Vibrational Overtone Spectra in Polymeric Thin Films

1991 ◽  
Vol 228 ◽  
Author(s):  
Andrew Skumanich ◽  
Christopiier Moylan
Keyword(s):  
Thin Films ◽  
Wavelength Region ◽  
Organic Thin Films ◽  
Precise Determination ◽  
Polymeric Thin Films ◽  
Enhanced Sensitivity ◽  
Photothermal Deflection Spectroscopy ◽  
Vibrational Overtone ◽  
Broad Energy Range ◽  
Long Fibers

ABSTRACTWith the enhanced sensitivity of Photothermal Deflection Spectroscopy (PDS), vibrational overtone spectra have been obtained in organic thin films for the first time, covering the range from the near IR to the visible (0.4 - 2 eV). The absorption spectra of polycarbonate, for instance, exhibits C-I1 stretch modes for Δn> I where n is the vibrational quantum level. Previous measurements were constrained to either long fibers, which pose the problem of various scattering losses not related to absorption, or to a restricted wavelength region in the visible accessible by dye laser sources. The unparalleled sensitivity of PDS allows precise determination of frequency, lineshape and intensity of the various modes, even for films ∼10μm thick over a broad energy range. The overtone spectra can be used as a probe of various basic molecular properties. In a manner similar to NMR spectroscopy, it is possible to study specific atomic bonds.

Highly Sensitive Absorption Measurements in Organic Thin Films: Charge Transfer Complexes and Light-Induced Changes

1991 ◽  
Vol 228 ◽  
Author(s):  
Andrew Skumanich
Keyword(s):  
Thin Films ◽  
Charge Transfer ◽  
Energy Levels ◽  
Organic Thin Films ◽  
Organic Films ◽  
Charge Transfer Complexes ◽  
Weak Charge ◽  
Polymeric Thin Films ◽  
Photothermal Deflection Spectroscopy ◽  
Induced Changes

ABSTRACTUsing the sensitive absorption technique of Photothermal Deflection Spectroscopy (PI1S) it is possible to detect subtle spectral features in the absorption spectra of polymeric thin films that cannot be detected by other means. This paper describes observations of weak charge-transfer complex (CIC) formation and also light-induced changes in various organic films. The filns studied were those commonly used as charge transport materials in organic photoconductors, comprised of a small transport molecule and a polymer binder. The optically measured CTC bands can be used to establish single electron energy levels of the constituents. Reproducible photo-induced changes are manifest both in the strong UV transitions as well as in the “sub-gap” absorption and appear to be correlated with the photo-chemical stability of the constituents. The light-fatigue has both a reversible as well as irreversible component.

Growth and Characterization of Organic Polymeric Thin Films From Isopropanol by PECVD.

2009 ◽  
Vol 1242 ◽  
Author(s):  
J. O. Martínez-Gutiérrez ◽  
G. Romero-Paredes ◽  
R. Peña-Sierra ◽  
A. Ávila-García ◽  
G. Juárez-Díaz
Keyword(s):  
Thin Films ◽  
Visible Region ◽  
Chemical Vapor ◽  
Ammonium Hydroxide ◽  
Organic Thin Films ◽  
Optical Bandgap ◽  
Polymeric Thin Films ◽  
Force Microscopy ◽  
Atomic Force

ABSTRACTPolymerized organic thin films were synthesized on a variety of substrates by Plasma Enhanced Chemical Vapor Deposition (PECVD) technique using isopropanol as precursor. Hydrogen peroxide, ammonium hydroxide, and iodine dissolved in isopropanol were used as dopants and chlorobenzene as copolymerization precursor. The structural, optical and electrical properties of the films were studied as functions of the dopant type and concentration.The polymeric films were characterized by variable angle ellipsometry (VAE), atomic force microscopy (AFM), Fourier Transform Infrared spectroscopy (FTIR), ultraviolet-visible transmission spectroscopy and photoluminescence. The electrical film behavior was explored by the four points probe method.The growth rate, refractive index, optical bandgap, chemical structure and resistivity of the films strongly depend on the concentration and type of dopant added. The AFM microphotographs showed smooth surfaces with RMS roughness less than 10 nm. The optical bandgap values of the films were in the range of 2.6 to 3.26 eV, the resistivity was in the order of 103 – 104 ohm-cm. The photoluminescence response of the polymerized films was obtained in the visible region, by exciting with a UV laser.

Absorption phenomena in organic thin films for solar cell applications investigated by photothermal deflection spectroscopy

2005 ◽  
Vol 40 (6) ◽  
pp. 1413-1418 ◽  
Author(s):  
L. Goris ◽  
K. Haenen ◽  
M. Nesládek ◽  
P. Wagner ◽  
D. Vanderzande ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Cell ◽  
Organic Thin Films ◽  
Photothermal Deflection Spectroscopy ◽  
Photothermal Deflection

Optical and Morphological Characterization of PTCDI-C13

2008 ◽  
Vol 1091 ◽  
Author(s):  
Marco Stella ◽  
Fernando Villar ◽  
Fredy Enrique Rojas ◽  
Mónica Della Pirriera ◽  
Cristobal Voz ◽  
...  
Keyword(s):  
Thin Films ◽  
Substrate Temperature ◽  
High Vacuum ◽  
Organic Thin Films ◽  
Morphological Characterization ◽  
Force Microscopy ◽  
Vacuum Chambers ◽  
Photothermal Deflection Spectroscopy ◽  
Atomic Force ◽  
Deposition Parameters

AbstractThe organic photovoltaic technology has developed much in the last few years thanks to the optimization of the solar cell geometry and, specially, to the research for new performing materials. Nevertheless, much work has still to be done in order to better know the real mechanisms regulating the function of such novel class of semiconductors. The study of thin-film micro-structure, and the influence of the deposition parameters on it, is an important issue in order to obtain best optical and electrical properties. Thermal evaporation in high-vacuum chambers is the more suitable deposition technique to obtain organic thin-films with well organize molecular structure. Deposition parameters such as the substrate temperature and deposition rate may have some important effect on the molecules ordering. In this paper the effects of substrate temperature on structural and optical properties have been studied for N,N′-ditridecyl perylene diimide (PTCDI-C13) thin-films. Four samples have been deposited at 30, 60, 90 and 120°C substrate temperature and their absorption has been investigated by photothermal deflection spectroscopy (PDS) and transmittance spectroscopy. Moreover, simulations of the transmittance spectra have been calculated in order to obtain the optical constants n and k. Finally atomic force microscopy (AFM) has been employed to analyze the superficial morphology of the thin-films.

Polarized Fluorescence of Spin-coated Polymeric Thin Films

2007 ◽  
Vol 2 (2) ◽  
pp. 257-264
Author(s):  
Satoko Nishiyama ◽  
Masahiro Tajima ◽  
Yasuhiko Yoshida
Keyword(s):  
Thin Films ◽  
Polarized Fluorescence ◽  
Polymeric Thin Films

The effects of metallic contacts on the lasing characteristics of organic thin films

2020 ◽  
Vol 13 (4) ◽  
pp. 866-872
Author(s):  
HAO Ya-ru ◽  
◽  
◽  
DENG Zhao-qi
Keyword(s):  
Thin Films ◽  
Organic Thin Films ◽  
Metallic Contacts

Carbon Monoxide Sensing Technologies

2021 ◽  
Keyword(s):  
Thin Films ◽  
Carbon Nanotubes ◽  
Carbon Monoxide ◽  
Metal Oxides ◽  
Electrochemical Sensors ◽  
Colorimetric Detection ◽  
Infrared Sensors ◽  
Polymeric Thin Films ◽  
Semiconducting Metal Oxides ◽  
Book Covers

The book covers the sensing and monitoring of poisonous carbon monoxide pollution in the environment. The sensors covered include semiconducting metal oxides, carbon nanotubes, conducting polymeric thin films, sensors based on colorimetric detection, non-dispersive infrared sensors, electrochemical sensors and photoacoustic detectors.

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