Superlattices of Semiconductor Quantum-Size Lead Sulfide Particles Prepared by Topotactic Gas-Solid Reaction

Superlattices of quantum particles can be prepared by topotactic gas–solid reaction, as demonstrated here. The preparation of disk-like lead sulfide nanoparticles arranged within organic crystals of n-alkanoic acids or thin films of ω-hydroxyalkoxy phenyl propionic acids by reaction of the corresponding lead salts with gaseous H2S is described. The progress of the reaction is monitored by Fourier transform infrared spectroscopy and X-ray powder diffraction. Three processes are identified as being involved in the transformation: reaction, diffusion, and nucleation.