论文标题
溶液中PBS纳米晶体配体壳的结构，柔软度和动力学的中子散射透视
A Neutron Scattering Perspective on the Structure, Softness and Dynamics of the Ligand Shell of PbS Nanocrystals in Solution
论文作者
论文摘要
小角度中子和X射线散射，中子反向散射和中子飞行时间光谱法被应用以揭示配体壳的结构，依赖温度的扩散性能以及PBS纳米晶的声子频谱在脱硫的六烷中与油酸官能化。用油酸和解吸配体分子装饰的纳米晶体表现出简单的布朗散发，具有stokes-内斯坦温度依赖性并抑制冷冻。从表面解吸的配体分子显示出强烈的空间限制。吸附到纳米晶体表面的油酸的声子光谱表现出与主要的Pb-character的混合模式。 NC的低能表面模式是突出的，表明溶液中的机械柔软度很大。这项工作为溶液中胶体纳米晶体的配体粒子相互作用提供了全面的见解，并突出了其对扩散和振动特性及其机械柔软性的影响。
Small-angle neutron and X-ray scattering, neutron backscattering and neutron time-of-flight spectroscopy are applied to reveal the structure of the ligand shell, the temperature-dependent diffusion properties and the phonon spectrum of PbS nanocrystals functionalized with oleic acid in deuterated hexane. The nanocrystals decorated with oleic acid as well as the desorbed ligand molecules exhibit simple Brownian diffusion with a Stokes-Einstein temperature-dependence and inhibited freezing. Ligand molecules desorbed from the surface show strong spatial confinement. The phonon spectrum of oleic acid adsorbed to the nanocrystal surface exhibits hybrid modes with a predominant Pb-character. Low-energy surface modes of the NCs are prominent and indicate a large mechanical softness in solution. This work provides comprehensive insights into the ligand-particle interaction of colloidal nanocrystals in solution and highlights its effect on the diffusion and vibrational properties as well as their mechanical softness.
