2 research outputs found
Patterning of Magnetic Bimetallic Coordination Nanoparticles of Prussian Blue Derivatives by the LangmuirāBlodgett Technique
We report a novel method to prepare patterns of nanoparticles
over
large areas of the substrate. This method is based on the adsorption
of the negatively charged nanoparticles dispersed in an aqueous subphase
onto a monolayer of the phospholipid dipalmitoyl-l-Ī±-phosphatidylcholine
(DPPC) at the airāwater interface. It has been used to prepare
patterns of nanoparticles of Prussian blue analogues (PBA) of different
size (K<sub>0.25</sub>NiĀ[FeĀ(CN)<sub>6</sub>]<sub>0.75</sub> (NiFe),
K<sub>0.25</sub>NiĀ[CrĀ(CN)<sub>6</sub>]<sub>0.75</sub> (NiCr), K<sub>0.25</sub>NiĀ[CoĀ(CN)<sub>6</sub>]<sub>0.75</sub> (NiCo), Cs<sub>0.4</sub>CoĀ[CrĀ(CN)<sub>6</sub>]<sub>0.8</sub> (CsCoCr), and Cs<sub>0.4</sub>CoĀ[FeĀ(CN)<sub>6</sub>]<sub>0.9</sub> (CsCoFe)). The behavior of DPPC
monolayer at the airāwater interface in the presence of the
subphase of PBA nanoparticles has been studied by the compression
isotherms and Brewster angle microscopy (BAM) images. Atomic force
microscopy (AFM) of the transferred films on mica substrates shows
that patterns of the nanoparticles are observed for a 10<sup>ā4</sup> M concentration of the subphase, based on the nanoparticle precursors,
at surface pressures between 1 and 6 mN/m and transfer velocities
from 10 to 80 mm/min. Vertical, horizontal, or tilted fringes of the
nanoparticles with respect to the transfer direction can be obtained
depending on the transfer velocity and surface pressure
White Light-Emitting Electrochemical Cells Based on the LangmuirāBlodgett Technique
Light-emitting electrochemical
cells (LECs) showing a white emission
have been prepared with LangmuirāBlodgett (LB) films of the
metallosurfactant bisĀ[2-(2,4-difluorophenyl)Āpyridine]Ā[2-(1-hexadecyl-1<i>H</i>-1,2,3-triazol-4-yl)Āpyridine]ĀiridiumĀ(III) chloride (<b>1</b>), which work with an air-stable Al electrode. They were
prepared by depositing a LB film of <b>1</b> on top of a layer
of polyĀ(<i>N</i>,<i>N</i>ā²-diphenyl-<i>N</i>,<i>N</i>ā²-bisĀ(4-hexylphenyl)-[1,1ā²-biphenyl]-4,4ā²-diamine
(pTPD) spin-coated on indium tin oxide (ITO). The white color of the
electroluminescence of the device contrasts with the blue color of
the photoluminescence of <b>1</b> in solution and within the
LB films. Furthermore, the crystal structure of <b>1</b> is
reported together with the preparation and characterization of the
Langmuir monolayers (Ļā<i>A</i> compression
isotherms and Brewster angle microscopy (BAM)) and LB films of <b>1</b> (IR, UVāvis and emission spectroscopy, X-ray photoelectron
spectroscopy (XPS), specular X-ray reflectivity (SXR), and atomic
force microscopy (AFM))