Application of Experimentally Determined Acoustic Impedance Ratio for Homogeneous Co-Evaporation of Perovskite Absorbers

We present the co-evaporation of metal halide perovskite absorbers on wafer scale. We determine the acoustic impedance ratio Z and density ρ of methyl ammonium iodide and lead iodide. We use them for the deposition of perovskite absorbers on 6-inch-diameter silicon wafers. We evaluate the structural and optical conformity of the deposition with x-ray diffraction and spectral photoluminescence. We use a camera-based fluorescence detection system to prove the homogeneity of the luminescence intensity. With our evaporation parameters, we achieve a conformal absorber deposition of controllable thickness and stoichiometry. The lead iodide precursor fully transforms into perovskite during the deposition without any post-deposition annealing. The as-deposited layers show a homogeneous photoluminescence signal at 1.61 eV at room temperature.