Controlling the crystal structure and shape and/or faceting of colloidal nanocrystals during growth through easily variable reaction parameters is highly desirable. The choice of precursors is one such parameter that can significantly impact achievable shapes and phases. Here, we examine how different Cu precursors in the synthesis of colloidal copper sulfide nanocrystals affect the resulting shape and crystal phase. An observed decreasing aspect ratio in one-dimensional nanorods (eventually transitioning to two-dimensional nanodisks) is consistent with the expected effects of decreasing Cu precursor reactivity. Nanorods are predominantly chalcocite at the early stages of growth, but a phase transition to djurleite occurs and is accompanied by a change in tip faceting upon further growth. In contrast, nanodisks appear in the djurleite phase early on and remain so upon continued growth. Localized surface plasmon resonance in various shapes of nanocrystals achieved is enhanced with chemical oxidation, and the near-field enhancement is also simulated.

中文翻译：

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铜前体反应性对硫化铜纳米晶体形状和相的影响

非常需要通过容易改变的反应参数来控制生长期间的胶体纳米晶体的晶体结构和形状和/或刻面。前体的选择就是这样一种参数，它会显着影响可实现的形状和相位。在这里，我们研究了胶体硫化铜纳米晶体合成中不同的铜前体如何影响最终的形状和晶相。一维纳米棒中观察到的纵横比降低（最终过渡到二维纳米盘）与降低Cu前驱体反应性的预期效果一致。纳米棒在生长的早期主要是辉绿岩，但会发生向金闪石的相变，并伴随着进一步生长时的尖端刻面变化。相比之下，纳米盘在早期出现在钙铝榴石相中，并在持续增长时保持不变。通过化学氧化增强了在各种形状的纳米晶体中实现的局部表面等离子体共振，并且还模拟了近场增强。