LIGHT-EMITTING DEVICE AND ELECTRONIC APPARATUS INCLUDING THE SAME

1 . A light-emitting device comprising:

a first electrode;

a second electrode; and

an interlayer arranged between the first electrode and the second electrode and comprising an emission layer,

wherein the emission layer comprises a first compound represented by Formula 1 and a second compound represented by Formula 2:

wherein, in Formulae 1, 1A, and 2,

CY 11 and CY 12 are each independently a C 5 -C 30 carbocyclic group,

CY 13 to CY 16 , CY 23 , and CY 24 are each independently a C 5 -C 30 carbocyclic group or a C 1 -C 30 heterocyclic group,

Y 11 is O, S, or Se,

X 21 is N or C(R 21a ), X 22 is N or C(R 22a ), and X 23 is N or C(R 23a ),

at least one of X 21 to X 23 is N,

L 21 and L 22 are each independently a single bond, a substituted or unsubstituted C 3 -C 60 carbocyclic group, or a substituted or unsubstituted C 1 -C 60 heterocyclic group,

n21 and n22 are each independently an integer from 1 to 5,

T 13 and T 14 are each independently a group represented by Formula 1A,

a13 and a14 are each independently an integer from 0 to 10,

the sum of a13 and a14 is 1 or more,

R 11 and R 12 are each independently hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 1 -C 60 alkylthio group, a substituted or unsubstituted C 3 -C 10 cycloalkyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkyl group, a substituted or unsubstituted C 3 -C 10 cycloalkenyl group, a substituted or unsubstituted C 2 -C 10 heterocycloalkenyl group, a substituted or unsubstituted C 6 -C 60 aryloxy group, a substituted or unsubstituted C 6 -C 60 arylthio group, a substituted or unsubstituted C 1 -C 60 heteroaryl group, a substituted or unsubstituted C 1 -C 60 heteroaryloxy group, a substituted or unsubstituted C 1 -C 60 heteroarylthio group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q 1 )(Q 2 )(Q 3 ), —Ge(Q 1 )(Q 2 )(Q 3 ), —N(Q 4 )(Q 5 ), —B(Q 6 )(Q 7 ), or —P(═O)(Q 8 )(Q 9 ),

R 13 to R 16 , R 21 to R 24 , R 21a , R 22a , and R 23a are each independently hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 1 -C 60 alkylthio group, a substituted or unsubstituted C 3 -C 10 cycloalkyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkyl group, a substituted or unsubstituted C 3 -C 10 cycloalkenyl group, a substituted or unsubstituted C 2 -C 10 heterocycloalkenyl group, a substituted or unsubstituted C 6 -C 60 aryl group, a substituted or unsubstituted C 6 -C 60 aryloxy group, a substituted or unsubstituted C 6 -C 60 arylthio group, a substituted or unsubstituted C 1 -C 60 heteroaryl group, a substituted or unsubstituted C 1 -C 60 heteroaryloxy group, a substituted or unsubstituted C 1 -C 60 heteroarylthio group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q 1 )(Q 2 )(Q 3 ), —Ge(Q 1 )(Q 2 )(Q 3 ), —N(Q 4 )(Q 5 ), —B(Q 6 )(Q 7 ), or —P(═O)(Q 8 )(Q 9 ),

at least one of R 11 in the number of b11, R 12 in the number of b12, R 13 in the number of b13, R 14 in the number of b14, R 15 in the number of b15, and R 16 in the number of b16 is deuterium,

b11 to b16 and b21 to b24 are each independently an integer from 1 to 10,

* indicates a binding site to a neighboring atom,

at least one substituent of the substituted C 5 -C 30 carbocyclic group, the substituted C 1 -C 30 heterocyclic group, the substituted C 1 -C 60 alkyl group, the substituted C 2 -C 60 alkenyl group, the substituted C 2 -C 60 alkynyl group, the substituted C 1 -C 60 alkoxy group, the substituted C 1 -C 60 alkylthio group, the substituted C 3 -C 10 cycloalkyl group, the substituted C 1 -C 10 heterocycloalkyl group, the substituted C 3 -C 10 cycloalkenyl group, the substituted C 2 -C 10 heterocycloalkenyl group, the substituted C 6 -C 60 aryl group, the substituted C 6 -C 60 aryloxy group, the substituted C 6 -C 60 arylthio group, the substituted C 1 -C 60 heteroaryl group, the substituted C 1 -C 60 heteroaryloxy group, the substituted C 1 -C 60 heteroarylthio group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group is

deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, 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;

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 substituted with deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 2 -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 C 1 -C 60 heteroaryloxy group, a C 1 -C 60 heteroarylthio group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —Si(Q 11 )(Q 12 )(Q 13 ), —Ge(Q 11 )(Q 12 )(Q 13 ), —N(Q 14 )(Q 18 ), —B(Q 16 )(Q 17 ), —P(═O)(Q 18 )(Q 19 ), or any combination thereof;

a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 2 -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 C 1 -C 60 heteroaryloxy group, a C 1 -C 60 heteroarylthio group, a monovalent non-aromatic condensed polycyclic group, or a monovalent non-aromatic condensed heteropolycyclic group;

a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 2 -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, or a monovalent non-aromatic condensed heteropolycyclic group, each substituted with deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, 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 2 -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 C 1 -C 60 heteroaryloxy group, a C 1 -C 60 heteroarylthio group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —Si(Q 21 )(Q 22 )(Q 23 ), —Ge(Q 21 )(Q 22 )(Q 23 ), —N(Q 24 )(Q 25 ), —B(Q 26 )(Q 27 ), —P(═O)(Q 28 )(Q 29 ), or any combination thereof; or

—Si(Q 31 )(Q 32 )(Q 33 ), —Ge(Q 31 )(Q 32 )(Q 33 ), —N(Q 34 )(Q 35 ), —B(Q 36 )(Q 37 ), or —P(═O)(Q 38 )(Q 39 ), and

Q 1 to Q 9 , Q 11 to Q 19 , Q 21 to Q 29 , and Q 31 to Q 39 are each independently hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 3 -C 10 cycloalkyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkyl group, a substituted or unsubstituted C 3 -C 10 cycloalkenyl group, a substituted or unsubstituted C 2 -C 10 heterocycloalkenyl group, a substituted or unsubstituted C 6 -C 60 aryl group, a substituted or unsubstituted C 6 -C 60 aryloxy group, a substituted or unsubstituted C 6 -C 60 arylthio group, a substituted or unsubstituted C 1 -C 60 heteroaryl group, a substituted or unsubstituted C 1 -C 60 heteroaryloxy group, a substituted or unsubstituted C 1 -C 60 heteroarylthio group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, or a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group.

2 . The light-emitting device of claim 1 , wherein CY 11 and CY 12 are each independently a benzene group or a naphthalene group, and

CY 13 to CY 16 , CY 23 , and CY 24 are each independently a benzene group, a naphthalene group, or a pyridine group.

3 . The light-emitting device of claim 1 , wherein Formula 1 is represented by one of Formulae 1(1)-1 to 1(1)-4:

wherein, in Formulae 1(1)-1 to 1(1)-4,

CY 11 , CY 13 , CY 14 , Y 11 , T 13 , T 14 , a13, a14, R 11 to R 14 , b11, b13, and b14 are each as defined in claim 1 , and

d12 is an integer from 1 to 3.

4 . The light-emitting device of claim 1 , wherein a moiety represented by

in Formula 1 is a group represented by one of Formulae 1(2)-1 to 1(2)-4:

wherein, in Formulae 1(2)-1 to 1(2)-4,

R 13 and R 14 are each as defined in claim 1 ,

d13 is an integer from 1 to 4, and d14 is an integer from 1 to 3,

T 15 is defined as in connection with T 14 in claim 1 , and

* indicates a binding site to a neighboring atom.

5 . The light-emitting device of claim 1 , wherein Formula 1A is a group represented by one of Formulae 1A-1 to 1A-5:

wherein, in Formulae 1A-1 to 1A-5,

R 15 and R 16 are each as defined in claim 1 ,

R 17 and R 18 are each independently defined as in connection with R 15 in claim 1 ,

d15 and d16 are each independently an integer from 1 to 4,

d18 is an integer from 1 to 8, and

e16 is an integer from 1 to 3.

6 . The light-emitting device of claim 1 , wherein the sum of a13 and a14 is 1.

7 . The light-emitting device of claim 1 , wherein R 11 and R 12 are each independently:

hydrogen, deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , 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;

a group represented by one of Formulae 9-1 to 9-61, 9-201 to 9-240, 10-1 to 10-11, 10-211 to 10-304, 10-315 to 10-345, and 10-347 to 10-354; or

—Si(Q 1 )(Q 2 )(Q 3 ), —Ge(Q 1 )(Q 2 )(Q 3 ), or —N(Q 4 )(Q 5 ),

R 13 to R 16 , R 21 to R 24 , R 21a , R 22a , and R 23a are each independently

hydrogen, deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , 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;

a group represented by one of Formulae 9-1 to 9-61, 9-201 to 9-240, 10-1 to 10-129, and 10-201 to 10-354; or

—Si(Q 1 )(Q 2 )(Q 3 ), —Ge(Q 1 )(Q 2 )(Q 3 ), or —N(Q 4 )(Q 5 ), and

Q 1 to Q 5 are each as defined in claim 1

wherein, in Formulae 9-1 to 9-61, 9-201 to 9-240, 10-1 to 10-129, and 10-201 to 10-354, * indicates a binding site to a neighboring atom, “Ph” represents a phenyl group, “TMS” represents a trimethylsilyl group, “TMG” represents a trimethylgermyl group, and “t-Bu” represents a t-butyl group.

8 . The light-emitting device of claim 1 , wherein the first compound is represented by one of Formulae 1-1 to 1-16:

wherein, in Formulae 1-1 to 1-16,

CY 11 , CY 13 , Y 11 , R 11 to R 14 , b11, b13, T 13 , and a13 are each as defined in claim 1 ,

T 15 is defined as in connection with T 14 in claim 1 ,

d12 is an integer from 1 to 3, and

d14 is an integer from 1 to 3.

9 . The light-emitting device of claim 1 , wherein X 21 to X 23 are each N.

10 . The light-emitting device of claim 1 , wherein L 21 and L 22 are each independently: a single bond; or a group represented by one of Formulae L-1 to L-12

wherein, in Formulae L-1 to L-12,

Z 1 to Z 4 are each independently defined as in connection with R 21 in claim 1 ,

c1, c2, and c3 are each independently an integer from 1 to 4,

c4 is an integer from 1 to 3, and

* and *′ each indicate a binding site to a neighboring atom.

11 . The light-emitting device of claim 1 , wherein R 21 and R 22 are each independently a C 6 -C 60 aryl group unsubstituted or substituted with at least one R 10a , a group represented by Formula 2A, or a group represented by Formula 2B, and

R 10a is defined as in connection with R 23 in claim 1 :

wherein, in Formulae 2A and 2B,

R 25 , R 26 , and Z 21 to Z 25 are each defined as in connection with R 23 in claim 1 ,

d25 and d26 are each independently an integer from 1 to 4,

c21 to c25 are each independently an integer from 1 to 5,

L 23 is defined as in connection with L 21 in claim 1 ,

n23 is an integer from 1 to 5,

m23 is an integer from 0 to 3, and

* indicates a binding site to a neighboring atom.

12 . The light-emitting device of claim 1 , wherein the first compound is a compound selected from Compounds H1 to H32 in which at least one hydrogen atom is substituted with a deuterium atom, and

the second compound is one of Compounds E1 to E39:

13 . The light-emitting device of claim 1 , wherein the emission layer further comprises a third compound, a fourth compound, or any combination thereof,

the third compound comprises a transition metal, and

a difference between a triplet energy level and a singlet energy level of the fourth compound is equal to or less than 0.4 eV.

14 . The light-emitting device of claim 13 , wherein the third compound comprises an organometallic compound represented by Formula 3 or Formula 5:

wherein, in Formula 3,

M 31 is a transition metal,

X 31 to X 34 are each independently C or N,

two bonds of a bond between X 31 and M 31 , a bond between X 32 and M 31 , a bond between X 33 and M 31 , and a bond between X 34 and M 31 are each a coordinate bond, and the other two bonds are each a covalent bond,

CY 31 to CY 34 are each independently a C 5 -C 30 carbocyclic group or a C 1 -C 30 heterocyclic group,

L 31 is a single bond, a double bond, *—N(R 35a )—*′, *—B(R 35a )—*′, *—P(R 35a )—*′, *—C(R 35a )(R 35b )—*′, *—Si(R 35a )(R 35b )*′, *—Ge(R 35a )(R 35b )—*′, *—S—*′, *—Se—*′, *—O—*′, *—C(═O)*′, *—S(═O)—*′, *—S(═O) 2 —*′, *—C(R 35a )═*′, *═C(R 35a )—*′, *—C(R 35a )═C(R 35b )—*′, *—C(═S)—*′, *—C≡C—*′, a C 5 -C 30 carbocyclic group unsubstituted or substituted with at least one R 10a , or a C 1 -C 30 heterocyclic group unsubstituted or substituted with at least one R 10a ,

L 32 is a single bond, a double bond, *—N(R 36a )—*′, *—B(R 36a )—*′, *—P(R 36a )—*′, *—C(R 36a )(R 36b )—*′, *—Si(R 36a )(R 36b )—*′, *—Ge(R 36a )(R 36b )—*′, *—S—*′, *—Se—*′, *—O—*′, *—C(═O)—*′, *—S(═O)—*′, *—S(═O) 2 —*′, *—C(R 36a )═*′, *═C(R 36a )—*′, *—C(R 36a )═C(R 36b )—*′, *—C(═S)—*′, *—C≡C—*, a C 5 -C 30 carbocyclic group unsubstituted or substituted with at least one R 10a , or a C 1 -C 30 heterocyclic group unsubstituted or substituted with at least one Ria,

L 33 is a single bond, a double bond, *—N(R 37a )—*′, *—B(R 37a )—*′, *—P(R 37a )—*, *—C(R 37a )(R 37b )—*′, *—Si(R 37a )(R 37b )—*′, *—Ge(R 37a )(R 37b )—*′, *—S—*′, *—Se—*,*—O—*′, *—C(═O)—*′, *—S(═O)—*′, *—S(═O) 2 —*′, *—C(R 37a )═*′, *═C(R 37a )—*′, *—C(R 37a )═C(R 37b )—*′, *—C(═S)—*′, *—C≡C—*′, a C 5 -C 30 carbocyclic group unsubstituted or substituted with at least one R 10a , or a C 1 -C 30 heterocyclic group unsubstituted or substituted with at least one R 10a ,

L 34 is a single bond, a double bond, *—N(R 38a )—*′, *—B(R 38a )—*′, *—P(R 38a )*′, *—C(R 38a )(R 38b )—*′, *—Si(R 38a )(R 38b )—*′, *—Ge(R 38a )(R 38b )—*′, *—S—*′, *—Se—*,*—O—*′, *—C(═O)—*′, *—S(═O)—*′, *—S(═O) 2 —*′, *—C(R 38a )═*′, *═C(R 38a )—*′, *—C(R 38a )═C(R 38b )—*′, *—C(═S)—*′, *—C≡C—*, a C 5 -C 30 carbocyclic group unsubstituted or substituted with at least one R 10a , or a C 1 -C 30 heterocyclic group unsubstituted or substituted with at least one R 10a ,

n31 to n34 are each independently an integer from 0 to 5, wherein three or more of n31 to n34 are each independently an integer from 1 to 5,

when n31 is 0, L 31 is not present, when n32 is 0, L 32 is not present, when n33 is 0, L 33 is not present, and when n34 is 0, L 34 is not present,

when n31 is 2 or more, two or more of L 31 are identical to or different from each other, when n32 is 2 or more, two or more of L 32 are identical to or different from each other, when n33 is 2 or more, two or more of L 33 are identical to or different from each other, and when n34 is 2 or more, two or more of L 34 are identical to or different from each other,

R 31 to R 34 , R 35a , R 35b , R 36a , R 36b , R 37a , R 37b , R 38a , and R 38b are each independently hydrogen, deuterium, —F, —Cl, —Br, —I, —SF 5 , a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 3 -C 10 cycloalkyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkyl group, a substituted or unsubstituted C 3 -C 10 cycloalkenyl group, a substituted or unsubstituted C 2 -C 10 heterocycloalkenyl group, a substituted or unsubstituted C 6 -C 60 aryl group, a substituted or unsubstituted C 7 -C 60 arylalkyl group, a substituted or unsubstituted C 6 -C 60 aryloxy group, a substituted or unsubstituted C 6 -C 60 arylthio group, a substituted or unsubstituted C 1 -C 60 heteroaryl group, a substituted or unsubstituted C 2 -C 60 heteroarylalkyl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q 1 )(Q 2 )(Q 3 ), —Ge(Q 1 )(Q 2 )(Q 3 ), —N(Q 4 )(Q 5 ), —B(Q 6 )(Q 7 ), —P(═O)(Q 8 )(Q 9 ), or —P(Q 8 )(Q 9 ),

b31 to b34 are each independently an integer from 0 to 20,

two or more of R 31 in the number of b31 are optionally bonded to each other to form a C 5 -C 30 carbocyclic group unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group unsubstituted or substituted with at least one R 10a ,

two or more of R 32 in the number of b32 are optionally bonded to each other to form a C 5 -C 30 carbocyclic group unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group unsubstituted or substituted with at least one R 10a ,

two or more of R 33 in the number of b33 are optionally bonded to each other to form a C 5 -C 30 carbocyclic group unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group unsubstituted or substituted with at least one R 10a ,

two or more of R 34 in the number of b34 are optionally bonded to each other to form a C 5 -C 30 carbocyclic group unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group unsubstituted or substituted with at least one R 10a ,

two or more of R 31 to R 34 , R 35a , R 35b , R 36a , R 36b , R 37a , R 37b , R 38a , and R 38b are optionally bonded to each other to form a C 5 -C 30 carbocyclic group unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group unsubstituted or substituted with at least one R 10a , and

R 10a is defined as in connection with R 31 ,

M 51 (L 51 ) n51 (L 52 ) n52   Formula 5

wherein, in Formula 5,

M 51 is a transition metal,

L 51 is a ligand represented by Formula 5A,

L 52 is a ligand represented by Formula 5B,

n51 is 1, 2, or 3, and n52 is 0, 1, or 2,

Y 51 to Y 54 are each independently C or N,

CY 51 to CY 54 are each independently a C 5 -C 30 carbocyclic group or a C 1 -C 30 heterocyclic group,

R 51 to R 54 are each independently hydrogen, deuterium, —F, —Cl, —Br, —I, —SF 5 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 1 -C 60 alkylthio group, a substituted or unsubstituted C 3 -C 10 cycloalkyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkyl group, a substituted or unsubstituted C 3 -C 10 cycloalkenyl group, a substituted or unsubstituted C 2 -C 10 heterocycloalkenyl group, a substituted or unsubstituted C 6 -C 60 aryl group, a substituted or unsubstituted C 6 -C 60 aryloxy group, a substituted or unsubstituted C 6 -C 60 arylthio group, a substituted or unsubstituted C 1 -C 60 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q 1 )(Q 2 )(Q 3 ), —Ge(Q 1 )(Q 2 )(Q 3 ), —N(Q 4 )(Q 5 ), —B(Q 6 )(Q 7 ), —P(═O)(Q 8 )(Q 9 ), or —P(Q 8 )(Q 9 ),

b51 to b54 are each independently an integer from 1 to 20,

* and *′ each indicate a binding site to a neighboring atom,

at least one substituent of the substituted C 5 -C 30 carbocyclic group, the substituted C 1 -C 30 heterocyclic group, the substituted C 1 -C 60 alkyl group, the substituted C 2 -C 60 alkenyl group, the substituted C 2 -C 60 alkynyl group, the substituted C 1 -C 60 alkoxy group, the substituted C 3 -C 10 cycloalkyl group, the substituted C 1 -C 10 heterocycloalkyl group, the substituted C 3 -C 10 cycloalkenyl group, the substituted C 2 -C 10 heterocycloalkenyl group, the substituted C 6 -C 60 aryl group, the substituted C 6 -C 60 aryloxy group, the substituted C 6 -C 60 arylthio group, the substituted C 1 -C 60 heteroaryl group, the substituted C 1 -C 60 heteroaryloxy group, the substituted C 1 -C 60 heteroarylthio group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group is

deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, 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;

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 substituted with deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 2 -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 C 1 -C 60 heteroaryloxy group, a C 1 -C 60 heteroarylthio group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —Si(Q 11 )(Q 12 )(Q 13 ), —Ge(Q 11 )(Q 12 )(Q 13 ), —N(Q 14 )(Q 18 ), —B(Q 16 )(Q 17 ), —P(═O)(Q 18 )(Q 19 ), or any combination thereof;

a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 2 -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 C 1 -C 60 heteroaryloxy group, a C 1 -C 60 heteroarylthio group, a monovalent non-aromatic condensed polycyclic group, or a monovalent non-aromatic condensed heteropolycyclic group;

a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 2 -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, or a monovalent non-aromatic condensed heteropolycyclic group, each substituted with deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, 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 2 -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 C 1 -C 60 heteroaryloxy group, a C 1 -C 60 heteroarylthio group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —Si(Q 21 )(Q 22 )(Q 23 ), —Ge(Q 21 )(Q 22 )(Q 23 ), —N(Q 24 )(Q 25 ), —B(Q 26 )(Q 27 ), —P(═O)(Q 28 )(Q 29 ), or any combination thereof; or

—Si(Q 31 )(Q 32 )(Q 33 ), —Ge(Q 31 )(Q 32 )(Q 33 ), —N(Q 34 )(Q 35 ), —B(Q 36 )(Q 37 ), or —P(═O)(Q 38 )(Q 39 ), and

Q 1 to Q 9 , Q 11 to Q 19 , Q 21 to Q 29 , and Q 31 to Q 39 are each independently hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 3 -C 10 cycloalkyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkyl group, a substituted or unsubstituted C 3 -C 10 cycloalkenyl group, a substituted or unsubstituted C 2 -C 10 heterocycloalkenyl group, a substituted or unsubstituted C 6 -C 60 aryl group, a substituted or unsubstituted C 6 -C 60 aryloxy group, a substituted or unsubstituted C 6 -C 60 arylthio group, a substituted or unsubstituted C 1 -C 60 heteroaryl group, a substituted or unsubstituted C 1 -C 60 heteroaryloxy group, a substituted or unsubstituted C 1 -C 60 heteroarylthio group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, or a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group.

15 . The light-emitting device of claim 14 , wherein n34 is 0, and

X 31 is C, and a bond between X 31 and M 31 is a coordinate bond.

16 . The light-emitting device of claim 14 , wherein, in Formula 5, i) M 51 is Ir, and the sum of n51 and n52 is 3; or ii) M 51 is Pt, and the sum of n51 and n52 is 2.

17 . The light-emitting device of claim 13 , wherein the third compound is one of Compounds P1 to P52:

18 . The light-emitting device of claim 13 , wherein the fourth compound comprises a compound represented by Formula 4:

wherein, in Formula 4,

Z is B or N,

CY 41 to CY 43 are each independently a C 5 -C 30 carbocyclic group or a C 1 -C 30 heterocyclic group,

L 41 is *—N(R 44 )—*′, *—B(R 44 )—*′, *—P(R 44 )—*′, *—C(R 44 )(R 45 )—*′, *—Si(R 44 )(R 45 )—*′, *—Ge(R 44 )(R 45 )—*′, *—O—*′, *—S—*′, *—Se—*′, *—C(═O)—*′, or *—S(═O) 2 —*′,

L 42 is *—N(R 46 )—*′, *—B(R 46 )—*′, *—P(R 46 )—*′, *—C(R 46 )(R 47 )—*′, *—Si(R 46 )(R 47 )—*′, *—Ge(R 46 )(R 47 )—*′, *—O—*′, *—S—*′, *—Se—*′, *—C(═O)—*′, or *—S(═O) 2 —*′,

L 43 is *—N(R 48 )—*′, *—B(R 48 )—*′, *—P(R 48 )—*′, *—C(R 48 )(R 49 )—*′, *—Si(R 48 )(R 49 )—*′, *—Ge(R 48 )(R 49 )—*′, *—O—*′, *—S—*′, *—Se—*′, *—C(═O)—*′, or *—S(═O) 2 —*′,

n41 to n43 are each independently 0 or 1,

when n41 is 0, L 41 is not present, when n42 is 0, L 42 is not present, and when n43 is 0, L 43 is not present,

R 41 to R 49 are each independently hydrogen, deuterium, —F, —Cl, —Br, —1, —SF 5 , a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 3 -C 10 cycloalkyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkyl group, a substituted or unsubstituted C 3 -C 10 cycloalkenyl group, a substituted or unsubstituted C 2 -C 10 heterocycloalkenyl group, a substituted or unsubstituted C 6 -C 60 aryl group, a substituted or unsubstituted C 7 -C 60 arylalkyl group, a substituted or unsubstituted C 6 -C 60 aryloxy group, a substituted or unsubstituted C 6 -C 60 arylthio group, a substituted or unsubstituted C 1 -C 60 heteroaryl group, a substituted or unsubstituted C 2 -C 60 heteroarylalkyl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q 1 )(Q 2 )(Q 3 ), —Ge(Q 1 )(Q 2 )(Q 3 ), —N(Q 4 )(Q 5 ), —B(Q 6 )(Q 7 ), —P(═O)(Q 8 )(Q 9 ), or —P(Q 8 )(Q 9 ),

b41 to b43 are each independently an integer from 1 to 20,

two or more of R 41 in the number of b41 are optionally bonded to each other to form a C 5 -C 30 carbocyclic group unsubstituted or substituted with at least one R 10b or a C 1 -C 30 heterocyclic group unsubstituted or substituted with at least one R 10b ,

two or more of R 42 in the number of b42 are optionally bonded to each other to form a C 5 -C 30 carbocyclic group unsubstituted or substituted with at least one R 10b or a C 1 -C 30 heterocyclic group unsubstituted or substituted with at least one R 10b ,

two or more of R 43 in the number of b43 are optionally bonded to each other to form a C 5 -C 30 carbocyclic group unsubstituted or substituted with at least one R 10b or a C 1 -C 30 heterocyclic group unsubstituted or substituted with at least one R 10b ,

two or more of R 41 to R 49 are optionally bonded to each other to form a C 5 -C 30 carbocyclic group unsubstituted or substituted with at least one R 10b or a C 1 -C 30 heterocyclic group unsubstituted or substituted with at least one R 10b ,

R 10b is defined as in connection with R 41 ,

* and *′ each indicate a binding site to a neighboring atom,

at least one substituent of the substituted C 5 -C 30 carbocyclic group, the substituted C 1 -C 30 heterocyclic group, the substituted C 1 -C 60 alkyl group, the substituted C 2 -C 60 alkenyl group, the substituted C 2 -C 60 alkynyl group, the substituted C 1 -C 60 alkoxy group, the substituted C 3 -C 10 cycloalkyl group, the substituted C 1 -C 10 heterocycloalkyl group, the substituted C 3 -C 10 cycloalkenyl group, the substituted C 2 -C 10 heterocycloalkenyl group, the substituted C 6 -C 60 aryl group, the substituted C 6 -C 60 aryloxy group, the substituted C 6 -C 60 arylthio group, the substituted C 1 -C 60 heteroaryl group, the substituted C 1 -C 60 heteroaryloxy group, the substituted C 1 -C 60 heteroarylthio group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group is

deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, 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;

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 substituted with deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 2 -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 C 1 -C 60 heteroaryloxy group, a C 1 -C 60 heteroarylthio group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —Si(Q 11 )(Q 12 )(Q 13 ), —Ge(Q 11 )(Q 12 )(Q 13 ), —N(Q 14 )(Q 15 ), —B(Q 16 )(Q 17 ), —P(═O)(Q 18 )(Q 19 ), or any combination thereof;

a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 2 -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 C 1 -C 60 heteroaryloxy group, a C 1 -C 60 heteroarylthio group, a monovalent non-aromatic condensed polycyclic group, or a monovalent non-aromatic condensed heteropolycyclic group;

a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 2 -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, or a monovalent non-aromatic condensed heteropolycyclic group, each substituted with deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, 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 2 -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 C 1 -C 60 heteroaryloxy group, a C 1 -C 60 heteroarylthio group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —Si(Q 21 )(Q 22 )(Q 23 ), —Ge(Q 21 )(Q 22 )(Q 23 ), —N(Q 24 )(Q 25 ), —B(Q 26 )(Q 27 ), —P(═O)(Q 28 )(Q 29 ), or any combination thereof; or

—Si(Q 31 )(Q 32 )(Q 33 ), —Ge(Q 31 )(Q 32 )(Q 33 ), —N(Q 34 )(Q 35 ), —B(Q 36 )(Q 37 ), or —P(═O)(Q 37 )(Q 39 ), and

Q 1 to Q 9 , Q 11 to Q 19 , Q 21 to Q 29 , and Q 31 to Q 39 are each independently hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 3 -C 10 cycloalkyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkyl group, a substituted or unsubstituted C 3 -C 10 cycloalkenyl group, a substituted or unsubstituted C 2 -C 10 heterocycloalkenyl group, a substituted or unsubstituted C 6 -C 60 aryl group, a substituted or unsubstituted C 6 -C 60 aryloxy group, a substituted or unsubstituted C 6 -C 60 arylthio group, a substituted or unsubstituted C 1 -C 60 heteroaryl group, a substituted or unsubstituted C 1 -C 60 heteroaryloxy group, a substituted or unsubstituted C 1 -C 60 heteroarylthio group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, or a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group.

19 . The light-emitting device of claim 13 , wherein the fourth compound is one of Compounds D1 to D30:

20 . An electronic apparatus comprising the light-emitting device of claim 1 .