Phase transfer of 1-and 2-dimensional Cd-based nanocrystals
Phase transfer of 1-and 2-dimensional Cd-based nanocrystals
复制标题
DOI：
10.1039/c5nr06221g
复制
发表时间：
2015-01-01
期刊：
影响因子：
6.7
通讯作者：
Dorfs, Dirk
中科院分区：
文献类型：
--
作者：
Kodanek, Torben;Banbela, Hadeel M.;Dorfs, Dirk
在这项工作中，发光的CdSe@CdS点棒纳米晶体、CdSe@CdS/ZnS纳米棒以及CdSe-CdS核冠纳米片通过配体交换反应转移到水相中。为此，采用双功能硫醇基配体，即巯基乙酸（MAA）、3-巯基丙酸（MPA）、11-巯基十一烷酸（MUA）以及2-（二甲氨基）乙硫醇（DMAET）。通过光致发光量子产率测量以及光致发光衰减测量进行的系统研究表明，转移的纳米结构的发光特性受到空穴陷阱（由硫醇配体本身诱导）以及空间绝缘和环境钝化的影响。然而，纳米棒尖端对发光的影响是微不足道的。因此，不同的配体对于不同的纳米粒子样品产生最佳结果，这主要取决于各个样品的无机钝化。对于 CdSe@CdS 纳米棒，通过使用短链配体进行转移获得了最高的发射强度，保留了疏水性纳米棒原始量子产率的 50% 以上。与此相反，CdSe@CdS/ZnS 纳米棒的最佳量子效率是通过 MUA 实现的。所获得的知识可用于首次将二维 CdSe-CdS 核冠纳米片转移到水中，同时保持显着的光致发光（高达 12% 的量子效率）。
In this work, luminescent CdSe@CdS dot-in-rod nanocrystals, CdSe@CdS/ZnS nanorods as well as CdSe-CdS core-crown nanoplatelets were transferred into aqueous phase via ligand exchange reactions. For this purpose, bifunctional thiol-based ligands were employed, namely mercaptoacetic acid (MAA), 3-mercaptopropionic acid (MPA), 11-mercaptoundecanoic acid (MUA) as well as 2-(dimethylamino)ethanthiol (DMAET). Systematic investigations by means of photoluminescence quantum yield measurements as well as photoluminescence decay measurements have shown that the luminescence properties of the transferred nanostructures are affected by hole traps (induced by the thiol ligands themselves) as well as by spatial insulation and passivation against the environment. The influence of the tips of the nanorods on the luminescence is, however, insignificant. Accordingly, different ligands yield optimum results for different nanoparticle samples, mainly depending on the inorganic passivation of the respective samples. In case of CdSe@CdS nanorods, the highest emission intensities have been obtained by using short-chain ligands for the transfer preserving more than 50% of the pristine quantum yield of the hydrophobic nanorods. As opposed to this, the best possible quantum efficiency for the CdSe@CdS/ZnS nanorods has been achieved via MUA. The gained knowledge could be applied to transfer for the first time 2-dimensional CdSe-CdS core-crown nanoplatelets into water while preserving significant photoluminescence (up to 12% quantum efficiency).