Cs 2 InAgCl 6 : A New Lead-Free Halide Double Perovskite with Direct Band Gap

A2BB′X6 halide double perovskites based on bismuth and silver have recently been proposed as potential environmentally friendly alternatives to lead-based hybrid halide perovskites. In particular, Cs2BiAgX6 (X = Cl, Br) have been synthesized and found to exhibit band gaps in the visible range. However, the band gaps of these compounds are indirect, which is not ideal for applications in thin film photovoltaics. Here, we propose a new class of halide double perovskites, where the B3+ and B+ cations are In3+ and Ag+, respectively. Our first-principles calculations indicate that the hypothetical compounds Cs2InAgX6 (X = Cl, Br, I) should exhibit direct band gaps between the visible (I) and the ultraviolet (Cl).…

• LT
  Leverhulme Trust

  Award: RL-2012-001
• EA
  Engineering and Physical Sciences Research Council

  Awards: EP/L024667/1, EP/J009857/1, EP/M020517/1, EP/M020517/1, EP/J009857/1, EP/L024667/1
• H2
  Horizon 2020

  Award: 696656