The adsorption, self-organization and oriented attachment of PbSe nanocrystals (NCs) at liquid-air interfaces has led to remarkable nanocrystal superlattices with atomic order and a superimposed nanoscale geometry. Earlier studies examined the NC self-organization at the suspension/air interface with time-resolved in-situ X-ray scattering. Upon continuous evaporation of the solvent, the NC interfacial layer will finally contact the (ethylene glycol) liquid substrate on which the suspension was casted. In order to obtain structural information on the NC organization at this stage of the process, we examined the ethylene glycol/NC interface in detail for PbSe NCs of different sizes, combining in-situ grazing-incidence small-and-wide-angle X-ray scattering (GISAXS/GIWAXS), X-ray reflectivity (XRR) and analytical calculations of the adsorption geometry of these NCs. Here, we observe in-situ three characteristic adsorption geometries varying with the NC size. Based on the experimental evidence and simulations, we reveal fully three-dimensional arrangements of PbSe nanocrystals at the ethylene glycol-air interface with and without the presence of rest amounts of toluene.

PbSe 纳米晶体 (NCs) 在液-气界面的吸附、自组织和定向附着导致了具有原子序和叠加纳米级几何结构的显着纳米晶体超晶格。早期的研究使用时间分辨原位 X 射线散射检查了悬浮液/空气界面处的 NC 自组织。在溶剂连续蒸发后，NC 界面层将最终接触悬浮液浇铸在其上的（乙二醇）液体基质。为了在此过程的这个阶段获得有关 NC 组织的结构信息，我们详细检查了不同尺寸的 PbSe NC 的乙二醇/NC 界面，结合原位掠入射小和广角 X-射线散射 (GISAXS/GIWAXS)，X 射线反射率 (XRR) 和这些 NC 的吸附几何结构的分析计算。在这里，我们观察到随 NC 尺寸变化的原位三种特征吸附几何形状。基于实验证据和模拟，我们揭示了在存在和不存在剩余量甲苯的情况下乙二醇-空气界面处 PbSe 纳米晶体的完全三维排列。