Nanoparticles of lead sulfide in porous glasses prepared by the sol-gel method

PbS semiconductor nanoparticles were grown inside the matrices of zirconium oxide (ZrO₂) and zirconium-silica-polyurethane (ZSUR) prepared by the sol-gel method. Zirconium ormosil included polyurethane used to control the growth and aggregation of PbS nanoparticles. The new matrix allows the incorporation of up to 40% PbS forming a characteristic structure of dendrite by reacting lead acetate with ammonium thiocyanate in the sol-gel matrix. The sol precursors of the matrix for ZSUR contain ZrO₂ matrix solution, epoxy-silica-ormosil (ESOR) and diurethane siloxane (DURS) synthesized separately. The size of nanoparticles as determined by transmission electron microscopy (TEM) ranges between 2-4 nm for 20% PbS in zirconium oxide and 8-10 nm for 20% PbS in ZSUR matrices. The porosity of the glasses is determined using the nitrogen adsorption technique. The pore size for ZSUR doped with 2% of PbS as determined by BET is 1.54 nm. Quantum size effect was observed from the shifts of absorption and photoluminescence (PL).