Ag/In lead‐free double perovskites
Fang Liu, Daniela Marongiu, Riccardo Pau, Valerio Sarritzu, Qingqian Wang, Stefano Lai, Alessandra Geddo Lehmann, Francesco Quochi, Michele Saba, Andrea Mura, Giovanni Bongiovanni, Alessandro Mattoni, Claudia Caddeo, Andrea Bosin, Alessio Filippetti
Abstract
Abstract Lead‐free Cs 2 AgInCl 6 and Cs 2 AgInBr 6 double perovskites are studied by a combination of advanced ab‐initio calculations and photoluminescence experiments. We show that they are insulators with direct band gaps of 2.53 and 1.17 eV, respectively; most importantly, they are characterized by unusually low absorption rates in a ~1 eV wide energy region above the band gap, caused by rather peculiar electronic properties. Consequently, this low absorption conveys very long recombination lifetimes, up to milliseconds at low temperature. Our theoretical analysis suggests that such materials can achieve a good compromise between photoconversion efficiency (above 10%) and visible transmittance (above 30%), which makes them potentially suited for lead‐free semitransparent solar cell applications. image