Aggregation‐Induced Emission Properties of Copper Iodide Clusters

Abstract

The aggregation‐induced emission (AIE) properties of two different copper iodide clusters have been studied. These two [Cu4I4L4] clusters differ by their coordinated phosphine ligand and the luminescent mechanochromic properties are only displayed by one of them. The two clusters are AIE‐active luminophors that exhibit an intense emission in the visible region upon aggregation. The formed particles present luminescent thermochromism comparable to that of the bulk compounds. The observed AIE properties can be attributed to suppression of nonradiative relaxation of the excited states in a more rigid state, in relation to the large structural relaxation of the excited triplet state. The differences observed in the AIE properties of the two clusters can be related to the different ligands. A correlation between the luminescence mechanochromic properties and the AIE effect is not straightforward, but the formation of “soft” molecular solids is a common characteristic that can explain the photoactive properties of these compounds.

Combining Theory and Experiment to Get Insight into the Amorphous Phase of Luminescent Mechanochromic Copper Iodide Clusters

“…The AIE (Aggregation Induced Emission) properties of this solvate were previously studied and its mechanochromic luminescence properties were shown but not analyzed. 42 The structure of the two polymorphs were determined by single-crystal X-Ray diffraction analysis at 150 K, that of 1•CH3CN was already reported 41 but is anew described here for comparison with 1•THF.…”

The Multifarious Applications of Copper Nanoclusters in Biosensing and Bioimaging and Their Translational Role in Early Disease Detection

“…Although metal NCs require further studies on their AIE properties in order to ground a complete understanding of their exact mechanism of action, this mechanism has been generally associated with the limitations of the intramolecular motion of capping ligands in the aggregation states, blocking the non-radiative pathways, and subsequently activating the radiative decay, resulting in the PL enhancement of metal NCs [ 40 ]. As in Figure 2 , the emission of isolated metal NCs exhibits fluorescence (transition from S 1 to S 0 ), while aggregated NCs emit phosphorescence (transition from T 1 to S 0 ).…”

Molecular copper iodide clusters: a distinguishing family of mechanochromic luminescent compounds

“…We have thus studied the AIE properties of two different [Cu 4 I 4 L 4 ] copper iodide clusters and the correlation with their luminescence mechanochromism properties. 161 Characterizations of the suspensions show the formation of relatively stable particles of 250 nm mean diameter with a main amorphous character (Figure 8). These particles exhibit the luminescence thermochromism of the corresponding clusters.…”