A metal complex, having a general formula of M(La)m(Lb)n(Lc)q, wherein La, Lb, and Lc are the first ligand, the second ligand and the third ligand coordinated to the metal M, respectively;
- wherein Lc is a monoanionic bidentate ligand, and Lc is the same as or different from the La or the Lb;
- wherein La, Lb, and Lc can be optionally joined to form a tetradentate ligand;
- wherein the metal M is selected from a metal with a relative atomic mass greater than 40;
- wherein m is 1 or 2, n is 1 or 2, q is 0 or 1, and m+n+q equals to the oxidation state of the metal M;
- when m is 2, two La can be the same or different;
- when n is 2, two Lb can be the same or different;
- wherein the ligand La has, at each occurrence identically or differently, a structure represented by Formula IA, and the ligand Lb has, at each occurrence identically or differently, a structure represented by Formula IB:
- wherein
- in Formula IA, W1, W2, W3, and W4 are each independently selected from N or CRw;
- X1, X2, X3, and X4 are each independently selected from N, C, or CRx;
- V1, V2, V3, and V4 are each independently selected from N or CRy;
- in Formula IB, Y1, Y2, Y3, and Y4 are each independently selected from N or CRy;
- Z1, Z2, Z3, and Z4 are each independently selected from N, C, or CRz;
- U1, U2, U3, and U4 are each independently selected from N or CRu;
- wherein Q is, at each occurrence identically or differently, selected from O, S, or Se;
- wherein Rw, Ry, Ru, Rv, Rx, Rz, and R are, at each occurrence identically or differently, selected from the group consisting of:
- hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 ring carbon atoms, substituted or unsubstituted heteroalkyl having 1 to 20 carbon atoms, substituted or unsubstituted arylalkyl having 7 to 30 carbon atoms, substituted or unsubstituted alkoxy having 1 to 20 carbon atoms, substituted or unsubstituted aryloxy having 6 to 30 carbon atoms, substituted or unsubstituted alkenyl having 2 to 20 carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 30 carbon atoms, substituted or unsubstituted alkylsilyl having 3 to 20 carbon atoms, substituted or unsubstituted arylsilyl having 6 to 20 carbon atoms, substituted or unsubstituted amino having 0 to 20 carbon atoms, an acyl group, a carbonyl group, a carboxylic acid group, an ester group, a cyano group, an isocyano group, a sulfanyl group, a sulfinyl group, a sulfonyl group, a phosphino group, and combinations thereof;
- wherein adjacent substituents Rw, Rv, Rx, and R can be optionally joined to form a ring;
- wherein adjacent substituents Ry, Ru, and Rz can be optionally joined to form a ring.