A redox-active radical as an effective nanoelectronic component: stability and electrochemical tunnelling spectroscopy in ionic liquids

Abstract

A redox-active persistent perchlorotriphenylmethyl (PTM) radical chemically linked to gold exhibits stable electrochemical activity in ionic liquids. Electrochemical tunnelling spectroscopy in this medium demonstrates that the PTM radical shows a highly effective redox-mediated current enhancement, demonstrating its applicability as an active nanometer-scale electronic component.

Exploiting the versatile alkyne-based chemistry for expanding the applications of a stable triphenylmethyl organic radical on surfaces

“…Other parameters such as temperature and/or reaction time did not lead to a higher Fc surface coverage. The bulkiness of the PTM moieties, which can induce certain disorder of the layer, as was observed before by STM for a previously reported thiolated PTM SAM, 60 would be responsible for the yield decrease. Fig.…”

“…[80][81][82] The intensity at around 282.2 eV corresponds to transitions from the C 1s core levels to the singly unoccupied molecular orbital (SUMO). 60 The determination of the average molecular orientation of SAM-5-Rad is very challenging, the Cl-L edge signal shows a very weak dichroism (Fig. 7a), and the resonances in the C-K edge spectra due to transitions from aromatic carbon atoms are all very close in energy (Fig.…”

Perspectives for polychlorinated trityl radicals

“…The redox activity of the PTM SAMs have also been investigated at the nanoscale by electrochemical scanning tunnelling spectroscopy (EC-STS) in a ionic liquid medium. 30,31 Electrochemical STS measurements in the constant bias mode were performed. 32 In this mode, the potentials of the substrate E S and the tip E T were swept simultaneously while keeping the bias voltage E bias = E T -E S constant.…”

“…The STS results demonstrated a significant enhancement of the tunnelling current flowing between the substrate and the tip close to the equilibrium potential of the PTM radical/PTM anion redox pair, resembling a transistor like functionality (Figure 2b). 30 Such behaviour is typical of a redox mediated electron tunnelling (RMET) process, 33,34 which is rationalised by a two-step electron transfer. In the first one, the electron transfers from the electrode with a higher Fermi level to the single-unoccupied molecular orbital (SUMO).…”

A PROXYL‐Type Norbornene Polymer for High‐Voltage Cathodes in Lithium Batteries

“…Diaryl nitroxide radicals currently give the highest redox potentials of over 4 V versus Li/Li + , although the long-term stability is not ideal. [20,21] Nitronyl nitroxide (3.5 V), [15] verdazyl (around 2.9 V), [22] and triphenylmethyl radicals (around 2.9 V) [23] would offer improved stability, but lower voltages. On the other hand, a nitroxide radical with a five-membered ring, tetramethylpyrrolidine 1-oxyl (PROXYL), and their derivatives are reported as chemically robust and to give higher potentials than TEMPO (≈3.7 V).…”