XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
44
T1: O–2
Structural characterization of photoactive TiO
2
/MoS
2
anodes
Joanna Banaś
1
, Anna Kot
1
, Anita Trenczek-Zając
1
, and Marta Radecka
1
1
AGH University of Science and Technology, Faculty of Materials Science and Ceramics, al. A.
Mickiewicza 30, 30-059 Krakow, Poland, e-mail: jbanas@agh.edu.pl
Miscellaneous parameters in combination with hydrothermal conditions allow to synthesize
2D material with increased interplanar distances and various number of layers. Effects related
with structural changes can be easily tracked with the use of Raman spectroscopy. Reduce the
number of layers revealed as a drop in the difference between bands E
1
2g
and A
1g
position (Fig.
1) is typical for layered architecture [1–2]. The first one (at 383 cm
–1
for bulk material)
corresponds to in-plane optical vibration of the Mo and S atoms in the basal plane. The
following (at 408 cm
–1
) reflects out-of-plane optical vibration of S atoms along the vertical axis
[2].
The aim of this work was to investigate structural properties of layered MoS2 obtained in
different conditions with the use of hydrothermal approach. As-received powders served as
sensitizers of TiO
2
-based photoanodes for PEC (PhotoElectrochemical Cell). TiO
2
/MoS
2
composites were obtained by electrochemical deposition of layered MoS
2
on TiO
2
nanotubes,
which were synthesized by anodization of Ti foils. Materials were characterized with the use of
X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Raman spectroscopy,
impedance spectroscopy, and current-voltage characteristics of PEC.
Fig. 1. Analysis of Raman spectra for MoS
2
powders synthesized hydrothermally: a) in different reaction time
(t=6, 12, 18, 24 h) and b) in time of 24 h with the use of different surfactants (Pluronic, SDBS, CTAB, PEG-1000).
The analysis of the obtained results allows us to find relationship between structural
properties of layered materials and their sensitization effect on photoelectrochemical
performance of TiO
2
-based photoanodes.
Keywords: Raman spectroscopy; layered materials; photoelectrochemical cell
Acknowledgment
This work was financed in the framework of Statutory Project for Science (Grant for Young Scientists no.
15.11.160.763, 2017) at the Department of Inorganic Chemistry, Faculty of Materials Science and
Ceramics, AGH University of Science and Technology, Krakow, Poland.
References
[1] S. A. Han et al., Nano Convergence 2 (2015) 17.
[2] K. Gołasa et al., Acta Physica Polonica A 124 (2013) 849.
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
45
T1: O–3
Automated multi-point analysis
with multi-angle photometric spectroscopy
Marcus Schulz
1
1
Application Engineer Molecular Spectroscopy, Agilent Technologies
Spectral reflection (R) and transmission (T) are fundamental measurements for
characterizing the optical properties of materials and optical coatings. Historically the complete
characterization of optical materials and coatings for precision optics has been largely
accomplished on the basis of normal and near normal incidence measurements due to the
experimental simplicity of such an approach. This simplicity, however, is not without
compromise. Normal incidence transmission measurements are typically conducted within the
sample chamber of a spectrophotometer whilst near normal reflectance measurements require
the use of a suitable reflectance accessory. A consequence of this approach is that there is never
any guarantee that reflectance and transmission measurements are made from exactly the same
patch on the sample due to sample repositioning during the significant changes in instrument
configuration between R and T measurements.
Multi-angle photometric spectroscopy (MPS) measures the reflectance and/or transmittance
of a sample across a range of angles (qi) from near normal to oblique angles of incidence (AOI).
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
46
T1: O–4
Twist sense inversion of helical structure in liquid crystals
by spectroscopy methods
Marzena Tykarska
1
, Anna Drzewicz
1
, and Michał Czerwiński
1
1
Institute of Chemistry, Military University of Technology, 00-908 Warsaw ul.gen. S. Kaliskiego 2,
Poland, e-mail: e-marzena.tykarska@wat.edu.pl
Liquid crystals are materials which molecules undergo self-organization. When chiral
molecules form liquid crystalline phases, the macroscopic helical structure is formed [1]. It is
characterized by two parameters helical pitch and helical twist sense. In compounds forming
antiferroelectric phase SmC*A the helical pitch can be right-handed (RH), left handed (LH) or
right handed at low temperatures and left handed at higher temperatures. In the last case the
twist sense inversion appears in between, see Fig. 1 for compound C
3
H
7
(HPhF) [2]. Many of
such examples are given in [3, 4].
Fig. 1. Temperature dependence on helical pitch for compound C
3
H
7
(HPhF)
The results of measurements of compounds showing helical twist sense inversion by
spectroscopy methods UV Vis, IR, VCD, ECD, NMR will be presented [5].
Keywords: liquid crystals; antiferroelectric phase; twist sense inversion
Acknowledgment
Financial support PBS/651/2016/WAT.
References
[1] S.T. Lagerwall, Ferroelectric and antiferroelectric liquid crystals, Wiley-VCH, Weinheim, 1999.
[2] M. Żurowska, R. Dąbrowski, J. Dziaduszek, K. Garbat, M. Filipowicz, M. Tykarska, W. Rejmer, K.
Czupryński, A. Spadło, N. Bennis, J.M. Otón, J. Mater. Chem. 21 (2011) 2144.
[3] M.Tykarska, M.Czerwiński, M.Żurowska, Liq. Cryst.. 38 (5) (2011) 561.
[4] M. Czerwiński, M. Tykarska, Liq. Cryst.. 41(6) (2014) 850.
[5] M. Tykarska, M. Czerwiński, Liq. Cryst.. 43(4) (2016) 462.
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