Preparation and Structure of Q-State Lead Sulfide Monolayers in Metastable Stearic Acid Langmuir-Blodgett Films

Article abstract of DOI:10.1021/j100186a072

Monolayers of Q-state PbS were prepared by exposure of Langmuir-Blodgett (LB) films of lead stearate to H2S at a pressure of 1 Torr.Its long spacing measured by X-ray diffraction is 50.5 +/- 0.2 Angstroem which is just the same with that of lead stearate LB films.It was determined by X-ray diffraction and IR that the hydrocarbon chains are still packed in an orthorhombic unit cell after the reaction.The carboxylic groups yielded by the reaction form a ring structure by hydrogen bonds which controls PbS within a monolayer.A structured UV-visible absorption spectrum of the PbS monolayer was obtained.The PbS monolayer consists of a two-dimensional domain or linear form of PbS.The latter is more possible.Their size is almost homogeneous.The onset of the absorption of PbS monolayer is blue-shifted by 1.4 eV with respect to bulk PbS.