Tuning the Work Function of Gold with Self-Assembled Monolayers Derived from X−[C₆H₄−C⋮C−]<i>_n</i>C₆H₄−SH (<i>n</i> = 0, 1, 2; X = H, F, CH₃, CF₃, and OCH₃)

Abstract

Changes in the work function of gold, ΔΦ Au, induced by the formation of chemisorbed self-assembled monolayers derived from the series of titled arenethiol adsorbates X − (C 6 H 4 − C⋮C−) n C 6 H 4 −SH ( 1, n = 0; 2, n = 1; 3, n = 2) have been measured by the Kelvin probe method. An analysis of these data indicates that variation in work function for a given chain length can be effectively modeled with two dipole sheets, as has been shown for other classes of self-assembled monolayers. Importantly, it is shown that monolayers of class 1 produce larger relative changes in work function for a given substituent X than those of either 2 or 3, presumably as a result of the larger polarizability of the longer chains present in the latter. Accordingly, these commercially available adsorbates are attractive for use in device applications requiring work function modification.