Photo-induced interfacial electron transfer of ZnO nanocrystals to control supramolecular assembly in waterElectronic supplementary information (ESI) available: Materials and methods, detailed synthetic and experimental procedures and characterization. See DOI: 10.1039/c7nr03095a

Herein, we show how the inherent light-induced redox properties of semiconducting nanocrystals (NCs) can be utilized for the photo-driven reversible modulation of dynamic supramolecular systems formed at their interfaces that, on their own, do not respond to light. This was achieved by the unprecedented combination of photoactive zinc oxide NCs (ZnO NCs) with a host-guest chemistry of cucurbit[8]uril (CB[8]) providing a route to the semiconductor-assisted light modulation of supramolecular assemblies (SALSA), here mediated by the photo-generation of viologen radical cations (MV&z.rad; + ) at the NC corona and their further dimerization enhanced by CB[8] macrocycles. The reported SALSA strategy was successfully applied for light-controlled reversible assembly processes at NC interfaces enabling light-triggered release of guest molecules from surface confined discrete CB[8] host-guest complexes. The light-induced redox properties of semiconducting nanocrystals can be utilized for reversible modulation of non-photoresponsive interfacial supramolecular systems.