Department of Chemistry and Institute of Materials Science and Engineering, Washington University , St. Louis, Missouri 63130-4899, United States.
ACS Nano. 2017 Dec 26;11(12):12526-12535. doi: 10.1021/acsnano.7b06639. Epub 2017 Nov 30.
Crystal-phase control is one of the most challenging problems in nanowire growth. We demonstrate that, in the solution-phase catalyzed growth of colloidal cadmium telluride (CdTe) quantum wires (QWs), the crystal phase can be controlled by manipulating the reaction chemistry of the Cd precursors and tri-n-octylphosphine telluride (TOPTe) to favor the production of either a CdTe solute or Te, which consequently determines the composition and (liquid or solid) state of the BiCdTe catalyst nanoparticles. Growth of single-phase (e.g., wurtzite) QWs is achieved only from solid catalysts (y ≪ z) that enable the solution-solid-solid growth of the QWs, whereas the liquid catalysts (y ≈ z) fulfill the solution-liquid-solid growth of the polytypic QWs. Factors that affect the precursor-conversion chemistry are systematically accounted for, which are correlated with a kinetic study of the composition and state of the catalyst nanoparticles to understand the mechanism. This work reveals the role of the precursor-reaction chemistry in the crystal-phase control of catalytically grown colloidal QWs, opening the possibility of growing phase-pure QWs of other compositions.
晶相控制是纳米线生长中最具挑战性的问题之一。我们证明，在胶体碲化镉 (CdTe) 量子线 (QW) 的溶液相催化生长中，可以通过操纵 Cd 前体和三辛基膦碲 (TOPTe) 的反应化学来控制晶相，从而有利于生成 CdTe 溶质或碲，这反过来又决定了 BiCdTe 催化剂纳米颗粒的组成和（液体或固体）状态。单相（例如，纤锌矿）QW 只能从固体催化剂（y << z）生长，这使得 QW 的固-固-固生长成为可能，而液体催化剂（y ≈ z）则满足多型 QW 的液-液-固生长。系统地考虑了影响前体转化化学的因素，并与催化剂纳米颗粒的组成和状态的动力学研究相关联，以理解其机制。这项工作揭示了前驱体反应化学在催化生长胶体 QW 中的晶相控制中的作用，为生长其他组成的相纯 QW 开辟了可能性。
