Helical Ribbons for Molecular Electronics

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• 作者：Yu Zhong ; Bharat Kumar ; Seokjoon Oh ; M. Tuan Trinh ; Ying Wu ; Katherine Elbert ; Panpan Li ; Xiaoyang Zhu ; Shengxiong Xiao ; Fay Ng ; Michael L. Steigerwald ; Colin Nuckolls
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：June 4, 2014
• 年：2014
• 卷：136
• 期：22
• 页码：8122-8130
• 全文大小：697K
• 年卷期：v.136,no.22(June 4, 2014)
• ISSN：1520-5126

文摘

We describe the design and synthesis of a new graphene ribbon architecture that consists of perylenediimide (PDI) subunits fused together by ethylene bridges. We created a prototype series of oligomers consisting of the dimer, trimer, and tetramer. The steric congestion at the fusion point between the PDI units creates helical junctions, and longer oligomers form helical ribbons. Thin films of these oligomers form the active layer in n-type field effect transistors. UV鈥搗is spectroscopy reveals the emergence of an intense long-wavelength transition in the tetramer. From DFT calculations, we find that the HOMO鈥? to LUMO transition is isoenergetic with the HOMO to LUMO transition in the tetramer. We probe these transitions directly using femtosecond transient absorption spectroscopy. The HOMO鈥? to LUMO transition electronically connects the PDI subunits with the ethylene bridges, and its energy depends on the length of the oligomer.