采用微乳液-水热结合法制备了NaYF4∶Yb3+, Er3+, Tm3+纳米粒子, 利用Ｘ射线衍射（XRD）、 扫描电镜（SEM）等手段对样品的物相、 结构和形貌进行了分析与表征。 产物的X射线衍射峰与标准卡片PDF #77-2042完全一致, 属于立方相NaYF4; SEM图片显示所制备的纳米粒子形貌和粒径都比较均一, 为120 nm左右的棉花状小球, 由纳米微粒聚集而成; 在980 nm光的激发下, 纳米粒子能够同时发出蓝光（438和486 nm）、 绿光（523和539 nm）和红光（650 nm）; 通过调节Tm3+∶Er3+的比例（0, 0.5, 0.8, 1, 2, 3, 5, 7）, 由色度坐标图（CIE）可以看出当Tm3+和Er3+的比例从0增加到2时, 样品的整体发光光色是向绿光方向移动; 当Tm3+和Er3+的比例为1∶1时, 得到伪白光; Tm3+和Er3+的比例从2到7时, 样品整体的发光向红光方向移动。

NaYF4∶Yb3+, Er3+, Tm3+ nanoparticles were prepared by microemulsion-hydrothermal method. Crystal phase, morphology and structure of the samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The luminescence properties were studied by up-conversional fluorescence spectroscopy. The XRD patterns of as-prepared samples were in agreement with the PDF #77-2042 of cubic NaYF4. SEM images of the particles showed that the samples were cotton-like spherical in shape and which were assembled by smaller nano-particles. The average size was 120 nm, while the shape was regular and the particle size was homogeneous. Under the excitation of 980 nm, the as-prepared particles could emit blue (438 and 486 nm), green (523 and 539 nm) and red (650 nm) light simultaneously. It can be seen from the color coordinates figure (CIE) that when doping concentration ratio of Tm3+ and Er3+ increased from 0 to 2, the whole emitting light color of samples movedto green region. While the ratio was 1∶1, pseudo white light was obtained. As the ratio changed from 2 to 7, the luminous color was moved to red region.