Anchor Groups for Graphene‐Porphyrin Single‐Molecule Transistors

Abstract

The effectiveness of five different anchor groups for non-covalent interfacing to graphene electrodes are compared. A family of six molecules is tested in single-molecule junctions: five consist of the same porphyrin core with different anchor groups, and the sixth is a reference molecule without anchor groups. The junction formation probability (JFP) has a strong dependence on the anchor group. Larger anchors give higher binding energies to the graphene surface, correlating with higher JFPs. The best anchor groups tested are 1,3,8-tridodecyloxypyrene and 2,5,8,11,14-pentadodecylhexa-peri-hexabenzocoronene, with JFPs of 36% and 38%, respectively. Many junctions are tested at 77 K for each molecule by measuring source-drain current as a function of bias and gate voltage. For each compound, there is wide variation in the strength of the electronic coupling to the electrodes and in the location of Coulomb peaks. In most cases, this device-to-device variability makes it impossible to observe trends between the anchor and the charge-transport characteristics. Tetrabenzofluorene anchors, which are not π-conjugated with the

Electronic Communication across Porphyrin Hexabenzocoronene Isomers

“…Aside from difficulties in the selective preparation of suitable compounds,another obstacle preventing SMECs from commercial application is based on the poor control over the connection of the molecules to the electrodes. [9] Break junction experiments,which rely on, for example, strong interactions between gold electrodes and sulfurcontaining anchor groups,p rove to be quite efficient in binding the molecules.However,they often fail in controlling the specific coordination site at the electrodes,which leads to fluctuations in each device performance. [2] Recently,avariety of molecules,i ncluding porphyrins, [9,10] oligothiophenes, [11] and hydrocarbons, [12] were investigated in single-molecule conductance studies in correlation to their length and conformational state.…”

Order from Chaos: Self‐Assembly of Nanoprism from a Mixture of Tetratopic Terpyridine‐Porphyrin Conformers

“…Free base porphyrins have been extensively studied in the biomedical fields, e.g ., clinical phototherapy and cancer imaging . Metallo‐porphyrins have been applied in sensors, molecular electronics, photovoltaic devices, ionophores and catalysts …”

Elektronische Kommunikation von Porphyrin‐Hexabenzocoronen‐Isomeren

“…B. in molekularen elektronischen Bauteilen verwendet. [8] Hierbei stellten sowohl die selektive Synthese der gewünschten Verbindungen als auch ein geringes Maß an Kontrolle über die Verknüpfung zwischen Molekülu nd Elektrode [9] eine Herausforderung dar.D iese Schwierigkeiten standen bis jetzt dem Durchbruch von elektronischen Bauteilen, die auf einzelnen Molekülen basieren, im Wege. Mechanisch kontrollierte Bruchkontakte,d ie z.…”

“…[2] Vor kurzem wurde eine Reihe an Molekülen wie z. B. Porphyrine, [9,10] Oligothiophene [11] und Kohlenwasserstoffe [12] in molekularen Leitfähigkeitsstudien verwendet, um den Zusammenhang zwischen der Länge und Konformation der Moleküle auf die elektronischen Eigenschaften zu untersuchen.…”