A light-driven reversible conductance switch based on a few-walled carbon nanotube/azobenzene hybrid linked by a flexible spacer

An azobenzene molecule (AZO) with a flexible alkyl chain was attached to the sidewall of few-walled carbon nanotube (FWCNT) to form a FWCNT-chain-AZO hybrid by covalent bonding. Transmission electron microscopy image shows individually well-dispersed FWCNT packed underneath AZO molecules. The flexible spacer between the FWCNT and the AZO led to the efficient photoisomerization and thermal reversibility of the FWCNT-chain-AZO due to an increase of free volume. A light-driven electronic switch based on two FWCNT/AZO hybrids was fabricated. Current–voltage plots showed a marked continuous increase in conductance of the FWCNT-chain-AZO switch due to efficient trans-to-cis photoisomerization. Reversible conductance of the electronic switch during multiple cycles through on/off switching of the light was obtained due to reversible conformation changes.