Thiourea‐Derived Single‐Source Molecular Precursor For Spin‐Coated PbS Thin Films

In search of a suitable single‐source precursor for the deposition of nanostructured PbS thin films at moderate temperatures under ambient conditions, we have synthesized the ligand N‐(thiomorpholine‐4‐carbothioyl)benzamide and its corresponding lead(II) complex. The structures of both compounds were determined by single‐crystal X‐ray diffraction. In the complex, two ligands coordinate to a lead(II) atom in hemi‐directed geometry through S and O atoms. Secondary intermolecular Pb⋅⋅⋅S interactions group the complexes into pairs. As bulk powders, both the ligand and complex show nominal composition and purity as evidenced by elemental analysis, 1H NMR and IR spectroscopy. Thermal analysis of the lead(II) complex was carried out to understand its thermal decomposition behaviour for establishing a thin film fabrication protocol. Thin films of phase‐pure PbS were fabricated using this new molecular precursor at the comparatively low annealing temperature of 250 °C. The film showed nanoparticles with cuboidal morphology and a blue‐shifted optical absorption. PbS spin coating: The crystal structures of both N‐(thiomorpholine‐4‐carbothioyl)benzamide ligand and bis(N‐(thiomorpholine‐4‐carbothioyl)benzamidate)lead(II) complex are reported, and the usability of the complex as a single‐source molecular precursor for the deposition of PbS thin films via spin coating is demonstrated. The films show a blue shift in their absorption behavior and consist of particles with cuboidal morphology.