Effect of pH on Optic and Structural Characterization of Chemical Deposited AgI Thin Films

Abstract

AgI thin films were grown on amorphous commercial glass substrates with chemical bath deposition (CBD) at different pH values (2,3,4,5,6), 6 hours deposition time and 60 °C. The structure of the nanocrystals was characterized by X-ray diffraction (XRD). The ratio of Ag + and I -ions changed the crystalline structures. The presence of the Ag + ions produces the γ-phase of AgI and excess of iodine concentration produces β-phase of AgI. The pH: 4 was like a transition pH for these phases. The number of crystallites per unit area has maximum value at pH: 5, as the structure is re-crystallization to hexagonal phase. Also, the thicknesses of produced thin films were decreased with increased pH values. Therefore, transmission, reflection, extinction coefficients and refractive index of the materials were affected by thicknesses, and calculated to be 32, 35, 3, 11, 9 (%) -27, 25, 61, 45, 49 (%) -0.036, 0.032, 0.067, 0.107, 0.075 and 3.21, 3.02, 5.16, 8.35, 5.70 in 550 nm at pH: 2-3-4-5-6 values, respectively. The exciton peaks of AgI were observed at between 320 and 420 nm. Surface properties were investigated by using scanning electron microscopy (SEM).

Structural, Optical, and Chemical Characteristics of High‐Quality PbI2 Thin Films via Chemical Solution Deposition with Thermal Annealing

“…This technique does not require complex infrastructure, ergo it is low cost and easy to implement, and has been proven successful for the synthesis of numerous metal iodide thin films. [27][28][29][30] However, achieving good-quality films is complicated, because it requires fine tuning of the chemical formulation (reaction solution), as shown by the work of Kariper [3] where the structure and optical properties of the PbI 2 thin films are significantly influenced by the pH of the reaction solution.…”