In this work, high-quality PbS thin films were prepared by the chemical bath deposition (CBD) method for different molarities of sulfur precursors (1 M to 1.4 M) in a basic solution. The composition, morphology, and structural and optical properties of the PbS thin films were studied by means of scanning electron microscopy (SEM–EDS), X-ray diffraction (XRD), and UV–visible spectrophotometry (UV–Vis). The spectra obtained by XRD show that the PbS thin films crystallize in a NaCl structure with the grating parameter (a = 5.9202 Å) and the (002) plane is a preferential orientation of the films. The optical band gap decreases from 1.5 to 1.23 eV as the grain size of the PbS thin films increases from 15 to 37 nm. The decrease in the band gap is due to quantum confinement effects promoted by the small Bohr radius of this material (18 nm). Our experimental results have been validated by theoretical calculations in the framework of the functional density theory (FDT) using the full potential linearized augmented plane wave (FP-LAPW) as implemented in the WIEN2K code. The value of the optical band gap found in PbS nanoparticles is suitable for solar cell applications.

在这项工作中，通过化学浴沉积 (CBD) 方法在碱性溶液中制备了不同摩尔浓度的硫前体 (1 M 至 1.4 M) 的高质量 PbS 薄膜。通过扫描电子显微镜 (SEM-EDS)、X 射线衍射 (XRD) 和紫外-可见分光光度法 (UV-Vis) 研究了 PbS 薄膜的组成、形貌、结构和光学性质。通过 XRD 获得的光谱表明 PbS 薄膜在具有光栅参数的 NaCl 结构中结晶 ( a = 5.9202 Å) 并且 (002) 平面是薄膜的优先取向。随着 PbS 薄膜的晶粒尺寸从 15 nm 增加到 37 nm，光学带隙从 1.5 eV 减小到 1.23 eV。带隙的减小是由于这种材料的小玻尔半径 (18 nm) 促进了量子限制效应。我们的实验结果已通过功能密度理论 (FDT) 框架中的理论计算得到验证，使用全势线性增强平面波 (FP-LAPW)，如在 WIEN2K 代码中实施。在 PbS 纳米粒子中发现的光学带隙值适用于太阳能电池应用。