Organic light-emitting device and flat display apparatus including the same

1. An organic light-emitting device comprising:

a first electrode;

a second electrode facing the first electrode;

light-emitting units in a number of m between the first electrode and the second electrode; and

charge generation layers in a number of m−1 respectively between each pair of adjacent light-emitting units among the light-emitting units in the number of m, each charge generation layer comprising an n-type charge generation layer and a p-type charge generation layer,

wherein m is an integer of 3 or more,

the light-emitting units in the number of m each comprise a hole transport region, an emission layer, and an electron transport region, which are sequentially stacked,

the electron transport regions in a number of m comprised in the light-emitting units in the number of m each comprise an electron transport material, and

the electron transport materials in a number of m comprised in the electron transport regions in the number of m are each independently selected from a first compound, a second compound, and a third compound, and

the first compound is selected from Compounds 1 to 17, the second compound is selected from Compounds 101 to 120, and the third compound is represented by Formula 3:

and

wherein in Formula 3,

A 21 is a π electron-depleted nitrogen-containing ring,

L 21 is a substituted or unsubstituted C 5 -C 60 carbocyclic group or a substituted or unsubstituted C 1 -C 60 heterocyclic group,

a21 is an integer selected from 0 to 5,

Ar 21 is a substituted or unsubstituted C 5 -C 60 carbocyclic group or a substituted or unsubstituted C 1 -C 60 heterocyclic group,

b21 is an integer selected from 1 to 5,

c21 is an integer selected from 0 to 20,

at least one substituent selected from the substituted C 5 -C 60 carbocyclic group and the substituted C 1 -C 60 heterocyclic group is selected from:

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C 1 -C 60 alkyl group, a C 2 -C 60 alkenyl group, a C 2 -C 60 alkynyl group, and a C 1 -C 60 alkoxy group;

a C 1 -C 60 alkyl group, a C 2 -C 60 alkenyl group, a C 2 -C 60 alkynyl group, and a C 1 -C 60 alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 1 -C 10 heterocycloalkenyl group, a C 6 -C 60 aryl group, a C 6 -C 60 aryloxy group, a C 6 -C 60 arylthio group, a C 1 -C 60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —Si(Q 11 )(Q 12 )(Q 13 ), —B(Q 11 )(Q 12 ), —C(═O)(Q 11 ), —S(═O) 2 (Q 11 ), and —P(═O)(Q 11 )(Q 12 );

a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 1 -C 10 heterocycloalkenyl group, a C 6 -C 60 aryl group, a C 6 -C 60 aryloxy group, a C 6 -C 60 arylthio group, a C 1 -C 60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group;

a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 1 -C 10 heterocycloalkenyl group, a C 6 -C 60 aryl group, a C 6 -C 60 aryloxy group, a C 6 -C 60 arylthio group, a C 1 -C 60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono 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 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 1 -C 10 heterocycloalkenyl group, a C 6 -C 60 aryl group, a C 6 -C 60 aryloxy group, a C 6 -C 60 arylthio group, a C 1 -C 60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group, —Si(Q 21 )(Q 22 )(Q 23 ), —B(Q 21 )(Q 22 ), —C(═O)(Q 21 ), —S(═O) 2 (Q 21 ), and —P(═O)(Q 21 )(Q 22 ); and

—Si(Q 31 )(Q 32 )(Q 33 ), —B(Q 31 )(Q 32 ), —C(═O)(Q 31 ), —S(═O) 2 (Q 31 ), and —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 are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono 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 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 1 -C 10 heterocycloalkenyl group, a C 6 -C 60 aryl group, a C 1 -C 60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group, and

indicates a binding site to a neighboring atom.

2. The organic light-emitting device of claim 1 , wherein an m th electron transport region among the electron transport regions in the number of m is between an m th emission layer and the second electrode, and

an electron transport material comprised in the m th electron transport region is different from an electron transport material comprised in at least one electron transport region among the other electron transport regions.

3. The organic light-emitting device of claim 1 , wherein L 21 is selected from:

a benzene group, a pentalene group, an indene group, a naphthalene group, an azulene group, a heptalene group, an indacene group, an acenaphthalene group, a fluorene group, a spiro-bifluorene group, a spiro-benzofluorene-fluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pyrrole group, a thiophene group, a furan group, a silole group, an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyrimidine group, a pyridazine group, a triazine group, a benzofuran group, a benzothiophene group, a benzosilole group, a dibenzosilole group, a quinoline group, an isoquinoline group, a benzimidazole group, an imidazopyridine group, an imidazopyrimidine group, a carbazole group, a dibenzofuran group, a dibenzothiophene group, and a quinazoline group; and

a benzene group, a pentalene group, an indene group, a naphthalene group, an azulene group, a heptalene group, an indacene group, an acenaphthalene group, a fluorene group, a spiro-bifluorene group, a spiro-benzofluorene-fluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pyrrole group, a thiophene group, a furan group, a silole group, an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyrimidine group, a pyridazine group, a triazine group, a benzofuran group, a benzothiophene group, a benzosilole group, a dibenzosilole group, a quinoline group, an isoquinoline group, a benzimidazole group, an imidazopyridine group, an imidazopyrimidine group, a carbazole group, a dibenzofuran group, a dibenzothiophene group, and a quinazoline group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a C 1 -C 20 alkyl group, a C 1 -C 20 alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thienyl group, a furanyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a benzofuranyl group, a benzothienyl group, a silolyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a benzosilolyl group, a dibenzosilolyl group, —Si(Q 31 )(Q 32 )(Q 33 ), —N(Q 31 )(Q 32 ), and —B(Q 31 )(Q 32 ), wherein Q 31 to Q 33 are each independently selected from a C 1 -C 20 alkyl group, a C 1 -C 20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, and a pyridinyl group.

4. The organic light-emitting device of claim 1 , wherein Ar 21 is selected from:

a benzene group, a pentalene group, an indene group, a naphthalene group, an azulene group, a heptalene group, an indacene group, an acenaphthalene group, a fluorene group, a spiro-bifluorene group, a spiro-benzofluorene-fluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pyrrole group, a thiophene group, a furan group, a silole group, an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyrimidine group, a pyridazine group, a triazine group, a benzofuran group, a dibenzofuran group, a benzothiophene group, a benzosilole group, a dibenzosilole group, a quinoline group, an isoquinoline group, a quinazoline group, a benzimidazole group, an imidazopyridine group, and an imidazopyrimidine group; and

a benzene group, a pentalene group, an indene group, a naphthalene group, an azulene group, a heptalene group, an indacene group, an acenaphthalene group, a fluorene group, a spiro-bifluorene group, a spiro-benzofluorene-fluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pyrrole group, a thiophene group, a furan group, a silole group, an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyrimidine group, a pyridazine group, a triazine group, a benzofuran group, a dibenzofuran group, a benzothiophene group, a benzosilole group, a dibenzosilole group, a quinoline group, an isoquinoline group, a quinazoline group, a benzimidazole group, an imidazopyridine group, and an imidazopyrimidine group, each substituted with at least one selected from deuterium, —F, —CI, —Br, —I, a hydroxyl group, a cyano group, a C 1 -C 20 alkyl group, a C 1 -C 20 alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thienyl group, a furanyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a benzofuranyl group, a benzothienyl group, —Si(Q 31 )(Q 32 )(Q 33 ), —N(Q 31 )(Q 32 ), and —B(Q 31 )(Q 32 ),

wherein Q 31 to Q 33 are each independently selected from a C 1 -C 20 alkyl group, a C 1 -C 20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, and a pyridinyl group.

5. The organic light-emitting device of claim 1 , wherein A 21 is selected from a pyridine group, a pyrimidine group, a pyrazine group, a triazine group, an aziridine group, an imidazole group, an indole group, an isoindole group, a purine group, a quinoline group, a quinazoline group, a phenothiazine group, an acridine group, a phenazine group, a phenanthroline group, a carbazole group, an oxadiazole group, a triazole group, an imidazole group, and a benzimidazole group.

6. The organic light-emitting device of claim 1 , wherein

i) one electron transport material among the electron transport materials in the number of m is the second compound, and the other electron transport materials are the first compound;

ii) one electron transport material among the electron transport materials in the number of m is the first compound, and the other electron transport materials are the second compound;

iii) each of the electron transport materials in the number of m is the third compound, wherein one electron transport material among the electron transport materials comprises a triazine group, and the other electron transport materials comprise a carbazole group; or

iv) each of the electron transport materials in the number of m is the third compound, wherein one electron transport material among the electron transport materials comprises a carbazole group, and the other electron transport materials comprise a triazine group.

7. The organic light-emitting device of claim 1 , wherein an m th electron transport region among the electron transport regions in the number of m is between an m th emission layer and the second electrode, and

an absolute value of a lowest unoccupied molecular orbital energy level of the m th electron transport region is in a range between an absolute value of a lowest unoccupied molecular orbital energy level of a host comprised in the m th emission layer and an absolute value of a work function of an inorganic material comprised in the second electrode.

8. The organic light-emitting device of claim 7 , wherein the absolute value of the lowest unoccupied molecular orbital energy level of the m th electron transport region and the absolute value of the lowest unoccupied molecular orbital energy level of the host satisfy Equation 1:

∥ E LUMO_ETL(m) |−|E LUMO_Host ∥≤0.2 eV.  Equation 1

wherein, in Equation 1, |E LUMO_ETL(m) | is the absolute value of the lowest unoccupied molecular orbital energy level of the m th electron transport region, and |E Lumo_Host | the absolute value of the lowest unoccupied molecular orbital energy level of the host.

9. The organic light-emitting device of claim 1 , wherein an n th charge generation layer among the charge generation layers in the number of m−1 is between an electron transport region of an n th light-emitting unit and a hole transport region of an (n+1) th light-emitting unit among the light-emitting units in the number of m, and

n is an integer selected from 1 to m−1.

10. The organic light-emitting device of claim 9 , wherein an absolute value of a lowest unoccupied molecular orbital energy level of the electron transport region of the n th light-emitting unit and an absolute value of a lowest unoccupied molecular orbital energy level of the n th charge generation layer satisfy Equation 2:

∥ E LUMO_ETL(n) |−|E LUMO_CGL(n) ∥≤0.15 eV.  Equation 2

wherein, in Equation 2, |E LUMO_ETL(n) | is the absolute value of the lowest unoccupied molecular orbital energy level of the electron transport region of the nthlight-emitting unit, and |E Lumo_CGL(n) | is the absolute value of the lowest unoccupied molecular orbital energy level of the n th charge generation layer.

11. The organic light-emitting device of claim 1 , wherein the hole transport regions in a number of m among the light-emitting units in the number of m each independently comprise a hole injection layer, a hole transport layer, an electron blocking layer, or any combination thereof, and

the electron transport regions in the number of m each independently comprise a hole blocking layer, an electron transport layer, an electron injection layer, a buffer layer, or any combination thereof.

12. The organic light-emitting device of claim 1 , wherein m is 3 or 4.

13. The organic light-emitting device of claim 1 , wherein

the first electrode is an anode,

the second electrode is a cathode,

the organic light-emitting device further comprises:

an m th light-emitting unit between the first electrode and the second electrode;

an (m−1) th light-emitting unit between the first electrode and the m th light-emitting unit; and

an (m−1) th charge generation layer between the m th light-emitting unit and the (m−1) th light-emitting unit,

the m th light-emitting unit comprises an m th emission layer,

the (m−1) th light-emitting unit comprises an (m−1) th emission layer,

the organic light-emitting device further comprises an (m−1) th hole transport region between the first electrode and the (m−1) th emission layer, the organic light-emitting device further comprises an (m−1) th electron transport region between the (m−1) th emission layer and the (m−1) th charge generation layer,

the organic light-emitting device further comprises an m th hole transport region between the (m−1) th charge generation layer and the m th emission layer,

the organic light-emitting device further comprises an m th electron transport region between the m th emission layer and the second electrode,

an electron transport material comprised in the m th electron transport region is different from the electron transport material comprised in the (m−1) th electron transport region,

the (m−1) th and m th hole transport regions each comprise a hole injection layer, a hole transport layer, an electron blocking layer, or any combination thereof, and

the (m−1) th and m th electron transport regions each comprise a hole blocking layer, an electron transport layer, an electron injection layer, a buffer layer, or any combination thereof.

14. The organic light-emitting device of claim 1 , wherein the light-emitting units in the number of m are to emit blue light having a maximum emission wavelength of about 440 nm or more and about 490 nm or less.

15. A flat display apparatus comprising: a thin-film transistor comprising a source electrode, a drain electrode, and an activation layer; and the organic light-emitting device of claim 1 ,

wherein the first electrode of the organic light-emitting device is in electrical connection with one of the source electrode and the drain electrode of the thin-film transistor.