An efficient and user-friendly method for the synthesis of hexagonal-phase NaYF4: Yb, Er/Tm nanocrystals with controllable shape and upconversion fluorescence
An efficient and user-friendly method for the synthesis of hexagonal-phase NaYF4: Yb, Er/Tm nanocrystals with controllable shape and upconversion fluorescence
复制标题
DOI：
10.1088/0957-4484/19/34/345606
复制
发表时间：
2008-08-27
期刊：
影响因子：
3.5
通讯作者：
Zhang, Yong
中科院分区：
文献类型：
--
作者：
Li, Zhengquan;Zhang, Yong
六方相NaYF(4)：Yb，Er/Tm纳米晶是迄今为止最好的红外-可见光上转换材料，但目前还缺乏制备具有上转换荧光的纯六方相NaYF(4)：Yb，Er/Tm纳米晶的方法。到目前为止报道的大多数方法都需要在高温反应中使用过量的氟化物反应物，这对使用者非常不友好，并引发了安全问题。在本工作中，通过形成小的固态晶核和晶核的进一步生长和成熟，开发了一种高效和用户友好的方法来合成具有上转换荧光的均匀六方相NaYF(4)：Yb，Er/Tm纳米晶。通过改变表面活性剂的浓度，还选择性地制备了NaYF(4)：Yb、Er/Tm纳米片、纳米球和纳米椭圆形。所有的纳米晶都表现出很强的上转换荧光，即使当激光功率密度降到50 mW cm(-2)左右时，也能观察到来自纳米板的荧光。这些纳米晶体在生物学和医学中作为荧光标记或成像探针具有巨大的潜力。
Hexagonal-phase NaYF(4): Yb, Er/Tm nanocrystals are the best IR-to-visible upconverting materials to date, but user-friendly methods for making pure hexagonal-phase NaYF(4): Yb, Er/Tm nanocrystals with upconversion fluorescence are still lacking. Most of the methods reported so far require excess fluoride reactants in a high-temperature reaction which are very unfriendly to users and raise safety concerns. In this work, an efficient and user-friendly method was developed for the synthesis of uniform hexagonal-phase NaYF(4): Yb, Er/Tm nanocrystals with upconversion fluorescence, by forming small solid-state crystal nuclei and further growth and ripening of the nuclei. NaYF(4): Yb, Er/Tm nanoplates, nanospheres and nanoellipses were also selectively produced by varying the concentration of the surfactant. All the nanocrystals showed strong upconversion fluorescence, and fluorescence from the nanoplates was observed even when the laser power density was reduced to about 50 mW cm(-2). These nanocrystals have great potential for use in biology and medicine as fluorescent labels or imaging probes.