Light-emitting device and electronic apparatus including same
A light-emitting device includes: a first electrode; a second electrode; m emission units between the first electrode and the second electrode; and m−1 charge generation layer(s), each located between two adjacent emission units, and including m−1 n-type charge generation layer(s) and m−1 p-type charge generation layer(s). The m emission units each include a hole transport region, an emission layer, and an electron transport region. A first hole transport region in a first emission unit closest to the first electrode may include a hole transfer layer and a hole injection layer and/or a hole transport layer. The hole transfer layer may be a single layer consisting of an electron-transporting compound including a phosphine oxide group (P═O), a phosphine sulfide group (P═S), a π electron-deficient nitrogen-containing C 1 -C 60 cyclic group, or any combination thereof. A highest occupied molecular orbital (HOMO) energy level of the hole transfer layer may be about −6.0 eV to about −5.3 eV.
1. A light-emitting device comprising:
a first electrode;
a second electrode facing the first electrode;
m emission units located between the first electrode and the second electrode; and
m−1 charge generation layer(s), each located between two adjacent emission units among the m emission units, and comprising m−1 n-type charge generation layer(s) and m−1 p-type charge generation layer(s),
wherein m is an integer of 2 or greater,
the m emission units each comprise a hole transport region, an emission layer, and an electron transport region, which are sequentially arranged,
a first hole transport region in a first emission unit closest among the m emission units to the first electrode comprises a hole transfer layer and at least one of a hole injection layer or a hole transport layer, which are sequentially arranged between the first electrode and a first emission layer in the first emission unit,
the hole transfer layer is a single layer consisting of an electron-transporting compound,
the electron-transporting compound comprises a phosphine oxide group (P═O), a phosphine sulfide group (P═S), a π electron-deficient nitrogen-containing C 1 -C 60 cyclic group, or any combination thereof, and
a highest occupied molecular orbital (HOMO) energy level of the hole transfer layer is about −6.0 electron volts (eV) to about −5.3 eV.
2. The light-emitting device of claim 1 , wherein m is an integer of 3 or greater.
3. The light-emitting device of claim 1 , wherein the electron-transporting compound is represented by Formula 1 or Formula 2:
[Ar 1 ] a1 -[(L 1 ) b1 -R 1 ] c1 Formula 1
[Ar 2 ] a2 -[(L 2 ) b2 -R 2 ] c2 , and Formula 2
wherein, in Formulae 1 and 2,
Ar 1 , Ar 2 , L 1 , and L 2 are each independently a C 3 -C 60 carbocyclic group unsubstituted or substituted with at least one R 10a or a C 1 -C 60 heterocyclic group unsubstituted or substituted with at least one R 10a ,
a1 and a2 are each independently 1, 2, or 3,
b1 and b2 are each independently 0, 1, 2, 3, 4, or 5,
R 1 and R 2 are each independently a C 3 -C 60 carbocyclic group unsubstituted or substituted with at least one R 10a , a C 1 -C 60 heterocyclic group unsubstituted or substituted with at least one R 10a , —Si(Q 1 )(Q 2 )(Q 3 ), —C(═O)(Q 1 ), —S(═O) 2 (Q 1 ), —P(═O)(Q 1 )(Q 2 ), or —P(═S)(Q 1 )(Q 2 ),
c1 and c2 are each independently 1, 2, 3, 4, or 5,
at least one of Ar 1 , L 1 , or R 1 is independently a π electron-deficient nitrogen-containing C 1 -C 60 cyclic group unsubstituted or substituted with at least one R 10a , and
at least one R 2 group is —P(═O)(Q 1 )(Q 2 ) or —P(═S)(Q 1 )(Q 2 ),
wherein R 10a is deuterium (-D), —F, —C 1 , —Br, —I, a hydroxyl group, a cyano group, or a nitro group;
a C 1 -C 60 alkyl group, a C 2 -C 60 alkenyl group, a C 2 -C 60 alkynyl group, or a C 1 -C 60 alkoxy group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C 3 -C 60 carbocyclic group, a C 1 -C 60 heterocyclic group, a C 6 -C 60 aryloxy group, a C 6 -C 60 arylthio group, —Si(Q 11 )(Q 12 )(Q 13 ), —N(Q 11 )(Q 12 ), —B(Q 11 )(Q 12 ), —C(═O)(Q 11 ), —S(═O) 2 (Q 11 ), —P(═O)(Q 11 )(Q 12 ), or any combination thereof;
a C 3 -C 60 carbocyclic group, a C 1 -C 60 heterocyclic group, a C 6 -C 60 aryloxy group, or a C 6 -C 60 arylthio group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C 1 -C 60 alkyl group, a C 2 -C 60 alkenyl group, a C 2 -C 60 alkynyl group, a C 1 -C 60 alkoxy group, a C 3 -C 60 carbocyclic group, a C 1 -C 60 heterocyclic group, a C 6 -C 60 aryloxy group, a C 6 -C 60 arylthio group, —Si(Q 21 )(Q 22 )(Q 23 ), —N(Q 21 )(Q 22 ), —B(Q 21 )(Q 22 ), —C(═O)(Q 21 ), —S(═O) 2 (Q 21 ), —P(═O)(Q 21 )(Q 22 ), or any combination thereof; or
—Si(Q 31 )(Q 32 )(Q 33 ), —N(Q 31 )(Q 32 ), —B(Q 31 )(Q 32 ), —C(═O)(Q 31 ), —S(═O) 2 (Q 31 ), or —P(═O)(Q 31 )(Q 32 )
Q 1 to Q 3 , Q 11 to Q 13 , Q 21 to Q 23 , and Q 31 to Q 33 may each independently be hydrogen; deuterium; —F; —Cl; —Br; —I; a hydroxyl group; a cyano group; a nitro group; a C 1 -C 60 alkyl group; a C 2 -C 60 alkenyl group; a C 2 -C 60 alkynyl group; a C 1 -C 60 alkoxy group; or a C 3 -C 60 carbocyclic group or a C 1 -C 60 heterocyclic group, each unsubstituted or substituted with deuterium, —F, a cyano group, a C 1 -C 60 alkyl group, a C 1 -C 60 alkoxy group, a phenyl group, a biphenyl group, or any combination thereof.
4. The light-emitting device of claim 3 , wherein at least one of Ar 1 , L 1 , or R 1 is independently selected from:
a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, and a triazine group; and
a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, and a triazine group, each substituted with at least one R 10a .
5. The light-emitting device of claim 3 , wherein at least one of Ar 2 , L 2 , or R 2 is independently a π electron-rich C 3 -C 60 cyclic group unsubstituted or substituted with at least one R 10a .
6. The light-emitting device of claim 1 , wherein a difference between a HOMO energy level of the hole transfer layer and a HOMO energy level of the hole injection layer or hole transport layer adjacent to the hole transfer layer, is 0.15 eV or greater.
7. The light-emitting device of claim 1 , wherein the first emission layer comprises a compound represented by Formula 3:
[Ar 3 ] a3 -[(L 3 ) b3 -R 3 ] c3 , and Formula 3
wherein, in Formula 3,
Ar 3 and L 3 are each independently a C 3 -C 60 carbocyclic group unsubstituted or substituted with at least one R 10a or a C 1 -C 60 heterocyclic group unsubstituted or substituted with at least one R 10a ,
a3 is 1, 2, or 3,
b3 is an integer from 0 to 5,
R 3 is hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C 1 -C 60 alkyl group unsubstituted or substituted with at least one R 10a , a C 2 -C 60 alkenyl group unsubstituted or substituted with at least one R 10a , a C 2 -C 60 alkynyl group unsubstituted or substituted with at least one R 10a , a C 1 -C 60 alkoxy group unsubstituted or substituted with at least one R 10a , a C 3 -C 60 carbocyclic group unsubstituted or substituted with at least one R 10a , a C 1 -C 60 heterocyclic group unsubstituted or substituted with at least one R 10a , Si(Q 1 )(Q 2 )(Q 3 ), —N(Q 1 )(Q 2 ), —B(Q 1 )(Q 2 ), —C(═O)(Q 1 ), —S(═O) 2 (Q 1 ), or —P(═O)(Q 1 )(Q 2 ),
wherein Q 1 to Q 3 are each independently hydrogen; deuterium; —F; —C 1 ; —Br; —I; a hydroxyl group; a cyano group; a nitro group; a C 1 -C 60 alkyl group; a C 2 -C 60 alkenyl group; a C 2 -C 60 alkynyl group; a C 1 -C 60 alkoxy group: or a C 3 -C 60 carbocyclic group or a C 1 -C 60 heterocyclic group, each unsubstituted or substituted with deuterium, —F, a cyano group, a C 1 -C 60 alkyl group, a C 1 -C 60 alkoxy group, a phenyl group, a biphenyl group, or any combination thereof,
c3 is an integer from 1 to 5, and
at least one of Ar 3 , L 3 , or R 3 is independently a C 3 -C 60 carbocyclic group unsubstituted or substituted with at least one R 10a ,
wherein R 10a is:
deuterium (-D), —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, or a nitro group;
a C 1 -C 60 alkyl group, a C 2 -C 60 alkenyl group, a C 2 -C 60 alkynyl group, or a C 1 -C 60 alkoxy group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C 3 -C 60 carbocyclic group, a C 1 -C 60 heterocyclic group, a C 6 -C 60 aryloxy group, a C 6 -C 60 arylthio group, —Si(Q 11 )(Q 12 )(Q 13 ), —N(Q 11 )(Q 12 ), —B(Q 11 )(Q 12 ), —C(═O)(Q 1 ), —S(═O) 2 (Q 11 ), —P(═O)(Q 11 )(Q 12 ), or any combination thereof;
a C 3 -C 60 carbocyclic group, a C 1 -C 60 heterocyclic group, a C 6 -C 60 aryloxy group, or a C 6 -C 60 arylthio group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C 1 -C 60 alkyl group, a C 2 -C 60 alkenyl group, a C 2 -C 60 alkynyl group, a C 1 -C 60 alkoxy group, a C 3 -C 60 carbocyclic group, a C 1 -C 60 heterocyclic group, a C 6 -C 60 aryloxy group, a C 6 -C 60 arylthio group, —Si(Q 21 )(Q 22 )(Q 23 ), —N(Q 21 )(Q 22 ), —B(Q 21 )(Q 22 ), —C(═O)(Q 21 ), —S(═O) 2 (Q 21 ), —P(═O)(Q 21 )(Q 22 ), or any combination thereof; or
—Si(Q 31 )(Q 32 )(Q 33 ), —N(Q 31 )(Q 32 ), —B(Q 31 )(Q 32 ), —C(═O)(Q 31 ), —S(═O) 2 (Q 31 ), or —P(═O)(Q 31 )(Q 32 ), and
wherein Q 11 to Q 13 , Q 21 to Q 23 , and Q 31 to Q 33 may each independently be hydrogen; deuterium; —F; —Cl; —Br; —I; a hydroxyl group; a cyano group; a nitro group; a C 1 -C 60 alkyl group; a C 2 -C 60 alkenyl group; a C 2 -C 60 alkynyl group; a C 1 -C 60 alkoxy group; or a C 3 -C 60 carbocyclic group or a C 1 -C 60 heterocyclic group, each unsubstituted or substituted with deuterium, —F, a cyano group, a C 1 -C 60 alkyl group, a C 1 -C 60 alkoxy group, a phenyl group, a biphenyl group, or any combination thereof.
8. The light-emitting device of claim 1 , wherein the first emission unit further comprises an electron blocking layer between the hole injection layer or the hole transport layer and the first emission layer.
9. The light-emitting device of claim 8 , wherein the electron blocking layer comprises a material having a higher triplet energy level than a triplet energy level of a compound comprised in the first emission layer.
10. The light-emitting device of claim 1 , wherein m−1 hole transport region(s), excluding the first hole transport region in the first emission unit, do not comprise a hole transfer layer.
11. The light-emitting device of claim 1 , wherein m−1 hole transport region(s), excluding the first hole transport region in the first emission unit, each independently comprise a hole injection layer, a hole transport layer, an electron blocking layer, or any combination thereof, and
the m electron transport regions each independently comprise a hole blocking layer, an electron transport layer, an electron injection layer, a buffer layer, or any combination thereof.
12. The light-emitting device of claim 1 , wherein
the m emission units are to emit blue light having a maximum emission wavelength of about 440 nanometers (nm) to about 510 nm.
13. The light-emitting device of claim 1 , wherein
m emission layers comprised in the m emission units each independently comprise a phosphorescent dopant, a fluorescent dopant, a delayed fluorescence material, or any combination thereof.
14. The light-emitting device of claim 1 , wherein
a ratio of a delayed fluorescence component to a sum of a fluorescence component and a delayed fluorescence component from measurement of transient electroluminescence (EL) of the light-emitting device is 30 percent (%) or higher.
15. The light-emitting device of claim 1 , wherein the first electrode has a work function of about −5.2 eV to about −4.8 eV.
16. The light-emitting device of claim 1 , further comprising a first capping layer outside the first electrode and a second capping layer outside the second electrode, wherein at least one of the first capping layer or the second capping layer comprises a material having a refractive index of 1.6 or higher at a wavelength of 589 nm.
17. An electronic apparatus comprising the light-emitting device of claim 1 .
18. The electronic apparatus of claim 17 , wherein a color-coordinate measured at a front viewing angle of the electronic apparatus is about 0.09 to about 0.15.
19. The electronic apparatus of claim 17 , further comprising: an encapsulation unit on the light-emitting device; and
a functional layer on the encapsulation unit, wherein the functional layer comprises a touchscreen layer, a polarization layer, a color filter, a color-conversion layer, or any combination thereof.
20. The electronic apparatus of claim 17 , comprising quantum dots or an optical member comprising the quantum dots, located on at least one traveling direction of light emitted from the light-emitting device.