Proceedings of International Conference on Perovskite and Organic Photovoltaics and Optoelectronics (IPEROP19)
Publication date: 23rd October 2018
Organic-inorganic halide perovskites have received significant attention because of their high photoelectric conversion efficiency and printable preparation. Among the fundamental physical properties of this type of material, its thermal properties are especially interesting because solar cell devices are affected by solar radiative heat and they have shown promise as thermoelectric materials. Therefore, to understand their thermal properties, we investigated the lattice dynamics of organic-inorganic halide perovskites by first-principles calculations.
The lattice thermal conductivity of Pb-free cubic CH3NH3SnI3 was calculated using lattice dynamics calculation with first-principles. The calculated lattice thermal conductivity of the cubic CH3NH3SnI3 was very low compared to those of other inorganic materials, possibly derived from low-energy acoustic phonon modes. Our results are consistent with those previously published regarding CH3NH3PbI3 [1]. However, imaginary frequency (soft) modes were observed, resulting in instability of the cubic structure. Consideration of lattice instability is required to accurately estimate thermal properties using lattice dynamics calculations.