Theoretical Design Study on the Electronic Structures and Phosphorescent Properties of Four Iridium(III) Complexes

Abstract

<div><p>The geometry structures, electronic structures, absorption, and phosphorescent properties of four Ir(III) complexes have been investigated using the density functional method. Calculations of ionization potential (IP) and electron affinity (EA) were used to evaluate the injection abilities of holes and electrons into these complexes. The result also indicates that the –CF₃ substituent group on the ligand not only change the character of transition but affect the rate and balance of charge transfer. The lowest energy absorption wavelengths are located at 428 nm for <b>1a</b>, 446 nm for <b>1b</b>, 385 nm for <b>2a</b>, and 399 nm for <b>2b</b>, respectively, in good agreement with the energy gap (Δ<i>E</i>_L-H) trend because the HOMO–LUMO transition configurations are predominantly responsible for the <i>S</i>₀→<i>S</i>₁ transition. <b>2b</b> has the 433 nm blue emission, which might be a potential candidate for blue emitters in phosphorescent dopant emitters in organic light emitting diodes (OLEDs). The study could provide constructive information for designing novel OLEDs materials in the future.</p><p><i>[Supplemental materials are available for this article. Go to the publisher's online edition of Molecular Crystals and Liquid Crystals to view the free supplemental file.]</i></p></div