Interaction of l-Cysteine with ZnO: Structure, Surface Chemistry, and Optical Properties

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.

Influence of Organic Ligands on the Colloidal Stability and Removal of ZnO Nanoparticles from Synthetic Waters by Coagulation

“…The broad peak in all flocs at 3327 cm −1 is due to the polar interaction of Fe ions and their hydrolyzed products, which tend to form complexes with metal ions [59]. The disappearance of S-H band at 2548 cm −1 in S7 indicates the formation of covalent bonds between thiols and Zn 2+ onto the NPs surface [60]. The shift in the peak of C=O from 1263 to 1250 cm −1 further clarified that carboxyl, hydroxyl, and aromatic ester groups could be involved in complex coordination with metal ions during adsorption of the target pollutants [24,25].…”

Surface-specific visible light luminescence from composite metal oxide nanocrystals

“…The quest for luminescent materials of sufficient availability, low price, and biocompatibility is at the heart of nanomaterials research and development with applications in areas such as sensing, lighting, medicine, nanoparticle transport, and the detection of electromagnetic fields [1][2][3][4][5][6]. Perhaps the most commercially important application of luminescent materials is in solid-state lighting (SSL) devices based on blue and near-UV light-emitting diodes (LEDs) [1,6].…”

“…Current commercial SSL downconverters use rareearth phosphors such as Ce 3? or Eu 2? embedded in oxide or nitride particles [3,4]. To reduce multiple scattering events and improve performance, there has been a drive to reduce particle size.…”

“…Another class of materials system is characterized by dopants (e.g., rare-earth ions) embedded in an inorganic particle which act as luminescence centers (Fig. 1) [3,4]. In some wide band gap semiconductors, significant luminescence can even be observed in undoped materials due to the presence of intrinsic defects [20][21][22][23].…”

Capillary Electrophoresis Analysis of Metal/Metalloid Oxide Nanoparticles in Water: Method Development for the Enhancement of UV Detection Sensitivity

“…The Lagergren's pseudo-first order rate equation had previously been used to describe liquid-solid adsorption systems. [227] Its linear form is expressed as:…”