Synthesis, characterization, and comparative study of CdSe-TiO_2 nanowires and CdSe-TiO_2 nanoparticles

摘要

Cadmium selenide (CdSe) quantum dots in selective size were prepared by using inverse micelle technique without the presence of trioctylphosphine (TOP) and characterized by UV-visible absorption, Fourier transform infrared (FTIR) and photoluminescence (PL) spectroscopic studies. The UV-visible absorption and PL studies showed strong quantum confinement effect and bandgap energy about 2.1 eV in CdSe quantum dots. Particle size and electron diffraction analyses in high resolution transmission electron microscopy (HRTEM) confirmed the formation of CdSe crystalline particles in the range of 3.1-3.9 nm. These wide bandgap CdSe quantum dots were used for the preparation of CdSe-TiO_2 nanocomposites of TiO_2 nanoparticles and TiO_2 nanowires. HRTEM images of the CdSe-TiO_2 nanowires (CdSe-TNW) and the CdSe-TiO_2 nanoparticles (CdSe-TNP) composites revealed the uniform, layered distribution of CdSe quantum dots on TiO_2 nanoparticles and on TiO_2 nanowires in different dimensions. Further, the differences in the dimensional distributions and optical properties of CdSe-TNW and CdSe-TNP nanocomposites were investigated for their applications to TiO_2 sensitized solar cells.