The present disclosure is related to organic acceptor-donor-acceptor compounds as non-fullerene acceptors for use in organic photovoltaics.

A transition metal complex is provided, which has a formula selected from: [M(A)(B)(C)].sup.abY, [M(A)(D)(E)(F)].sup.abY, or [M(A)(G)(H)(O)(P)].sup.abY; wherein: M is a transition metal element; A is a bidentate ligand containing a benzene ring and a carbene heterocyclic ring with at least one nitrogen atom; B, C, and D are each independently a bidentate ligand selected from the group consisting of a structure represented by Formula (1) and a structure represented by Formula (2), as shown below; E, F, G, H, O, and P are each independently a monodentate ligand selected from a heterocyclic ring containing at least one heteroatom, CN.sup., or Cl.sup.;

##STR00001##

##STR00002##

in Formula (1), R.sup.1 and R.sup.2 are each independently selected from a hydrogen atom, an alkyl group, an alkoxy group, or an alkylamino group; in Formula (2), R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are each independently selected from an alkyl group, a substituted or an unsubstituted aryl group.