The cathode 150, is an electrode that is particularly efficient for injecting electrons or negative charge carriers. The cathode can be any metal or nonmetal having a lower work function than the anode. Materials for the cathode can be selected from alkali metals of Group 1 (e.g., Li, Cs...
FIG. 1 shows Formula II for phenylpyridine and phenylpyrimidine ligands useful in the metal complex of the invention, and Formula II-H for the ligand precursor compound. FIG. 2 shows Formula III for phosphinoalkanoxide ligands useful in the metal complex of the invention, and Formula III-H fo...