Unveilling the Growth Mechanism of 2D, Quasi- 2D, Quasi-3D and 3D Halide Perovskite Thin Films

Fabrication of high performance organo-metal halide perovskite films for various applications remains a challenge. Here we show the behavior of solvents and perovskite elements for 2D (n=1), Quasi-2D (n=3), Quasi-3D (n=9) Ruddlesden-Popper and 3D (n=infinity), which are the most used perovskite structures and compositions. Using the real-time depth detection by glow discharge optical emission spectroscopy (GD-OES) developed by our research group, we have assessed the growth direction of the films based on the depth distribution of the solvent in the film at different annealing times. On this basis, we show for the first time the growth direction of 2D (Lateral Growth), Quasi-2D (Downward Growth) and Quasi-3D (Lateral Growth) perovskite films. By revealing the film growth mechanism, an optimization of its direction is revealed which aims at producing, in the future, perovskite films for high performance opto-electronic devices.