McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas, 78712 (USA).
Department of Materials Science and Engineering, University of California Berkeley, Berkeley, California 94720 (USA).
Angew Chem Int Ed Engl. 2015 Dec 1;54(49):14840-4. doi: 10.1002/anie.201508641. Epub 2015 Oct 16.
For colloidal semiconductor nanocrystals (NCs), replacement of insulating organic capping ligands with chemically diverse inorganic clusters enables the development of functional solids in which adjacent NCs are strongly coupled. Yet controlled assembly methods are lacking to direct the arrangement of charged, inorganic cluster-capped NCs into open networks. Herein, we introduce coordination bonds between the clusters capping the NCs thus linking the NCs into highly open gel networks. As linking cations (Pt(2+)) are added to dilute (under 1 vol %) chalcogenidometallate-capped CdSe NC dispersions, the NCs first form clusters, then gels with viscoelastic properties. The phase behavior of the gels for variable [Pt(2+)] suggests they may represent nanoscale analogues of bridged particle gels, which have been observed to form in certain polymer colloidal suspensions.
对于胶体半导体纳米晶体（NCs），用化学性质不同的无机簇取代绝缘的有机封端配体，可开发出功能固体，其中相邻的 NCs 强耦合。然而，缺乏控制组装方法来指导带电荷的、无机簇封端的 NCs 排列成开放网络。在本文中，我们在 NC 表面的封端簇之间引入配位键，从而将 NC 连接成高度开放的凝胶网络。当向稀（低于 1%体积）的硒化/硫化物金属盐封端的 CdSe NC 分散体中加入连接阳离子（Pt(2+)）时，NC 首先形成簇，然后形成具有粘弹性的凝胶。凝胶的相行为随[Pt(2+)]的变化而变化，这表明它们可能代表桥联粒子凝胶的纳米级类似物，在某些聚合物胶体悬浮液中已经观察到它们的形成。
