Ultrafast excited state relaxation dynamics in heteroleptic Ir(III) complex, fac-Ir(ppy)2(ppz), revealed by femtosecond x-ray transient absorption spectroscopy Jungkweon Choi, Mina Ahn, Jae Hyuk Lee, Doo-Sik Ahn, Hosung Ki, Inhwan Oh, Chi Woo Ahn, Eun Hyuk Choi, Yunbeom Lee, Seonggon Lee, Jungmin Kim, Dae Won Cho, Kyung-Ryang Wee and Hyotcherl Ihee Abstract A typical metal complex has a central metal surrounded by multiple ligands, which greatly affect the properties of the whole complex.