Mechanically inducible fluorescence colour switching in the formation of organic nanoparticles of an ESIPT molecule.

Electrostatic interactions between an ESIPT molecule 2-(5'-amino-2'-hydroxyphenyl)benzothiazole (AHBT) and a phenylborate derivative give blue-green emission in acetic acid solution, but interestingly, vigorous (or mechanical) shaking of the solution leads to the formation of organic AHBT nanoparticles, which results in fluorescence colour switching from blue-green to yellow-orange.