Two new isostructural double perovskites, Cs2AgSbCl6 and Cs2AgInCl6, have been synthesized and characterized. Cs2AgSbCl6 has an indirect band gap of 2.16 eV, while Cs2AgInCl6 possesses a direct bandgap of 3.29 eV. Cs2AgSbxIn1-xCl6 (x = 0.5, 0.4 and 0.2) solid solutions exhibit the transition from indirect to direct bandgaps at x = 0.4. Electronic structure calculations reveal that the transition from indirect to direct bandgaps is driven by an inversion of the unoccupied s- and p-states of Sb and In. These results open up an avenue for tuning the optical indirect to direct bandgaps in double perovskites based on less toxic elements and more air/moisture stable than hybrid lead halide perovskites. In addition, photoconductivity properties, temperature and wavelength dependence of structural and electronic properties have been performed and will be discussed.

Tuning indirect to direct bandgaps in double perovskites

253rd National Meeting (2017)

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