Study On The Conductive Properties Of Curved Conjugated Monomolecule

The field of single molecule electronics uses engineering,physics,and chemistry expertise to achieve the miniaturization of circuit components.It is a branch of nanoelectronics,where electronic components are individual molecules.It is important to realize the characterization of single molecule charge transport and the regulation of molecular electronic structure in the field of single molecule electronics.In the past century,scientists have developed powerful methods to characterize and manipulate the electronic conductivity of single molecules,which promoted the development of functional single molecule devices.In the design and research of many organic single molecules,curved conjugated single molecules have a unique radialπconjugated structure and interesting electronic properties,and are extremely promising electronic materials for single molecule devices.With different curved conjugated single molecules,we characterized their electrical properties based on scanning tunneling microscope-break junction（STM-BJ）.We further invested the charge transport properties and potential functions at the sub-nanometer scale.The main research results are divided into the following two aspects:1.Based on the scanning tunneling microscope–break junction（STM-BJ）technique,we examine charge transport characteristics of a series of[n]CPPs at the single molecule level.We found that the[n]CPPs have a significantly higher conductance than their linear oligoparaphenylene counterparts at small ring size and at the same time show a large tunneling attenuation coefficient comparable to saturated alkane series.DFT calculation shows that the experimental results are consistent with the theoretical results.These results show that the radiallyπ-conjugated molecular systems can offer much larger conductance modulation range than standard linear molecules and can be a new platform for building molecular devices with highly tunable transport behaviors.2.Based on the scanning tunneling microscope–break junction（STM-BJ）technique,we examine charge transport characteristics of C₆₀ at the single molecule level.The experimental results show that C₆₀ molecules can form three different single molecule junctions.Theoretical calculation shows that three different junctions are caused by theπ-πstacking between C₆₀ molecules.And it is of great significance to the development of multifunctional single molecular electronic devices.