On the Deposition of Lead Halide Perovskite Precursors by Physical Vapor Method

In this work, homogeneous and compact thin film deposition using physical vapor methodology is described for a series of inorganic perovskite precursors: lead chloride (PbCl2), lead bromide (PbBr2), and lead iodide (PbI2). The thermal characterization and volatility of all these compounds were obtained: due to enthalpic and entropic contributions, the volatility, crucial for understanding the phase equilibria and thin film growth, of the solid and liquid phases of lead halides increases with the size of the halogen. The morphological analysis by scanning electron microscopy (SEM) reveals that the deposited thin films have high surface coverage and uniformity. Additionally, X-ray diffraction (XRD) evidenced the crystallinity of the prepared films on different surfaces. According to UV-vis spectroscopy, thin films of PbI2 exhibit good optical properties with a band gap energy of 2.3 eV.