Tuning the work function of gold with self-assembled monolayers derived from X-[C6H4-CC-]nC6H4-SH (n = 0, 1, 2; X = H, F, CH3, CF3, and OCH3)

Changes in the work function of gold, Delta Phi(Au), induced by the formation of chemisorbed self-assembled monolayers derived from the series of titled arenethiol adsorbates X - (C6H4 - C equivalent to C-)(n)C6H4-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 fora 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.