Stoichiometry, surface and structural characterization of lead iodide thin films

Abstract

In this work we present the structural properties and stoichiometry analysis of thin films of lead iodide (PbI 2 ). This material is a very promising semiconductor material for the development of X-ray detectors in digital medical imaging. An alternative deposition method called Spray Pyrolysis was used. We discuss the main advantages and limitations of the deposition process comparing three different starting material powders. Extra iodine atmosphere during deposition and the effect of post-deposition thermal treatment is also discussed. The structural properties were studied by X-ray diffraction, Atomic Force Microscopy (AFM), Scanning Electronic Microscopy (SEM) and stoichiometry analysis were performed using Energy Dispersive Spectroscopy (EDS).

Defect Engineering of BiI3 Single Crystals: Enhanced Electrical and Radiation Performance for Room Temperature Gamma-Ray Detection

“…The resulting DFEs are depicted in Figure . Bi-rich conditions, where the chemical potential of Bi reaches the maximum value (μ Bi = μ Bi,metal ), were considered given that iodine compounds are normally iodine deficient during growth due to the high vapor pressure of iodine and BiI 3 dissociation into Bi and I 2 at 250–300 °C. − The DFE of Sb Bi × is predicted to have the lowest energy, and thus, Sb will preferably reside in the Bi-site (Figure b). However, BiI 3 is normally under iodine deficient conditions that impose high concentrations of iodine vacancies in the system.…”

Effects of the PbBr2:PbI2 Molar Ratio on the Formation of Lead Halide Thin Films, and the Ratio’s Application for High Performance and Wide Bandgap Solar Cells

“…Each of these PbI 2 layers interacts weakly with adjacent layers, giving rise to different stacking patterns, and thus leading to various polytypes in single crystals. PbI 2 single crystals have commonly been fabricated by the Bridgeman-based technique, vapor growth, and the hot wall technique [1,9,11,[13][14][15][16][17][18], while polycrystalline thin films are formed by vacuum evaporation or the spin/spray coating of PbI 2 solutions [19][20][21][22][23][24]. Among these techniques, the deposition of PbI 2 polycrystalline layers from a solution is very simple, reliable, and economical.…”

Critical Role of Perovskite Film Stoichiometry in Determining Solar Cell Operational Stability: a Study on the Effects of Volatile A-Cation Additives

“…All the films show main diffraction peaks at 14.0°, 28.3°, and 31.7°, indicating the (001), (002), and (012) planes of cubic-phase perovskites. − The lattice constants of all these perovskite films are 6.32 Å, indicating that the added Cl after film annealing has little impact on perovskite crystal structure. The stoichiometric 10 min film and the 3.17% excess PbCl 2 film both show diffraction peaks at 12.7°, which is classified as the (001) peak in cubic-phase PbI 2 . − The PbI 2 peak intensity in the stoichiometric 10 min film is less than that of the 3.17% excess PbCl 2 10 min film, just as the flake amount in the stoichiometric 10 min film is less than that in the 3.17% excess PbCl 2 film. In the meantime, the PbBr 2 and PbCl 2 characteristic XRD peaks are not observed .…”

“…[25][26][27][28] The stoichiometric 10 min film and the 3.17% excess PbCl2 film both show diffraction peaks at 12.7°, which is classified as the (001) peak in cubic phase PbI2. [29][30][31] The PbI2 peak intensity in the stoichiometric 10 min film is less than that of the 3.17% excess PbCl2 10 min film, just as the flake amount in the stoichiometric 10 min film is less than that in the 3.17% excess PbCl2 film. In the meantime, the PbBr2 and PbCl2 characteristic XRD peaks are not observed.…”