Patent ID: 8748012

Claim:
A compound of Formula I comprising: wherein Ar and Ar′ are independently selected from the group consisting of phenyl, biphenyl, napthyl, dibenzothiolyl, and dibenzofuranyl, which are optionally further substituted; wherein Z is selected from Si and Ge; wherein L 1 comprises aryl or heteroaryl groups, wherein any heteroatoms in the heteroaryl groups are nitrogen; wherein L 2 comprises aryl or heteroaryl groups, wherein any heteroatoms in the heteroaryl groups are nitrogen; wherein L 1 and L 2 are optionally further substituted; wherein A contains a group selected from the group consisting of dibenzofuran, dibenzothiophene, azadibenzofuran, azadibenzothiophene, dibenzoselenophene and azadibenzoselenophene, which are optionally further substituted, and wherein the substitution is optionally fused to at least one benzo ring; and wherein B contains a group selected from the group consisting of carbazole and azacarbazole, which are optionally further substituted, and wherein the substitution is optionally fused to the carbazole or azacarbazole group.