TADF emitters based on a tri-spiral acridine donor and a spiro-B-heterotriangulene acceptor with high horizontal dipole orientation ratios and high efficiencies in deep-blue OLEDs

Linearly expanded rigid TADF emitters, composed of a tri-spiral acridine donor and a spiro-fluorenyl- B -heterotriangulene acceptor, exhibit very high horizontal dipole orientation ratios, thereby achieving high efficiencies in deep-blue OLEDs.