中文摘要：

采用油相合成法得到了疏水性、单分散的LaPO4∶Ce3＋,LaPO4∶Ce3＋/LaPO4和LaPO4∶Ce3＋/LaPO4∶Ce3＋/LaPO4核壳结构纳米晶。利用X射线衍射（XRD）、透射电镜（TEM）、傅里叶变换红外光谱（FTIR）和光致发光光谱（PL）等分析技术对产物的结构、形貌以及发光性能进行了表征。结果表明：所有样品均为单斜相结构,样品的衍射峰呈现宽化现象,可能由于合成的纳米颗粒尺寸较小;Ce3＋掺杂LaPO4纳米晶显示了Ce3＋的特征发射,在342nm处是一个宽带谱,发光强度随着Ce3＋掺杂浓度的增加先增加后减小,在浓度为6at%时发光强度最大,发光强度减弱可能由于浓度猝灭导致的;LaPO4∶Ce3＋/LaPO4和LaPO4∶Ce3＋/LaPO4∶Ce3＋/LaPO4核壳结构纳米晶光致发光强度比LaPO4∶Ce3＋纳米颗粒分别提高了41%和95%左右,这可能是由于纳米晶颗粒尺寸的变大及表面钝化效应共同作用的结果;样品的红外光谱数据显示,在1 545和1 461cm-1处出现了分别对应于—COO-的非对称和对称伸缩振动的两个吸收峰,这两个峰的间隔为84cm-1,样品表面有机物的修饰机制可能是羧基的氧原子以双齿模式与金属镧离子发生了配位。

英文摘要：

Hydrophobic,monodisperse LaPO4∶Ce3＋nanoparticles,LaPO4∶Ce3＋/LaPO4 and LaPO4∶Ce3＋/LaPO4∶Ce3＋/LaPO4core/shell structure nanocrystals were synthesized via a high-temperature organic solution approach.The as-synthesized samples were characterized by X-ray diffraction（XRD）,transmission electron microscopy（TEM）,Fourier transform infrared spectroscopy（FTIR）and photoluminescence spectroscopy（PL）.The results show that：all the samples are a monoclinic phase,Because of the size small nanoparticles,the diffraction peaks of the sample occurs width phenomenon.The LaPO4∶Ce3＋nanocrystals exhibits the characteristic emission of Ce3＋ions,the photoluminescence intensity increases first and then decreases with the increasing doping concentration of Ce3＋ions,and the best doping amount is 6at%,with the increasing doping amount,the photoluminescence intensity decreases which may caused by the concentration quenching.Compared to LaPO4∶Ce3＋nanoparticles,the photoluminescence intensity of LaPO4 ∶Ce3＋/LaPO4 and LaPO4 ∶Ce3＋/LaPO4∶Ce3＋/LaPO4core/shell structure nanocrystals improves about 41% and 95%respectively,this may be a synergy of larger particle size of nanocrystals and surface passivation effect.FTIR spectra data shows that the absorption peak at 1 545 and 1 461cm-1 corresponded to the asymmetric and symmetric stretching vibration of—COO-,the separation,Δ,between the two peaks is 84cm-1,The mechanism of the sample surface modification by the organics might be that the oxygen atoms of the carboxyl are coordinated with the lanthunum ions by a bidentate mode.