摘要： Bottom-up fabrication of thermoelectric (TE) materials from colloidal nanocrystal (NC) building blocks can substantially increase their TE efficiency, e.g., by reducing lattice thermal conductivity. In this work, 10-nm spherical phase-pure oleate-capped PbTe NCs with narrow size distribution were synthesized and employed to fabricate 50-nm thick films on insulating SiO2/Si substrates. The spin-coating, with subsequent ligand exchange procedure, was applied to enhance coupling interactions between the NCs. Using dark conductivity measurements, we confirmed the semiconducting behavior and the Schottky-type electrical field-dependent conductivity mechanism in the resultant thin films. The thermal transport in the thin-film was probed by means of a time-domain thermoreflectance (TDTR) method. For this purpose, we used a customized state-of-the-art system based on a picosecond thermoreflectance instrument, which enables area-selective analysis with spatial resolution down to 5 μm. The results show that as-fabricated PbTe NC films exhibit ultralow thermal conductivity of 0.9 W m–1 K–1 at 300 K. The transport property findings suggest potential in the proposed quick and cost-effective spin-coating strategy for bottom-up fabrication of nanostructured TE films from high-quality colloidal NC building blocks.