Abstract: In OLEDs, improved efficiency is obtained by compounds which can form inter alia electron injection layers of the formula (I) wherein R1 is a 1-5 ring aryl (including polycyclic), aralkyl or heteroaryl group which is optionally substituted with one or more C1-C4 alkyl, alkoxy or cyano; R2 and R3 together form a 1-5 ring aryl (including polycyclic), aralkyl or heteroaryl group which is optionally substituted with C1-C4 alkyl, alkoxy or cyano; R4 is hydrogen, C1-C4 alkyl or aryl; and Ar is monocyclic, bicyclic or tricyclic aryl or heteroaryl which is optionally substituted with one or more C1-C4-alkyl or alkoxy groups, or an oligomer thereof.

Abstract: Electroluminescent devices are disclosed comprising a transparent anode; a layer of a hole transporting material; a layer of an electroluminescent material; a layer of an electron transporting material; a layer of a substituted lithium quinolate; and a metal cathode. The electroluminescent device may be an organic light-emitting diode having a cathode, an electron injection layer in contact with the cathode and an electron transport layer in contact with the electron injection layer and comprising aluminum, zirconium or hafnium quinolate or a mixture thereof or a mixture of any of them with a quinolate of a metal of group 1, 2, 3, 13 or 14 of the periodic table. Such devices may be made by the steps of forming a substituted lithium quinolate having one or more substituents and depositing the substituted lithium quinolate on a cathode of the device to provide an electron injection layer.

Abstract: The invention provides new compounds of the formula I, II or III. These compounds can be used as electron transport materials in optical light emitting diodes (OLEDs).

Abstract: In OLEDs, improved efficiency is obtained by compounds which can form inter alia electron injection layers of the formula (I) wherein R1 is a 1-5 ring aryl (including polycyclic), aralkyl or heteroaryl group which is optionally substituted with one or more C1-C4 alkyl, alkoxy or cyano; R2 and R3 together form a 1-5 ring aryl (including polycyclic), aralkyl or heteroaryl group which is optionally substituted with C1-C4 alkyl, alkoxy or cyano; R4 is hydrogen, C1-C4 alkyl or aryl; and Ar is monocyclic, bicyclic or tricyclic aryl or heteroaryl which is optionally substituted with one or more C1-C4-alkyl or alkoxy groups, or an oligomer thereof.

Abstract: In OLEDs, improved efficiency is obtained by compounds which can form inter alia electron injection layers of the formula (I) wherein R1 is a 1-5 ring aryl (including polycyclic), aralkyl or heteroaryl group which is optionally substituted with one or more C1-C4 alkyl, alkoxy or cyano; R2 and R3 together form a 1-5 ring aryl (including polycyclic), aralkyl or heteroaryl group which is optionally substituted with C1-C4 alkyl, alkoxy or cyano; R4 is hydrogen, C1-C4 alkyl or aryl; and Ar is monocyclic, bicyclic or tricyclic aryl or heteroaryl which is optionally substituted with one or more C1-C4-alkyl or alkoxy groups, or an oligomer thereof.

Abstract: In OLEDs, improved efficiency is obtained by compounds which can form inter alia electron injection layers of the formula (I) wherein R1 is a 1-5 ring aryl (including polycyclic), aralkyl or heteroaryl group which is optionally substituted with one or more C1-C4 alkyl, alkoxy or cyano; R2 and R3 together form a 1-5 ring aryl (including polycyclic), aralkyl or heteroaryl group which is optionally substituted with C1-C4 alkyl, alkoxy or cyano; R4 is hydrogen, C1-C4 alkyl or aryl; and Ar is monocyclic, bicyclic or tricyclic aryl or heteroaryl which is optionally substituted with one or more C1-C4-alkyl or alkoxy groups, or an oligomer thereof.

Abstract: The invention provides new compounds of the formula I, II or III. These compounds can be used as electron transport materials in optical light emitting diodes (OLEDs).

Abstract: In OLEDs, improved efficiency is obtained by novel compounds which can form inter alia electron injection layers of the formula (I) wherein R1 is a 1-5 ring aryl (including polycyclic), aralkyl or heteroaryl group which is optionally substituted with one or more C1-C4 alkyl, alkoxy or cyano; R2 and R3 together form a 1-5 ring aryl (including polycyclic), aralkyl or heteroaryl group which is optionally substituted with C1-C4 alkyl, alkoxy or cyano; R4 is hydrogen, C1-C4 alkyl or aryl; and Ar is monocyclic, bicyclic or tricyclic aryl or heteroaryl which is optionally substituted with one or more C1-C4-alkyl or alkoxy groups, or an oligomer thereof.

Abstract: Embodiments of electroluminescent devices of the invention are preferably formed of a transparent anode; a layer of a hole transporting material; a layer of an electroluminescent material; a layer of an electron transporting material; a layer of lithium quinolate or of a substituted lithium quinolate e.g. of thickness less than 7 nm; and a metal cathode. The layer of the metal quinolate is preferably about 0.3-0.5 nm in thickness.

Abstract: In an OLED there is a reflectivity influencing layer (27) which is preferably semi-absorbent and in embodiments is dark coloured or black which is formed of a sublimable organometallic compound. The reflectivity influencing layer is formed between an electrode (29 or 22) and a light-emitting layer (25).