Thermoelectric Properties of Halide Perovskite Thin Films

One-step solution processed Cesium Tin halide perovskites (CsSnI
3
) known as lead-free halide perovskite were explored for thermoelectric applications. We report thermoelectric properties of CsSnI
3
with some dopants, such as In, Sb, Ni, Mg and Cu in different concentrations (50, 100 ppm) to control the carrier concentration. The fabricated thin film shows p-type characteristics and their power factors were around 100μW/(m
²
· K) with any dopants in different concentrations. Their properties agreed with ab-initio calculation for CsSnI
3
under the constant relaxation time assumption (τ=2×10
^-14
s). The high electrical conductivity is realized by Sn
⁴⁺
increase (Sn
²⁺
oxidation) was confirmed by XPS measurements. Thermal conductivity was also measured to be around 0.3 W/(m· K) by differential 3ω method. The printable materials will will help for further development of direct thermal energy harvesting devices near room temperature.