Room temperature photoluminescence of PbS quantum dots: Capping agent and thermal effect

The most efficient method for obtaining high concentration, monodispersed quantum dots is the sol gel method. This manuscript reports room temperature photoluminescence (PL) of lead sulfide (PbS) quantum dots with the effect of a capping agent. Lead sulfide quantum dots were prepared from a waveguide sol gel material with an organic-inorganic capping agent. The quantum dots were made using silica, a photoreactive methylmethacrylate group and a zirconia sol gel solution to give various concentrations of PbS quantum dots. UV-visible absorption spectra linearly increased with increasing PbS quantum dot concentration up to 10 649 ppm, after which increase was nonlinear. At room temperature, strong photoluminescence was achieved with a weak excitation light source, and the intensity increased almost linearly. This indicated that the quantum dots were distributed uniformly in the sol gel matrix. The thermal process slightly reduced the luminescence intensity. A red shift due to band gap energy was observed from 1.55 eV to 1.49 eV.