Crystalline nanoscale assembly of gold clusters for reversible storage and sensing of CO2 via modulation of photoluminescence intermittency

We report that zinc mediated crystalline nanoscale assemblies of atomic gold nanoclusters (NCs) were able to reversibly store gaseous carbon dioxide with adsorption capacity of 1.79 mM g(-1) at 20 degrees C and 20 bar. Importantly, carbon dioxide induced reversible change in photoluminescence intermittency of the assembled clusters indicated CO2 storage using confocal laser scanning microscopy. Au-14 NCs, having a single valued on time, exhibited a wide distribution of off time blinking profiles that could be fitted with truncated power law. However, blinking of ligand-stabilized Au-14 NCs was eliminated following the formation of zinc ion mediated three dimensional crystalline assemblies of Au-14 NCs. In the presence of carbon dioxide, single crystalline assembled nanoclusters showed intermittency behavior of the original clusters. However, upon desorption of carbon dioxide, the non-blinking nature of the crystalline assembly was restored.