Cesium lead iodide (CsPbI₃) has long been a promising light absorbing material for perovskite solar cells. Researchers from the Navrotsky lab, in a recently published study (J. Am. Chem. Soc. 2019, 141, 14501) conducted calorimetric studies on cubic(α) and orthorhombic(δ) CsPbI₃ polymorphs, obtaining their enthalpies of formation from binary iodides, and discussing the relative stabilities. Cubic phase CsPbI₃, the desirable phase for light absorbing material, is confirmed to be metastable under ambient conditions.
More information at https://pubs.acs.org/doi/10.1021/jacs.9b05924