Mechanical Tuning of Through‐Molecule Conductance in a Conjugated Calix[4]pyrrole

Abstract

A conformationally flexible calix [4]pyrrole possessing a conjugated electronic structure (an N-substituted oxoporphyrinogen (OxP) related to porphyrin) was used to investigate the influence of mechanical stretching on the single-molecule conductance of these molecules using the mechanicallycontrolled break junction (MCBJ) technique. The results show that the molecule can be immobilized in a single-molecule break junction configuration, giving rise to different behaviours.These include step-like features in the conductance vs. displacement traces as well as conductance traces that exhibit a slower decay ('downhill' traces) than measured for direct tunneling. The latter class of traces can be associated with the mechanical manipulation (i. e., stretching) of the molecule with inter-electrode distances as long as 2 nm. Density functional theory (DFT) calculations reveal that OxP molecules are stable under stretching in the length regime studied.

Self-assembly as a key player for materials nanoarchitectonics

“…Further to historical efforts in organic synthesis and materials' fabrication, functional optimization of materials involving structural regulation at the atomic/molecular scales and nanometre scales has been widely investigated and has been accompanied by the corresponding developments in observational techniques and instrumentation on those length scales [37][38][39]. While it is widely appreciated that nanotechnology plays a central role in materials developments involving nanoscale structures, nanotechnology also provides substantial benefits in the development of nanoscale observation and fabrication techniques including deepening our understanding of novel phenomena on the nanoscale and their guiding physical principles [40][41][42][43]. The construction of functional materials from nanoscale units requires essential contributions from non-nanotechnology fields such as supramolecular chemistry with self-assembly/selforganization [44][45][46][47], materials fabrications [48][49][50], and biotechnology [51][52][53][54][55].…”

Bottom-Up Self-Assembled Supramolecular Structures Built by STM at Solid/Liquid Interface

“…The breakthrough for the development of organic devices is to develop smart devices able to replace all silicon semiconductor components. The trend is to learn with biological systems [79][80][81][82][83][84][85].…”

“…However, most of the mechanisms of biological systems still remain unknown. The focus has been centered in studying individual biological molecules [83,84].…”

Mechanical Tuning of Giant Magnetoresistance and Spin Filtering in Manganese Diporphyrin‐Based Molecular Junction

“…In addition, metal‐porphyrin can be bridged by conjugative linkers and form conjugative metal‐porphyrin molecular dimer, but the corresponding spin transport properties have not been investigated. Moreover, in the process of mechanically controllable break junction (MCBJ) experiment, mechanical stretching and compressing can induce molecular dimer deformation ,. For example, Stefani et al .…”

“…For example, Stefani et al . demonstrated that the angle of conjugated calix[4]pyrrole molecule can be tuned by MCBJ technique, and the corresponding single molecule conductance exhibits a slower decay than measured for direct tunneling . So, in this paper, we have investigated the spin transport properties of a series of manganese diporphyrin (MnDP) by mechanical tuning of different dihedral angle by employing spin‐polarized density functional theory (DFT) combined with non‐equilibrium Green's function technique (NEGF).…”