ExplorinG by in situ and operando techniques the native dEgradation MechanIsms and longe range propagatioN In metal halide perovskite

GEMINI aims to advance fundamental understanding about the halide perovskite structure dynamic subsequently to photons absorption and how the latter can seed the early stage degradation. The state-of-the-art overflows of comparative ex situ analysis before and after ageing. This approach does reveal neither information on early stage degradation nor relevant information on their propagation. GEMINI has the ambition to fill in this understanding gap through a holistic approach to cover the multiscale degradation facets. For this, specific developments are integrated, in particular a table-top time-resolved X-ray scattering diffractometer to explore ultrafast structural dynamic in lab. GEMINI addresses all drawbacks of ex situ analysis and the constrains of the perovskite sensitiveness to high probe dose or high vacuum which itself contribute to the degradation. GEMINI will reveal live information resulting exclusively from in situ and operando approaches based on low-dose techniques, through specifically developed sample chambers and setup modifications. Ultrafast time-resolved and electron spin resonance spectroscopies, time-resolved and steady-state X-ray diffraction and live-scanning environmental transmission electron microscopy (STEM) combined to the latest development in 4D-STEM/ASTAR are combined to gather comprehensive multiscale information about degradation upon all relevant ISOS stressors, one at once and in combination to assess the synergetic effects. GEMINI is built upon solid background competences with these advanced techniques to ensure impacts beyond the state-of-the art (SoA): (i) understanding perovskite structural dynamic and relaxation upon photo-excitation down to 1ps time scale, (ii) revealing the multiscale degradation pathways from seeds to long-range depending on ISOS stressors, (iii) networking with EU funded projects in the field to go beyond SoA materials analysis and implement predictive model for ageing.