Synthesis and characterization of isonipecotic acid-modified Mn-doped ZnO nanoparticles
L. Jiménez-Hernándeza,b, O. Estévez-Hernándeza,b, M. Hernández-Sáncheza, E. Reguerab
a
Instituto de Ciencia y Tecnología de Materiales (IMRE), Universidad de La Habana, Cuba.
a
Centro de Investigación en Ciencia Aplicada y Tecnología de Avanzada, IPN, Legaría 694,
México, DF
Email: linnavelhdez@gmail.com
Keywords: Zinc oxide; Mn doping; Semiconductors; Isonipecotic acid.
ZnO nanoparticles are an attractive choice as host semiconductor due to its low toxicity, low
cost, stability and high transparency in the visible wavelength [1]. Doped nanomaterials have
many interesting and unique properties that are useful for important technological applications
[2-4]. The use of nanocomposites in biosensing requires a careful design. The conjugation of
biomolecules to ZnO nanostructures includes a functionalization step by coating the surface
with an appropriated ligand in order to prevent aggregation of the particles. The surface
coverage leads to electronic passivation, which enhances room temperature photoluminescence
of the nanomaterial that could then be used as fluorescent probes for the study of biological
samples.
In doped ZnO nanostructures with transition metals have been observed a variation in the
magnetic and optical properties respect to ZnO [5]. Manganese doped zinc oxide (ZnO1-xMnx)
has attracted great interest because of possible applications in the field of short-wave magnetooptical devices [6]
In this work, we have prepared isonipecotic acid (IA)-surface modified Mn-doped ZnO
nanoparticles. Nanostructures were characterized by X-ray diffraction, transmission electron
microscopy, FTIR spectroscopy, thermal gravimetric analysis, energy dispersive X-ray analysis
and X-ray photoelectron spectroscopy. X-ray diffraction measurement shows highly crystalline
material with nanostructures size of about 3-4 nm. Their optical properties were also evaluated
from solid UV-Vis and photoluminescence measurements.
The FTIR spectrum indicates the presence Zn-O characteristic band (398 cm-1). When
nanoparticles are functionalized whit IA, we observed new bands at 2919, 2850, 1630, 1400,
1244 and 1154 cm-1 which correspond to the presence of this ligand. In XRD, characteristic
hexagonal wurtzite-type ZnO peaks are observed. We obtained the same results in the case of IA
functionalized nanoparticles. This fact suggests that after functionalization, crystallinity and
structure of the material are maintained. Size and morphology of NPs where determined by
mean of TEM studies, obtaining 3 to 4 nm spherical and hexagonal geometry distribution. The
XPS signal Mn 2p 3/2 shows two picks at 641.4 and 644.1 eV, which are characteristic of Mn2+
and Mn4+ respectively. We also observed changes in the ZnO band gap after Mn-doping.
Finally, the magnetic properties of the Cu-doped ZnO nanoparticles were studied and no
hysteresis loops were observed.
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