Highly efficient OLED devices with very short decay times

1. An organic light-emitting device comprising

(a) an anode,

(i) a cathode, and

(e) an emitting layer between the anode and cathode, comprising

2 to 40% by weight of a luminescent organometallic complex X having a difference of the singlet energy (E S1 (X)) and the triplet energy (E T1 (X)) of smaller than 0.2 eV,

0.05 to 5.0% by weight of a fluorescent emitter Y, and

55 to 97.95% by weight of a host compound(s),

wherein the amount of the luminescent organometallic complex X, the fluorescent emitter Y and the host compound(s) does not exceed a total of 100% by weight, and

wherein the singlet energy of the luminescent organometallic complex X (E S1 (X)) is greater than the singlet energy of the fluorescent emitter Y (E S1 (Y)).

2. The organic light-emitting device according to claim 1 , wherein the difference of the singlet energy and the triplet energy of the luminescent organometallic complex X is smaller than 0.1 eV.

3. The organic light-emitting device according to claim 1 , wherein the difference of the singlet energy and the triplet energy of the luminescent organometallic complex X is smaller than 0.05 eV.

4. The organic light-emitting device according to claim 1 , wherein the emissive lifetime τ 0 , which is calculated by τ 0 =τ v /QY, of thin films consisting of the luminescent organometallic complex X, fluorescent emitter Y and host compound(s) is below 100 ns.

5. The organic light-emitting device according to claim 1 , wherein the luminescent organometallic complex X is a luminescent iridium complex.

6. The organic light-emitting device according to claim 5 , wherein the luminescent iridium complex is a compound of formulae

7. The organic light-emitting device according to claim 5 , wherein the luminescent iridium complex is a compound of formulae

wherein X and Y are independently of each other CH, or N, with the proviso that at least one of X and Y is N;

R 23 , R 24 , R 27 and R 28 are each independently hydrogen, deuterium, methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, sec-butyl, iso-butyl, cyclopentyl, cyclohexyl, OCH 3 , OCF 3 , phenyl, pyridyl, primidyl, pyrazinyl, carbazolyl, dibenzofuranyl, dibenzothiophenyl, benzofuranyl and benzothiophenyl, wherein the aforementioned radicals may be unsubstituted or substituted by methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, sec-butyl, iso-butyl, methoxy, CF 3 or phenyl, a group with donor or acceptor action, selected from F, CF 3 , CN and SiPh 3 ; and

R 25 is methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, sec-butyl, iso-butyl, cyclopentyl, cyclohexyl, OCH 3 , OCF 3 , phenyl, pyridyl, primidyl, pyrazinyl, wherein the aforementioned radicals may be substituted by, preferably monosubstituted, by methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, sec-butyl, iso-butyl, methoxy or phenyl or unsubstituted; a group with donor or acceptor action selected from CF 3 and CN.

8. The organic light-emitting device according to claim 1 , wherein the luminescent organometallic complex X is a luminescent copper complex.

9. The organic light-emitting device according to claim 8 , wherein the luminescent copper complex is a compound of formulae

10. The organic light-emitting device according to claim 1 , wherein the fluorescent emitter Y is a compound of formulae

11. The organic light-emitting device according to claim 1 , wherein the host compound is a compound of formulae

wherein T is O, or S.

12. The organic light-emitting device according to claim 11 , wherein the host compound is a compound of formulae

13. The organic light-emitting device according to claim 1 , comprising in this order:

(a) an anode,

(b) optionally a hole injection layer,

(c) a hole transport layer,

(d) exciton blocking layer

(e) an emitting layer, comprising the luminescent organometallic complex X the fluorescent emitter Y and the host compound(s),

(f) a hole/exciton blocking layer

(g) an electron transport layer,

(h) optionally an electron injection layer, and

(i) a cathode.

14. An emitting layer, comprising

2 to 40% by weight of a luminescent organometallic complex X having a difference of the singlet energy and the triplet energy of smaller than 0.2 eV,

0.05 to 5% by weight of a fluorescent emitter Y and

55 to 97.95% by weight of a host compound(s),

wherein the amount of the organometallic complex X, the fluorescent emitter Y and the host compound(s) does not exceed a total of 100% by weight and the singlet energy of the luminescent organometallic complex X (E S1 (X)) is greater than the singlet energy of the fluorescent emitter Y (E S1 (Y)).

15. An apparatus selected from the group consisting of stationary visual display units such as visual display units of computers, televisions, visual display units in printers, kitchen appliances and advertising panels, illuminations, information panels, and mobile visual display units such as visual display units in cellphones, laptops, digital cameras, MP3 players, vehicles and destination displays on buses and trains; illumination units; keyboards; items of clothing; furniture; wallpaper, comprising the organic light-emitting device according to claim 1 .

16. An apparatus selected from the group consisting of stationary visual display units such as visual display units of computers, televisions, visual display units in printers, kitchen appliances and advertising panels, illuminations, information panels, and mobile visual display units such as visual display units in cellphones, laptops, digital cameras, MP3 players, vehicles and destination displays on buses and trains; illumination units; keyboards; items of clothing; furniture; wallpaper, comprising the emitting layer of claim 14 .

17. A light-emitting electrochemical cell (LEEC), organic light emitting device (OLED) sensor, an organic solar cell (OSC), an organic field-effect transistor, an organic diode and an organic photodiode, comprising the emitting layer of claim 14 .