Kim Taewan, Park Seongmin, Jeong Sohee
Department of Energy Science (DOES) and Center for Artificial Atoms, Sungkyunkwan University (SKKU), Suwon, Gyeonggi-do, South Korea.
Nat Commun. 2021 May 21;12(1):3013. doi: 10.1038/s41467-021-23259-w.
Highly monodisperse colloidal InAs quantum dots (QDs) with superior optoelectronic properties are promising candidates for various applications, including infrared photodetectors and photovoltaics. Recently, a synthetic process involving continuous injection has been introduced to synthesize uniformly sized InAs QDs. Still, synthetic efforts to increase the particle size of over 5 nm often suffer from growth suppression. Secondary nucleation or interparticle ripening during the growth accompanies the inhomogeneity in size as well. In this study, we propose a growth model for the continuous synthetic processing of colloidal InAs QDs based on molecular diffusion. The experimentally validated model demonstrates how precursor solution injection reduces monomer flux, limiting particle growth during synthesis. As predicted by our model, we control the diffusion dynamics by tuning reaction volume, precursor concentration, and injection rate of precursor. Through diffusion-dynamics-control in the continuous process, we synthesize the InAs QDs with a size over 9.0-nm (1S of 1600 nm) with a narrow size distribution (12.2%). Diffusion-dynamics-controlled synthesis presented in this study effectively manages the monomer flux and thus overcome monomer-reactivity-originating size limit of nanocrystal growth in solution.
具有优异光电特性的高度单分散胶体铟砷量子点（QDs）是包括红外光电探测器和光伏在内的各种应用的有前途的候选材料。最近，一种涉及连续注入的合成工艺被引入来合成尺寸均匀的铟砷量子点。然而，增加粒径超过5nm的合成努力往往受到生长抑制。生长过程中的二次成核或颗粒间熟化也伴随着尺寸的不均匀性。在本研究中，我们基于分子扩散提出了一种用于胶体铟砷量子点连续合成过程的生长模型。经过实验验证的模型展示了前驱体溶液注入如何降低单体通量，从而在合成过程中限制颗粒生长。正如我们的模型所预测的，我们通过调整反应体积、前驱体浓度和前驱体注入速率来控制扩散动力学。通过在连续过程中控制扩散动力学，我们合成了尺寸超过9.0nm（1S为1600nm）且尺寸分布狭窄（12.2%）的铟砷量子点。本研究中提出的扩散动力学控制合成有效地管理了单体通量，从而克服了溶液中纳米晶体生长中源于单体反应性的尺寸限制。
