Aggregation induced delayed green fluorescence from assembly of gold nanoclusters: an advanced probe for “background free” pyrophosphate recognition

Abstract

Aggregation induced emission (AIE), ever since its inception, has received remarkable attention from scientists pursuing research towards the development of advanced optical materials. Thus, a plethora of light emitting materials have been reported, based on the principle of AIE, as functional components in light emitting diodes and cell imaging probes. On the other hand, recent advancement in the field of organic electronics has been witnessed through rational implementation of the concept of delayed fluorescence (DF). Due to their long luminescence lifetime, DF materials also portend to be ideal candidates for elimination of the interference of auto fluorescence and thereby allow accurate sensing of chemical species. Thus, development of AIE-based DF materials may be a way forward in the field of molecular and ion recognition. Herein, we report that non-luminescent gold nanoclusters, upon complexation reaction with zinc ions, exhibit delayed fluorescence with a quantum yield as high as 6% and an average lifetime of 17.67 μs. The delayed green fluorescence of the aggregates of gold clusters was further used for “background free” probing of pyrophosphate ions.