Controlling Band Gap Energies in Cluster-Assembled Ionic Solids through Internal Electric Fields
Controlling Band Gap Energies in Cluster-Assembled Ionic Solids through Internal Electric Fields
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DOI：
10.1021/nn101640r
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发表时间：
2010-10-01
期刊：
影响因子：
17.1
通讯作者：
Sen, Ayusman
中科院分区：
文献类型：
--
作者：
Chaki, Nirmalya K.;Mandal, Sukhendu;Sen, Ayusman
组装团簇排列在不同结构中的离子固体是开发带隙工程纳米材料的一种很有前途的策略。我们合成了一系列由[As-7-Au-2-As-7](4-)组成的零维、一维和二维团簇组装离子固体。更高的连接性有望通过展宽带隙来降低带隙能量。然而，光学测量表明，当从零维组装到二维组装时，禁带能从1.69 eV增加到1.98 eV。这种增加是相邻反离子产生的局域电场的结果，它优先稳定占据的团簇电子态。
Assembling ionic solids where clusters are arranged in different architectures is a promising strategy for developing band gap-engineered nanomaterials. We synthesized a series of cluster-assembled ionic solids composed of [As-7-Au-2-As-7](4-) in zero-, one-, and two-dimensional architectures. Higher connectivity is expected to decrease the band gap energy through band broadening. However, optical measurements indicate that the band gap energy increases from 1.69 to 1.98 eV when moving from zero- to two-dimensional assemblies. This increase is a result of the local electric fields generated by the adjacent counterions, which preferentially stabilize the occupied cluster electronic states.