FUNCTIONAL MOLECULAR JUNCTIONS BASED ON IN SITU CHEMICAL REACTIONS

Abstract

This thesis mainly focuses on the study of functional molecular junctions based on in situ chemical reactions. First, we focus on the charge transport properties and functionalities of hexaazatrinaphthylene (HATNA) derivatives molecular junctions based on proton-coupled electron transfer (PCET). The junctions were dynamic and shown reconfigurable between a variable resistor, diode, 1D-1R memory, and hysteric NDR. By controlling the measurement atmosphere, the NDR effect was controlled and displayed a kinetic isotope effect. By introducing electron-donating or withdrawing groups to tune the frontier orbitals of the HATNA molecules, the NDR peaks were shifted or disappeared. By designing different numbers of quinoxaline units of HATNA derivatives, the peak-to-valley ratio and the peak shape of NDR were changed according to the different amounts of PCET steps. At the last, we study the molecular diode function in porphyrin molecular junctions by changing the central metal ions to tune the energy levels of porphyrin molecules.