OLED electron-injecting layer

1. An organic light-emitting device (OLED) comprising in the following order:

a) an anode;

b) a light-emitting layer disposed over the anode;

c) a first electron-injecting layer disposed over the light-emitting layer, wherein the first electron-injecting layer includes at least one organic host material having a reduction potential less than −1.0 V vs. a Saturated Calomel Electrode selected from metal chelated oxinoid compounds and at least one dopant material capable of reducing the organic host material which is lithium;

d) a second electron-injecting layer disposed in direct contact with the first electron-injecting layer, wherein the second electron-injecting layer includes at least one organic material having a reduction potential greater than −1.0 V vs. a Saturated Calomel Electrode and is selected from the chemical compounds having the structure of

wherein R 1 -R 6 represent hydrogen or a substituent independently selected from the group consisting of halo, nitrile (—CN), nitro (—NO 2 ), sulfonyl (—SO 2 R), sulfoxide (—SOR), trifluoromethyl (—CF 3 ), ester (—CO—OR), amide (—CO—NHR or —CO— NRR′), substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, and substituted or unsubstituted alkyl, where R and R′ are substituted or unsubstituted alkyl or aryl; or wherein R 1 and R 2 , R 3 and R 4 , or R 5 and R 6 , combine to form a ring structure including an aromatic ring, a heteroaromatic ring, or a nonaromatic ring, and each ring is substituted or unsubstituted; and

e) a cathode disposed in direct contact with the second electron-injecting layer.

2. The OLED of claim 1 wherein the at least one organic material in the second electron-injecting layer has a reduction potential greater than −0.5 V vs. a Saturated Calomel Electrode and has an optical band gap greater than 1.6 eV.

3. The OLED of claim 1 wherein the first electron-injecting layer has a thickness in a range of from 2 to 150 nm.

4. The OLED of claim 1 wherein the second electron-injecting layer has a thickness in a range of from 1 to 150 nm.

5. The OLED of claim 1 wherein the at least one organic host material in the first electron-injecting layer is tris(8-hydroxyquinoline)-aluminum (Alq).

6. The OLED of claim 1 wherein the at least one organic material in the second electron-injecting layer includes a chemical compound having the structure

7. The OLED of claim 1 wherein the second electron-injecting layer includes at least one organic material having a reduction potential greater than −1.0 V vs. SCE and at least one dopant material having a work function less than 4.0 eV.

8. The OLED of claim 7 wherein the at least one dopant material in the second electron-injecting layer includes an alkali metal, alkali metal compound, alkaline earth metal, or alkaline earth metal compound.

9. The OLED of claim 7 wherein the at least one dopant material in the second electron-injecting layer is Li.

10. The OLED of claim 7 wherein the concentration of the at least one dopant material in the second electron-injecting layer is in the range of from 0.01% to 20% by volume.

11. The OLED of claim 1 wherein the device emits a red, green, blue, or white color.

12. An OLED display including a plurality of OLEDs according to claim 1 .

13. The OLED of claim 1 wherein the at least one organic host material in the first electron-injecting layer is a 8-hydroxy-quinoline derivative.