Paz Sebastia-Luna1,Unnati Pokharel2,Bas Huisman1,Lambert Jan Anton Koster2,Francisco Palazon1,3,Henk Bolink1
University of Valencia1,University of Groningen2,Universidad Politécnica de Cartagena3
Paz Sebastia-Luna1,Unnati Pokharel2,Bas Huisman1,Lambert Jan Anton Koster2,Francisco Palazon1,3,Henk Bolink1
University of Valencia1,University of Groningen2,Universidad Politécnica de Cartagena3
Thermoelectric generators (TEGs) represent a very promising source of renewable energy, as they directly convert (waste) heat into electricity. Most current thermoelectric materials have important drawbacks, such as toxicity, scarceness, and peak operating temperatures above 300 <sup>0</sup>C. Herein, we report the thermoelectric properties of different crystalline phases of Sn-based perovskite thin films. A novel 2D phase, Cs<sub>2</sub>SnI<sub>4</sub>, is obtained through vacuum thermal deposition and easily converted into the black β phase of CsSnI<sub>3</sub> (B-β CsSnI<sub>3</sub>) by annealing. B-β CsSnI<sub>3</sub> is a <i>p</i>-type semiconductor with a figure-of-merit (ZT) ranging from 0.021 to 0.033 for temperatures below 100 <sup>0</sup>C, which makes it a promising candidate for applications such as the Internet of Things (IoT). The B-β phase is stable under an inert atmosphere but spontaneously oxidizes to Cs<sub>2</sub>SnI<sub>6</sub> when exposed to air. In-detail thermoelectric study for both compounds is presented, showing potential for implementation in low temperature operating TEGs.