Light-emitting material with a polycyclic ligand

A metal complex, comprising a ligand La having a structure represented by Formula 1:

• wherein the ring A and the ring B are each independently selected from a five-membered unsaturated carbocyclic ring, an aromatic ring having 6 to 30 carbon atoms, or a heteroaromatic ring having 3 to 30 carbon atoms;
• Ri represents, at each occurrence identically or differently, mono-substitution, multiple substitutions or non-substitution;
• and Rii represents, at each occurrence identically, or differently, mono-substitution, multiple substitutions or non-substitution;
• Y is selected from SiRyRy, GeRyRy, O, S or Se;
• when two Ry are present at the same time, the two Ry may be the same or different;
• X1 and X2 are, at each occurrence identically or differently, selected from CRx or N;
• R, Ri, Rii, Rx and Ry 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;
• adjacent substituents Ri, Rx, Ry, R, and Rii can be optionally joined to form a ring;
• the metal is selected from a metal with a relative atomic mass greater than 40.