Lead-sulfur interaction induced damp and water stability in pure formamidinium lead triiodide

Muhammed P U Haris; Eliseo Ruiz; Samrana Kazim; Shahzada Ahmad

doi:10.1016/j.xcrp.2023.101516

Lead-sulfur interaction induced damp and water stability in pure formamidinium lead triiodide

Cell Rep Phys Sci. 2023 Aug 16;4(8):101516. doi: 10.1016/j.xcrp.2023.101516.

Authors

Muhammed P U Haris¹, Eliseo Ruiz², Samrana Kazim^{1

3}, Shahzada Ahmad^{1

3}

Affiliations

¹ BCMaterials, Basque Center for Materials, Applications, and Nanostructures, UPV/EHU Science Park, 48940 Leioa, Spain.
² Departament de Química Inorgànica i Orgànica, Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, 08028 Barcelona, Spain.
³ IKERBASQUE, Basque Foundation for Science, 48009 Bilbao, Spain.

Abstract

Research efforts in various multitudes have been demonstrated to stabilize methylammonium (MA)- and bromide (Br)-free formamidinium lead triiodide (FAPI) perovskite thin films. Despite these commendable efforts, pure FAPI perovskite thin film is prone to critical phase-transition issues due to its thermodynamically stable non-perovskite phase (2H). Here, in this work, we propose a rational additivization strategy to overcome this challenge. Our multifunctional ammonium salt containing a sulfur heteroatom shifts the thermodynamic stability from the 2H phase to an intermediate phase closer to the cubic phase. Along with the high crystallinity, micron-sized grains with preferred (00h) facet orientation stem the Pb^…S interaction to offer exceptional stability against high relative humidity, direct water incursion, and shelf-life aging. Our findings through experimental and theoretical studies substantiate the role of Pb^…S interaction in stabilizing the perovskite cubic phase and the stoichiometric distribution of elemental components.

Keywords: lead-sulfur interaction; micron-sized grains; multifunctional additivization; water-stable FAPbI3.