Experimental X-ray diffraction patterns of unannealed and annealed Cu2AgBiI6films (in air) using Cu-Ka as the radiation source. Unannealed, 110, 130, and 150 C annealed films all refine to a single rhombohedral Cu2AgBiI6phase (spacegroupRm), but with varying impurity constitutions. Impurity peaks belonging to BiI3, CuI, and metallic bismuth are marked with (#), (*), and (**), respectively. Reflections from the quartz substrate are marked with (+).
