Intercluster aurophilicity-driven aggregation lighting circularly polarized luminescence of chiral gold clusters

Herein, we prepared two novel pairs of enantiomeric gold cluster complexes, AU 4 PL 4 /Au 4 PD 4 and ( Au 4 L 4 ) n /( Au 4 D 4 ) n with atomic precision. In Au 4 PL 4 /Au 4 PD 4 , the discrete chiral Au 4 -based aggregation-induced emission (AIE) luminogens are separated by bulky substitutes. The corresponding aggregates are cyan-emitting with a photoluminescence quantum yield (PLQY) of 14.4%. Upon decreasing the size of the substituents, these chiral Au 4 clusters are strung together by inter-cluster Au-Au interactions, which cause a low-energy green emission from the aggregated ( Au 4 L 4 ) n /(Au 4 D 4 ) n with a much higher PLQY of 41.4% and more intense circularly polarised photoluminescence (CPL) with a dissymmetry factor | g PL | of 7.0 × 10 − 3 . Using ( Au 4 L 4 ) n / (Au 4 D 4 ) n , circularly polarised organic light-emitting diodes (CP-OLEDs) were for the first time fabricated with | g EL | = | g PL |. These findings signify that inter-cluster metallophilic interactions are a new and important type of driving force for AIE and crystallization-induced emission (CIE), suggesting great potential of CPL-active metal clusters in CP-OLEDs.