In OLEDs, improved efficiency is obtained by compounds which can form inter alia electron injection layers of the formula (I)
wherein
R
1
is a 1-5 ring aryl (including polycyclic), aralkyl or heteroaryl group which is optionally substituted with one or more C
1
-C
4
alkyl, alkoxy or cyano;
R
2
and R
3
together form a 1-5 ring aryl (including polycyclic), aralkyl or heteroaryl group which is optionally substituted with C
1
-C
4
alkyl, alkoxy or cyano;
R
4
is hydrogen, C
1
-C
4
alkyl or aryl; and
Ar is monocyclic, bicyclic or tricyclic aryl or heteroaryl which is optionally substituted with one or more C
1
-C
4
-alkyl or alkoxy groups, or an oligomer thereof.
在OLED中,可以通过化合物(I)形成包括电子注入层在内的改进效率,其中:
R1是1-5环芳基(包括多环)、芳基烷基或杂环芳基基团,可选地取代一个或多个C1-C4烷基、烷氧或
氰基;
R2和R3共同形成1-5环芳基(包括多环)、芳基烷基或杂环芳基基团,可选地取代C1-C4烷基、烷氧或
氰基;
R4是氢、C1-C4烷基或芳基;
Ar是单环、双环或
三环芳基或杂环芳基,可选地取代一个或多个C1-C4烷基或烷氧基团,或其寡聚物。