Copper Sulfide Nanocrystals with Tunable Composition by Reduction of Covellite Nanocrystals with Cu+ Ions

详细信息    查看全文

• 作者：Yi Xie ; Andreas Riedinger ; Mirko Prato ; Alberto Casu ; Alessandro Genovese ; Pablo Guardia ; Silvia Sottini ; Claudio Sangregorio ; Karol Miszta ; Sandeep Ghosh ; Teresa Pellegrino ; Liberato Manna
• 刊名：Journal of the American Chemical Society
• 出版年：2013
• 出版时间：November 20, 2013
• 年：2013
• 卷：135
• 期：46
• 页码：17630-17637
• 全文大小：425K
• 年卷期：v.135,no.46(November 20, 2013)
• ISSN：1520-5126

文摘

Platelet-shaped copper sulfide nanocrystals (NCs) with tunable Cu stoichiometry were prepared from Cu-rich covellite (Cu_1.1S) nanoplates through their reaction with a Cu(I) complex ([Cu(CH₃CN)₄]PF₆) at room temperature. Starting from a common sample, by this approach it is possible to access a range of compositions in these NCs, varying from Cu_1.1S up to Cu₂S, each characterized by a different optical response: from the metallic covellite, with a high density of free carriers and strong localized surface plasmon resonance (LSPR), up to Cu₂S NCs with no LSPR. In all these NCs the valency of Cu in the lattice stays always close to +1, while the average 鈭? valency of S in covellite gradually evolves to 鈭? with increasing Cu content; i.e., sulfur is progressively reduced. The addition of copper to the starting covellite NCs is similar to the intercalation of metal species in layered transition metal dichalcogenides (TMDCs); i.e., the chalcogen鈥揷halcogen bonds holding the layers are progressively broken to make room for the intercalated metals, while their overall anion sublattice does not change much. However, differently from the TMDCs, the intercalation in covellite NCs is sustained by a change in the redox state of the anion framework. Furthermore, the amount of Cu incorporated in the NCs upon reaction is associated with the formation of an equimolar amount of Cu(II) species in solution. Therefore, the reaction scheme can be written as: Cu_1.1S + 2纬Cu(I) 鈫?Cu_1.1+纬S + 纬Cu(II).