Scanning tunneling microscopy and transmission electron microscopy of Langmuir-blodgett films of three donor-sigma-acceptor molecules: BDDAP-C-HETCNQ, BDDAP-C-HPTCNQ and BDDAP-C-HBTCNQ

Abstract Langmuir-Blodgett films of three very similar molecules, BBDAP-C-HETCNQ ( 1 ), BDDAP-C-HPTCNQ ( 2 ), and BDDAP-C-HBTCNQ ( 3 ) were studied by STM and TEM. The areas per molecule and the STM resolution decrease in the order 1 to 2 to 3 : it seems that disorder increases, and that a trivial change in the σ bridge linking the medium electron donor BDDAP to the strong electron acceptor TCNQ in these three molecules causes major changes in the films.