  Single crystals of Cs2BiAgBr6 lead-free perovskite were grown by
crystallization from supersaturated solution. According to characterization by
XRD and EBSD methods the double perovskite single crystal are of the cubic
Fm-3m symmetry with the lattice constant a = 11.20 {\AA}. DFT predictions based
on the single crystal X-ray diffraction analysis reveal that the material is an
indirect band gap semiconductor. Low temperature (1.4 K) photoluminescence
spectra demonstrate three broadened bands that correspond to two lowest
computed indirect and one direct band-to-band transitions.
