Pure Iodide Multication Wide Bandgap Perovskites by Vacuum Deposition

Abstract

The CsPbI 3 perovskite has a suitable bandgap (≈1.7 eV) for application in tandem solar cells. One challenge for this compound is that the semiconducting perovskite phase is not stable at room temperature, when it tends to form a yellow nonperovskite phase with a bandgap of approximately 2.8 eV. Therefore, many reports have been focused on the stabilization of the CsPbI 3 black perovskite phase through the use of additives during solution processing. Vacuum deposited CsPbI 3 has been seldom reported, as in this case, the insertion of stabilizing agents is more challenging. In this work, we demonstrate the vacuum processing of CsPbI 3 perovskite films at room temperature, obtained by incorporating dimethylammonium iodide by cosublimation with CsI and PbI 2 . As-prepared films were applied in planar solar cells, leading to an average power conversion efficiency (PCE) exceeding 12%. In order to improve the device performance, we introduced a third A-site cation (methylammonium) in a four-source deposition process. This pure iodide formulation can be used in wide bandgap solar cells with a PCE up to 14.8%.

High-entropy alloy screening for halide perovskites

“…, CsPbI 3 's metastable polymorphs). 1,2 There are more reports of single-phase inorganic HEAHP (Table S4, ESI†) 71–219 and hybrid organic–inorganic HEAHP (Table S5, ESI†), 220–285 but more investigation into single-phase boundaries is needed to confirm the broadscale applicability of UCV for screening HEAHP.…”