Organic–inorganic hybrid perovskites ABI3 (A = CH3NH3, NH2CHNH2; B = Sn, Pb) as potential thermoelectric materials: a density functional evaluation

Abstract

To assess the feasibility of the organic–inorganic perovskite iodides ABI₃ (A = CH₃NH₃, NH₂CHNH₂; B = Sn, Pb; X = I) for thermoelectric applications, we estimated their figures of merit (ZTs) as well as that of Bi₂Te₃, which is optimized for temperatures around 300 K, as a function of chemical potential on the basis of density functional theory calculations. Our analysis employed the tetragonal structures (P4mm) of (CH₃NH₃)PbI₃ and (CH₃NH₃)SnI₃, the trigonal (P3m1) structure of (NH₂CHNH₂)PbI₃, and the orthorhombic (Amm2) structure of (NH₂CHNH₂)SnI₃ to examine their thermoelectric properties around room temperature. Our work reveals that the ZTs of electron-doped ABI₃ perovskites can be as large as that of hole-doped Bi₂Te₃ whereas those of hole-doped ABI₃ are rather smaller so that, in thermoelectric performance, electron-doped perovskites ABI₃ can be as good as hole-doped Bi₂Te₃.