Photophysical and electroluminescence properties of bis(2′,6′-difluoro-2,3′-bipyridinato-N,C4′)iridium(picolinate) complexes: effect of electron-withdrawing and electron-donating group substituents at the 4′ position of the pyridyl moiety of the cyclometalated ligand

Electronic effects on the photophysics of Ir³⁺ compounds.