ITMO University , 49 Kronverkskiy prospect, Saint-Petersburg 197101, Russia.
Langmuir. 2015 Jan 13;31(1):506-13. doi: 10.1021/la503913z. Epub 2015 Jan 2.
X-ray structural analysis, together with steady-state and transient optical spectroscopy, is used for studying the morphology and optical properties of quantum dot superlattices (QDSLs) formed on glass substrates by the self-organization of PbS quantum dots with a variety of surface ligands. The diameter of the PbS QDs varies from 2.8 to 8.9 nm. The QDSL's period is proportional to the dot diameter, increasing slightly with dot size due to the increase in ligand layer thickness. Removal of the ligands has a number of effects on the morphology of QDSLs formed from the dots of different sizes: for small QDs the reduction in the amount of ligands obstructs the self-organization process, impairing the ordering of the QDSLs, while for large QDs the ordering of the superlattice structure is improved, with an interdot distance as low as 0.4 nm allowing rapid charge carrier transport through the QDSLs. QDSL formation does not induce significant changes to the absorption and photoluminescence spectra of the QDs. However, the luminescence decay time is reduced dramatically, due to the appearance of nonradiative relaxation channels.
X 射线结构分析与稳态和瞬态光学光谱学一起，用于研究在玻璃衬底上通过具有各种表面配体的 PbS 量子点自组织形成的量子点超晶格（QDSL）的形态和光学性质。PbS QD 的直径从 2.8nm 到 8.9nm 不等。QDSL 的周期与点的直径成正比，由于配体层厚度的增加，其略有增加。配体的去除对由不同尺寸的点形成的 QDSL 的形态有多种影响：对于小 QD，配体的减少会阻碍自组织过程，从而损害 QDSL 的有序性，而对于大 QD，超晶格结构的有序性得到改善，点间距离低至 0.4nm，允许载流子通过 QDSL 快速传输。QDSL 的形成不会引起 QD 的吸收和光致发光光谱发生显著变化。然而，由于出现非辐射弛豫通道，发光衰减时间大大缩短。
