A series of pure orange-yellow iridium complexes with low efficiency roll-off: A computational study

Abstract

The electronic structures and spectroscopic properties of heteroleptic cyclometalated iridium(III) complexes were investigated. The geometries, electronic structures, and the lowest-lying excited states of (DBQ)₂Ir(acac) and (MDQ)₂Ir(acac) were investigated via density functional theory-based approaches. A series of designed models of (DBQ)₂Ir(dpis), (DBQ)₂Ir(tpip), (MDQ)₂Ir(dpis) and (MDQ)₂Ir(tpip) was also calculated for comparison. The structures in the ground and excited states were optimized via B3LYP method. The lowest absorptions and emissions spectra were evaluated via TD-B3LYP and TD-PBE1PBE methods. The computational results reveal that the emission peaks of the designed complexes are at around 585―640 nm, which belong to the orange-yellow wavelength. The frontier molecular orbital properties indicate that the Ir(III) complexes have low efficiency roll-off.

Keywords

Organic light-emitting diode(OLED) / Ir(III) complex / Time-dependent density functional theory(TD-DFT) / Excited state / Efficiency roll-off

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