Organic electroluminescent element and electronic device

Patent metadata

Field	Value
Publication number	US-2020321540-A1
Application number	US-201716321642-A
Country	US
Kind code	A1
Filing date	Aug 9, 2017
Priority date	Aug 10, 2016
Publication date	Oct 8, 2020
Grant date	—

Abstract

An organic electroluminescence device includes an anode, an emitting layer, and a cathode. The emitting layer contains a first compound, a second compound, and a third compound. An ionization potential Ip1 of the first compound and an ionization potential Ip2 of the second compound satisfy a relationship represented by a numerical expression (Numerical Expression 1) below. The first compound is a delayed fluorescent compound. The second compound is a fluorescent compound. The third compound has an electron mobility of 1×10 −8 cm 2 /(V·s) or more.
0≤ Ip 2− Ip 1≤0.8 [eV]  (Numerical Expression 1)

First claim

1 . An organic electroluminescence device, comprising:
an anode; an emitting layer; and a cathode, wherein the emitting layer comprises a first compound, a second compound, and a third compound, an ionization potential Ip1 of the first compound and an ionization potential Ip2 of the second compound satisfy a relationship represented by a numerical expression:
0≤ Ip 2− Ip 1≤0.8 [eV],

the first compound is a delayed fluorescent compound, the second compound is a fluorescent compound, and the third compound has an electron mobility of 1×10 −8 cm 2 /(V·s) or more.

2 . The organic electroluminescence device according to claim 1 , wherein a difference ΔST(H) between a singlet energy S 1 (H) of the first compound and an energy gap T 77K (H) at 77[K] of the first compound satisfies a relationship;
Δ ST ( H )= S 1 ( H )− T 77K ( H )<0.3 [eV]  (Numerical Expression 2).

3 . The organic electroluminescence device according to claim 1 , wherein a difference ΔT(H−E) between an energy gap T 77K (H) at 77[K] of the first compound and an energy gap T 77K (E) at 77[K] of the third compound satisfies a relationship represented by a numerical expression:
Δ T ( H−E )= T 77K ( H )− T 77K ( E )≤0.6 [eV].

4 . The organic electroluminescence device according to claim 1 , wherein the ionization potential Ip1 of the first compound and the ionization potential Ip2 of the second compound satisfy a relationship represented by a numerical expression:
0≤ Ip 2− Ip 1≤0.75 [eV].

5 - 21 . (canceled)

22 . The organic electroluminescence device according to claim 1 , wherein a luminescence quantum efficiency of the first compound is 70% or less.

23 . The organic electroluminescence device according to claim 1 , wherein a luminescence quantum efficiency of the first compound is 30% or more.

24 . The organic electroluminescence device according to claim 1 , wherein a concentration of the third compound in the emitting layer is less than 50 mass %.

25 . The organic electroluminescence device according to claim 1 , wherein a concentration of the third compound in the emitting layer is 30 mass % or less.

26 . The organic electroluminescence device according to claim 1 , wherein the emitting layer comprises no metal complex.

27 . The organic electroluminescence device according to claim 1 , wherein the emitting layer comprises no phosphorescent metal complex.

28 . The organic electroluminescence device according to claim 1 , wherein an emission peak wavelength of the second compound is 550 nm or less.

29 . The organic electroluminescence device according to claim 1 , wherein a delayed fluorescence ratio exceeds 37.5%.

30 . An electronic device comprising the organic electroluminescence device according to claim 1 .

Assignees

• Idemitsu Kosan Co

Inventors

• Yoshizaki Kei
• Ogiwara Toshinari

Classifications

• H10K85/322

  comprising boron · CPC title

• H10K2101/20

  Delayed fluorescence emission · CPC title

• H10K85/6576

  comprising only sulfur in the heteroaromatic polycondensed ring system, e.g. benzothiophene · CPC title

• C09K11/06 Primary

  containing organic luminescent materials · CPC title

• H10K2101/10

  Triplet emission · CPC title