Photoluminescent characteristics of solution-processed nanoscale copper oxide

In the present work, pure CuO nanoparticles were synthesized using the co-precipitation method, and their properties such as structural, morphological, and optical were elucidated. The obtained X-ray diffraction (XRD) patterns confirm that the synthesized CuO powders crystalize to a monoclinic phase. In addition to that, the appearance of the broad XRD peaks reflects the confinement of the particle size to nonorange. The average particle size of the synthesized CuO nanoparticles measured using field emission scanning electron microscopy (FESEM) image is 36.8 nm. Due to the size confinement to the nanoscale, the synthesized CuO nanoparticles showed a high optical band gap of 2.84 eV. Further, the emission properties of CuO measured using photoluminescence (PL) spectroscopy at an excitation wavelength of 300 nm reflects that most of the emission lies in the ultraviolet (UV) range. However, upon close investigation of the emission spectra, the peak corresponding to the blue emission was also observed. The appearance of this blue emission was the consequence of the various defects present in CuO such as oxygen vacancies and copper interstitials. The Commission Internationale de I'Eclairage (CIE) color coordinates for the blue color emitted by CuO nanoparticles is (0.15, 0.13), which lies close to the ideal blue color. Further, the synthesized CuO nanoparticles showed a high color purity of 84.71 % for blue color.