SYNTHESIS OF PRECURSORS FOR MOLECULAR ELECTRONICS

Abstract

The design of molecular rectifiers is one of the major topics of research in molecular electronics, however the relationship between the molecular structure and the electrical characteristics of molecular rectifiers is not fully understood. To elucidate this relationship, we synthesized and examined the electrical properties of fluorinated benzalkylsilane self-assembled monolayers (SAMs) of varying lengths and terminal groups. The rectification ratios were determined to be as high as ~200 and we also found that the rectification ratio correlates positively with the strength of the molecular dipole moment particularly for shorter chain molecules. Based on this data, we sought to design short chain benzalkylsilane SAMs with strong electron withdrawing and strong electron donating terminal groups. We hypothesized that terminations with these groups would give us enhanced rectification ratios based on their large dipole moments. Rectification ratios were found to be as high as 2635. These values to our knowledge are the highest reported for small molecule rectifiers assembled on silicon substrates.