Synthesis and Optical Properties of Rb-Doped Halide Double Perovskite Cs₂AgBiBr₆

Although lead-based halide perovskite compounds experienced a surge of interest due to achieving high photovoltaic efficiencies near the theoretical limit there has been a shift to exploring alternative materials as a result of thermal stability and toxicity issues[1]. Double perovskites have been proposed as functional alternatives which mimics band characteristics of these materials due to having a similar octahedral orbital structure[2] . Samples of Rb-doped Cs₂AgBiBr₆ have been synthesized using a controlled cooling method[3] where Rb has been doped on the Cs and Ag sites simultaneously and characterized using X-ray powder diffraction and energy-dispersive X-ray spectroscopy. The optical properties of these synthesized crystals will be investigated and compared to those of undoped Cs₂AgBiBr₆ via UV-Vis transmission measurements to characterize the optical bandgap and temperature and polarization dependent Raman scattering to study the vibrational modes.

[1] Y. Zhou et al. Energy & Environmental Science. 12(5), 1495–1511, 2019.

[2] T. Umebayashi et al. Physical Review. B. 67(15), 155405, 2003.

[3] L. Yin et al. Advanced Optical Materials. 7 (19) 1900491, 2019.