Light‐Driven Reversible Intermolecular Proton Transfer at Single‐Molecule Junctions

Abstract

Photoresponsive molecular systems are essential for molecular optoelectronic devices, but most molecular building blocks are non‐photoresponsive. Employed here is a photoinduced proton transfer (PIPT) strategy to control charge transport through single‐molecule azulene junctions with visible light under ambient conditions, which leads to a reversible and controllable photoresponsive molecular device based on non‐photoresponsive molecules and a photoacid. Also demonstrated is the application of PIPT in two single‐molecule AND gate and OR gate devices with electrical signal as outputs.

Chemically and Mechanically Controlled Single-Molecule Switches Using Spiropyrans

“…The goals of molecular electronics have progressed beyond the need for simple molecular conductors, and thus the need to develop switches, transistors, and diodes has become paramount. − Molecular junctions mimicking solid-state transistors and diodes have been addressed using light, pH, and electrochemical potential using a wide range of molecules. − To date, most of these molecular circuits respond to specific stimuli or have a limited change in their structure upon exposure to a stimulus, which limits their applications in nanocircuitry.…”

Quantum Interference Enhanced Chemical Responsivity in Single‐Molecule Dithienoborepin Junctions

“…The singlemolecule charget ransport investigations through azulene derivativesw ith different connectivities in the presence of protons show that ah igher conductance value of more than one order of magnitude fort he protonated state comparedw ith the neutral state. [14,15] Liu et al showedt hrough single-molecule conductance measurements an enhancement of conductance of up to 200 times when phenothiazine derivatives undergo reactionint he presence of acid oxidants. [16] To wards more selective sensing, Lewis acid-base interactions are introducedfor the sensingo ff luoridei ons through boronfluoride coordination, whereas the conductance difference is limitedt oa round 4t imes and is not sufficient for sensing applications.…”

Solvent-molecule interaction induced gating of charge transport through single-molecule junctions

“…1c and d). The dashed circles represent the overlapped area of the molecular plateaus [21]. Insets of Fig.…”

“…Various intrinsic molecular factors have been investigated to advance the understanding on their effect on singlemolecule junction conductance, such as conformation [7][8][9], anchor groups [10,11], electrodes [12], hybridization [13], and quantum interference [14][15][16]. By altering these parameters, molecular switching can be achieved due to changing redox states [17][18][19], protonation [20,21], and connectivity [3]; however, the molecular states have been restricted to be less than three. Electrochemical and electrostatic gating [22,23] are also promising approaches for tuning the energy level alignment, although the additional gate electrode has been found to bring technical challenges for the integration.…”