Influence of the substituents of the thiol ligand on the optical properties of AuCu 14 .

Detailed photophysical processes of two AuCu 14 clusters with different substituents (-F or -C(CH 3 ) 3 ) of the thiol ligand were studied in this work. The electronic effect of the substituents led to structural shrinkage, thus enhancing the luminous intensity. The internal conversion (IC) and intersystem crossing (ISC) rates in the AuCu14-C(CH3)3 crystal were slower compared with the AuCu14-F crystal, which was caused by the steric effect.