with space group I41/a. The FTIR spectra identified the characteristic vibrational modes. The TEM analysis revealed elongated nanorod like structures of length 90–350 nm formed by oriented attachment of nanoparticles of average diameter 50 nm without the aid of any shape regulating catalysts. The intense broad charge transfer band in NUV region along with sharp excitation peaks of Tb3+ions in the blue region of photoluminescence excitation spectra ascertains that the prepared nanophosphors are suitable materials for NUV and blue LED based lighting applications. The possibility of energy transfer from host lattice to Tb3+ions is indicated by the enhancement of charge transfer band with Tb3+doping concentration in the excitation spectrum. The efficient green emission at 545 nm, on exciting in the charge transfer band (287 nm) clearly evidenced the excellent energy transfer from host to Tb3+ions. The intense green emission with desirable chromaticity co-ordinates and high colour purity makes Terbium doped lanthanum molybdate nanocrystals as an efficient green phosphor for NUV/blue LED excited WLED.