Sizing Curve, Absorption Coefficient, Surface Chemistry, and Aliphatic Chain Structure of PbTe Nanocrystals
Sizing Curve, Absorption Coefficient, Surface Chemistry, and Aliphatic Chain Structure of PbTe Nanocrystals
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DOI：
10.1021/acs.chemmater.8b05050
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发表时间：
2019-03-12
影响因子：
8.6
通讯作者：
Vanmaekelbergh, Daniel
中科院分区：
文献类型：
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作者：
Peters, Joep L.;de Wit, Jur;Vanmaekelbergh, Daniel
对于胶体半导体纳米晶(NCS)来说，从实用和基础的角度来看，了解其化学结构和尺寸相关的光学性质是至关重要的。在这里，我们报告了PbTe NCS的基本性质，以补充已有的关于PbS和PbSe NCS的知识。用透射电子显微镜和吸收光谱相结合的方法测定了带隙与纳米管直径(尺寸)的关系曲线，一次光吸收的能量与纳米管的直径成1/d关系。用电感耦合等离子体发射光谱仪测定了NCS中的铅含量，用能量色散X射线光谱仪测定了NCS中的相对碲含量。综合这些结果，得到了内禀吸收系数的关系式，该关系式在3.1 eV时与纳米管的尺寸无关。PbTe NCS由油酸铅(2)稳定，但与PbS NCS不同的是，油酸主要以双齿配位的形式结合。此外，我们还分析了所有硫系铅化物NCS上的脂肪链的结构，结果表明，脂肪链在靠近核的位置部分是结晶的，在溶剂侧则是更多的液体状。
For colloidal semiconductor nanocrystals (NCs), the knowledge of the chemical structure and the size-dependent optical properties is of crucial importance, both from a practical and fundamental perspective. Here, we report the basic properties of PbTe NCs in order to complement the already existing knowledge on PbS and PbSe NCs. The band gap versus NC diameter (sizing) curve was determined by combining transmission electron microscopy with absorption spectroscopy; the energy of the primary optical absorption follows 1/d dependence with the diameter. The lead content of the NCs was determined with inductive coupled plasma optical emission spectrometry and the relative tellurium content with energy-dispersive X-ray spectroscopy. Combining these results yields a relation for the intrinsic absorption coefficient, which is independent of the NC size at 3.1 eV. The PbTe NCs are stabilized by Pb(oleate)(2), but different from PbS NCs, oleate is predominantly bound in a chelating bidentate coordination. Besides that, we analyzed the structure of the aliphatic chains on all lead chalcogenide NCs and showed that the aliphatic chains are partly crystalline near the core and more liquid-like at the solvent side.