Pressure-modulated electronic and optical properties, and high thermoelectric performance of a new lead-free double perovskite Rb2KBiCl6.

It has become a priority of physics, chemistry, and material science to find new perovskite materials with environmentally friendly, excellent photoelectric properties and stable structures. This paper reports the design of lead-free double perovskite Rb2KBiCl6 and the effects of pressure on its structural, electronic, and optical properties. Also, its thermoelectric (TE) properties were systematically studied using a first-principles calculation based on density functional theory (DFT). It is found that Rb2KBiCl6 exhibits significant optical absorption in the ultraviolet range and that the band gap is an ideal choice for series photovoltaic applications and for use in wide-band-gap photovoltaic materials. At the same time, Rb2KBiCl6 shows excellent TE properties. In addition, the research results suggest a new way to adjust the crystal structure, optical band gap, and electronic structure of such materials. [ABSTRACT FROM AUTHOR]