Engineering Au Nanoclusters for Relay Luminescence Enhancement with Aggregation-Induced Emission

Abstract

The research of aggregation-induced emission (AIE) has been growing rapidly for the design of highly luminescent materials, as exemplified by the library of AIE-active materials (or AIEgens) fabricated and explored for diverse applications in different fields. Herein, we reported a relay luminescence enhancement of luminescent Au nanoclusters (Au NCs) through AIE. In addition, we demonstrated the emergence of reduced aggregation-caused luminescence by adjusting the temperature of the Au NC solution. The key to induce this effect is to attach a thermosensitive polymer poly(N-isopropylacrylamide) (PNIPAAm) on the surface of Au NCs, which will shrink at high temperature. More interestingly, the as-synthesized Au NCs-PNIPAAm can self-assemble into vesicles, resulting in an obvious decrease in the luminescence intensity in aqueous solution. The combination of relay luminescence enhancement (by AIE) and luminescence decrease (induced by thermosensitive polymers) will be beneficial to the understanding and manipulation of the optical properties of Au NCs, paving the way for their practical applications.

Luminescent Gold Nanoclusters for Bioimaging: Increasing the Ligand Complexity

“…In reality, several cappings were reported as efficient agents for the promotion of NPs’ aggregation or NPs’ disaggregation. Recently, AIE and AEE were reported as one of the most explored strategies to activate or increase the emission of AuNCs for a variety of applications, such as sensoring and imaging [ 41 , 42 ]. It was hypothesized that AIE and AEE were promoted by the blocking of intramolecular vibrational and rotational relaxation pathways, promoting radiative emission mechanisms [ 116 , 117 , 118 ].…”

“…Moreover, supra-particle systems can be formed upon AuNCs aggregation, leading to controllable and reversible changes in the PL. Recently, aggregation-induced emission (AIE) and aggregation-enhanced emission (AEE) were reported as one of the most explored strategies to activate or increase the emission of AuNCs tested for a variety of applications, such as sensoring and imaging [ 41 , 42 ].…”