Organic electronic device having dual emitter dopants
View Patent ↗Electronic devices comprising an anode, buffer layer, hole transport layer, photoactive layer, electron transport layer, electron injection layer, and cathode are provided, where the photoactive layer comprises a dual dopant in a metallic complex. The dopants are selected so that their emitting wavelengths are essentially the same, while their ionization potentials and electron affinities are substantially different. The dual dopant device allows for tuning the ionization potential of one dopant to enhance hole injection and/or minimize hole trapping, while independently tuning the electron affinity of the other dopant to enhance electron injection and/or minimize electron trapping.
1. An electronic device comprising:
a hole transport layer having an ionization potential IP HT , and an electron affinity EA HT ,
a photoactive layer, and
an electron transport layer having an ionization potential IP ET , and an electron affinity EA ET ,
wherein the photoactive layer comprises:
a host having an ionization potential IP H and an electron affinity EA H ,
a first photoactive material having a peak wavelength λ1, an emission color with coordinates x1 and y1, an ionization potential IP P1 and an electron affinity EA P1 , and
a second photoactive material, having a peak wavelength λ2, an emission color with coordinates x2 and y2, an ionization potential IP P2 and an electron affinity EA P2 ;
wherein:
when λ1 is 570 to 650 nm:
λ1-λ2 is less than 20 nm, absolute value,
x1 and x2 are 0.6-0.7, and
y1 and y2 are 0.28-0.38;
when λ1 is 500 to 569 nm:
λ1-λ2 is less than 15 nm, absolute value,
x1 and x2 are 0.2-0.35, and
y1 and y2 are 0.58-0.75;
when λ1 is 440 to 499 nm:
λ1-λ2 is less than 10 nm, absolute value,
x1 and x2 are 0.1-0.2, and
y1 and y2 are 0.05-0.25,
and further wherein
IP P1 -IP P2 >0.1 eV, absolute value,
EA P1 -EA P2 >0.1 eV, absolute value.
2. A device of claim 1 wherein at least one of the following conditions is present, where eV values are expressed as absolute values:
(a) (IP P1 or IP P2 )−IP HT <0.5 eV
(b) (EA P1 or EA P2 )−EA HT <0.5 eV
(c) (IP P1 or IP P2 )−IP H <0.5 eV
(d) (EA P1 or EA P2 )−EA H <0.5 eV.
3. A device of claim 2 wherein (IP P1 or IP P2 )−IP HT <0.3 eV.
4. A device of claim 2 wherein (IP P1 or IP P2 )−IP HT <0.1 eV.
5. A device of claim 2 wherein (IP P1 or IP P2 )−IP H <0.3 eV.
6. A device of claim 2 wherein (IP P1 or IP P2 )−IP H <0.1 eV.
7. A device of claim 2 wherein (EA P1 or EA P2 )−EA H <0.3 eV.
8. A device of claim 2 wherein (EA P1 or EA P2 )−EA H <0.1 eV.
9. A device of claim 2 having the following structure, in order:
anode, buffer layer, hole transport layer, photoactive layer, electron transport layer, electron injection layer, cathode.
10. A device of claim 2 wherein the photoactive layer comprises Red 1 and Red 2 doped in a metallic complex, wherein:
11. A device of claim 10 wherein the metallic complex is Balq2:
12. A device of claim 1 wherein the ionization potentials of the first and second photoactive materials differ by at least 0.1 eV.
13. A device of claim 1 wherein the electron affinities of the first and second photoactive materials differ by at least 0.1 eV.
14. A device of claim 1 wherein the ionization potentials of the first and second photoactive materials differ by at least 0.1 eV and the electron affinities of the first and second photoactive materials differ by at least 0.1 eV.
15. A device of claim 1 wherein (EA P1 or EA P2 )−EA ET <0.5 eV.
16. A device of claim 1 having the following structure, in order:
anode, buffer layer, hole transport layer, photoactive layer, electron transport layer, electron injection layer, cathode.
17. A device of claim 1 wherein the photoactive layer comprises Red 1 and Red 2 doped in a metallic complex, wherein:
18. A device of claim 17 wherein the metallic complex is Balq2 wherein: