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Amino acids; Dispersion (waves); Dynamic light scattering; Light scattering; Optical properties; Photoluminescence spectroscopy; Scanning electron microscopy; Surface chemistry; Transmission electron microscopy; X ray absorption; X ray diffraction; Zinc oxide; Zinc sulfide, Burstein-Moss effects; Defect luminescence; Near band edge emissions; Orders of magnitude; Photo-luminescent properties; Scanning transmission electron microscopy; X ray absorption fine structures; Zeta potential measurements, Fourier transform infrared spectroscopy, cysteine; nanoparticle; zinc oxide, chemistry; infrared spectroscopy; Raman spectrometry; X ray diffraction, Cysteine; Nanoparticles; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis, Raman; X-Ray Diffraction; Zinc Oxide
Abstract:
Zinc oxide (ZnO) nanoparticles (NPs) were stabilized in water using the amino acid l-cysteine. A transparent dispersion was obtained with an agglomerate size on the level of the primary particles. The dispersion was characterized by dynamic light scattering (DLS), pH dependent zeta potential measurements, scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, photoluminescence (PL) spectroscopy, and X-ray absorption fine structure (EXAFS, XANES) spectroscopy. Cysteine acts as a source for sulfur to form a ZnS shell around the ZnO core and as a stabilizer for these core-shell NPs. A large effect on the photoluminescent properties is observed: the intensity of the defect luminescence (DL) emission decreases by more than 2 orders of magnitude, the intensity of the near band edge (NBE) emission increases by 20, and the NBE wavelength decreases with increasing cysteine concentration corresponding to a blue shift of about 35 nm due to the Burstein-Moss effect. © 2015 American Chemical Society.
