Geisenhoff Jessica Q, Pan Yuanhui, Yin Hang, Paesani Francesco, Schimpf Alina M
Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States.
Program in Materials Science and Engineering, University of California, San Diego, La Jolla, California 92093, United States.
Chem Mater. 2024 Sep 9;36(18):8834-8845. doi: 10.1021/acs.chemmater.4c01602. eCollection 2024 Sep 24.
We report a synthesis of WSe nanocrystals in which the number of layers is controlled by varying the precursor concentration. By altering the ratios and concentrations of W(CO) and PhSe in trioctylphosphine oxide, we show that high [Se] and large Se/W ratios lead to an increased number of layers per nanocrystal. As the number of layers per nanocrystal is increased, the nanocrystal ensembles show less phase-conversion from the metastable 2M phase to the thermodynamically favored 2H phase. Density functional theory calculations indicate that the interlayer binding energy increases with the number of layers, indicating that the stronger interlayer interactions in multilayered nanocrystals may increase the energy barrier to phase-conversion. The results presented herein provide insights for directing phase-conversion in solution-phase syntheses of transition metal dichalcogenides.
我们报道了一种WSe纳米晶体的合成方法，其中层数通过改变前驱体浓度来控制。通过改变三辛基氧化膦中W(CO)和PhSe的比例和浓度，我们发现高[Se]和大的Se/W比会导致每个纳米晶体的层数增加。随着每个纳米晶体层数的增加，纳米晶体集合体从亚稳的2M相到热力学上更有利的2H相的相转变减少。密度泛函理论计算表明，层间结合能随着层数的增加而增加，这表明多层纳米晶体中更强的层间相互作用可能会增加相转变的能垒。本文给出的结果为指导过渡金属二硫属化物溶液相合成中的相转变提供了见解。
