Enhanced coupling through π-stacking in imidazole-based molecular junctions. Issue 43 (23rd September 2019)

• Record Type: Journal Article
• Authors: Fu, Tianren; Smith, Shanelle; Camarasa-Gómez, María; Yu, Xiaofang; Xue, Jiayi; Nuckolls, Colin; Evers, Ferdinand; Venkataraman, Latha; Wei, Sujun
• Is Part Of: Chemical science. Volume 10:Issue 43(2019)
• Page Start: 9998
• Page End: 10002
• Publication Date: 2019-09-23
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c9sc03760h
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : We demonstrate that imidazole based π–π stacked dimers form strong and efficient conductance pathways in single-molecule junctions using the scanning-tunneling microscope-break junction (STM-BJ) technique and density functional theory-based calculations. Abstract : We demonstrate that imidazole based π–π stacked dimers form strong and efficient conductance pathways in single-molecule junctions using the scanning-tunneling microscope-break junction (STM-BJ) technique and density functional theory-based calculations. We first characterize an imidazole-gold contact by measuring the conductance of imidazolyl-terminated alkanes (im- N -im, N = 3–6). We show that the conductance of these alkanes decays exponentially with increasing length, indicating that the mechanism for electron transport is through tunneling or super-exchange. We also reveal that π–π stacked dimers can be formed between imidazoles and have better coupling than through-bond tunneling. These experimental results are rationalized by calculations of molecular junction transmission using non-equilibrium Green's function formalism. This study verifies the capability of imidazole as a Au-binding ligand to form stable single- and π-stacked molecule junctions at room temperature.