Abstract
To design innovative and novel optical materials with high mobility, two kinds of disubstituted derivatives for meridianal isomer of tris(8-hydroxyquinolinato)aluminum (
mer-Alq3) with push–pull (X–Y) substituents have been designed. The structures of tris(4-X-6-Y-8-hydroxyquinolinato)aluminum (type 1) and tris(4-Y-6-X-8-hydroxyquinolinato)aluminum (type 2) (where X
=
–CH
3/–NH
2 and Y
=
–CN/–Cl) in the ground (S
0) and first excited (S
1) states have been optimized at the B3LYP/6-31G
∗ and CIS/6-31G
∗ level of theory, respectively. All the designed derivatives of type 1 show blue shift while most of the type 2 derivatives show red shift as compared to the
mer-Alq3. The emitting color could be tuned from blue to red. We have explained the distribution of HOMOs and LUMOs on different individual ligands. The reorganization energies of tris(4-methyl-6-chloro-8-hydroxyquinolinato)aluminum (
1), tris(4-methyl-6-cyano-8-hydroxyquinolinato) aluminum (
2), tris(4-chloro-6-methyl-8-hydroxyquinolinato)aluminum (
5) and tris(4-cyano-6-methyl-8-hydroxyquinolinato)aluminum (
6) are comparable with
mer-Alq3. Thus these derivatives might be good candidates for emitting materials possessing comparable charge carrier mobility as
mer-Alq3.