Fabrication of metal-oxide nanocrystals dispersed in a polymer film

Abstract

Metal-oxide quantum dots were fabricated and its confinement effect was investigated. We developed a simple method of producing metal oxide nanocrystals by reacting a polymeric precursor (PAA: Polyamic acid) with Cu or Sn. Cu or Sn films (10-30 nm thick) were coated with PI precursor (Dupont, PI2610) prepared by dissolving the polyamic acid in N-methyl-2pyrrdione. Then PAA/metal film structure was soft baked at 135℃ for 30 min and then fully cured in N2 atmosphere at 400℃ for 1hour. Respective particle size, distribution, and morphology were characterized by transmission electron microscopy (TEM). TEM micrographs showed spherical nanoparticles. By electron diffraction analysis, we found cubic structured Cu2O and tetragonal structured SnO2. The average particle diameter of Cu2O was 13 nm. That of SnO2 was 17 nm. UV-vis Spectrometer studies confirmed the confinement effects from a blueshift in the optical absorption. The optical absorption edge of Cu2O particles was observed to be blue shifted by ~ 20 nm from the bulk value of 595 nm. In case of SnO2 particles, the absorption edge was shifted by ~ 5 nm from the bulk value of 350nm.