Indirect ligand exchange methods have been demonstrated to replace the oleylamine capping with dodecanethiol for germanium nanocrystals (Ge NCs). In these methods, hydrazine is employed to effectively remove the oleylamine ligand before the NCs are passivated by microwave-assisted heating with dodecanethiol. In this work, octadecanethiol passivation is accomplished by the in situ reaction of dioctadecyl disulfide with diphenylphosphine. ¹H NMR and FTIR are used to characterize the surface ligand capping and the effectiveness of ligand exchange. Thiol passivation is achieved either by an exchange reaction at room temperature or by using microwave-assisted heating. Indirect and direct ligand exchange methods are demonstrated to be effective. The microwave-assisted reaction of GeI₂ with dioctadecyl disulfide also achieves thiol passivation without interfering in the formation of Ge NCs. Additional experiments study the effects of nanoparticle synthesis temperature, solvent, and ligand concentration on the exchange of oleylamine for octadecanethiol ligands.

中文翻译：

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二有机基二硫属元素化物作为锗纳米晶的表面封端配体

对于锗纳米晶体（Ge NCs），间接配体交换方法已被​​证明用十二烷硫醇取代油胺封端。在这些方法中，在用十二烷硫醇通过微波辅助加热将NC钝化之前，使用肼来有效去除油胺基配体。在这项工作中，十八烷硫醇钝化是通过二硫化二十八烷基与二苯基膦的原位反应完成的。¹ H NMR和FTIR用于表征表面配体封端和配体交换的有效性。硫醇钝化可通过在室温下进行交换反应或使用微波辅助加热来实现。间接和直接配体交换方法被证明是有效的。GeI的微波辅助反应具有二十八烷基二硫化物的₂也可实现硫醇钝化，而不会干扰Ge NCs的形成。其他实验研究了纳米颗粒合成温度，溶剂和配体浓度对油胺置换十八烷硫醇配体的影响。