  Cyclometalled Ir(III) compounds are the preferred choice as organic emitters
in Organic Light Emitting Diodes. In practice, the presence of the transition
metals surrounded by carefully designed ligands allows the fine tuning of the
emission frequency as well as a good efficiency of the device. To support the
development of new compounds the experimental measurements are generally
compared with ab-initio calculation of the absorption and emission spectra. The
standard approach for these calculations is TDDFT with hybrid exchange and
correlation functional like the B3LYP. Due to the size of these compounds the
application of more complex quantum chemistry approaches can be challenging. In
this work we used Many Body Perturbation Theory approaches (in particular the
GW approximation with the Bethe-Salpeter equation) implemented in gaussian
basis sets, to calculate the quasiparticle properties and the adsorption
spectra of six cyclometalled Ir(III) complexes going behind TDDFT. In the
presented results we compared standard TDDFT simulation with BSE calculations
performed on top on perturbative G 0 W 0 and accounting for eigenvalue self
consistency. Moreover, in order to investigate in detail the effect of the DFT
starting point, we concentrate on Ir(ppy) 3 performing GW-BSE simulations
starting from different DFT exchange and correlation potentials.
