Nanomechanical Systems Research Division, Korea Institute of Machinery and Materials (KIMM) , Daejeon 305-343, Korea.
J Am Chem Soc. 2014 Jun 25;136(25):8883-6. doi: 10.1021/ja503957r. Epub 2014 Jun 17.
The fast degradation of lead selenide (PbSe) nanocrystal quantum dots (NQDs) in ambient conditions impedes widespread deployment of the highly excitonic, thus versatile, colloidal NQDs. Here we report a simple in situ post-synthetic halide salt treatment that results in size-independent air stability of PbSe NQDs without significantly altering their optoelectronic characteristics. From TEM, NMR, and XPS results and DFT calculations, we propose that the unprecedented size-independent air stability of the PbSe NQDs can be attributed to the successful passivation of under-coordinated PbSe(100) facets with atomically thin PbX2 (X = Cl, Br, I) adlayers. Conductive films made of halide-treated ultrastable PbSe NQDs exhibit markedly improved air stability and behave as an n-type channel in a field-effect transistor. Our simple in situ wet-chemical passivation scheme will enable broader utilization of PbSe NQDs in ambient conditions in many optoelectronic applications.
在环境条件下，硒化铅（PbSe）纳米晶量子点（NQDs）的快速降解阻碍了高激子、多功能胶体 NQDs 的广泛应用。在这里，我们报告了一种简单的原位后合成卤化物盐处理方法，可实现 PbSe NQDs 在不显著改变其光电特性的情况下，具有尺寸独立的空气稳定性。从 TEM、NMR 和 XPS 结果以及 DFT 计算中，我们提出 PbSe NQDs 前所未有的尺寸独立的空气稳定性可归因于用原子层厚的 PbX2（X = Cl、Br、I）吸附层成功钝化配位不足的 PbSe(100)面。由经过卤化物处理的超稳定 PbSe NQDs 制成的导电膜具有明显改善的空气稳定性，并在场效应晶体管中表现为 n 型沟道。我们简单的原位湿化学钝化方案将使 PbSe NQDs 在许多光电应用中能够在环境条件下更广泛地应用。
