Optical Degradation of Poly(P-PHENYLENE VINYLENE)

1995 ◽  
Vol 413 ◽  
Author(s):  
S. K. So ◽  
M. H. Chan ◽  
C. S. Hon ◽  
Louis M. Leung
Keyword(s):  
Optical Properties ◽  
Infrared Spectroscopy ◽  
Double Bond ◽  
Laser Irradiation ◽  
Phenylene Vinylene ◽  
Conjugation Length ◽  
Photo Oxidation ◽  
Photothermal Deflection Spectroscopy ◽  
Optical Irradiation ◽  
Photothermal Deflection

ABSTRACTThe influence of laser irradiation on an electroluminescent polymer, poly(2,5-di-n-hexyloxy-l,4- phenylene vinylene) is studied. Photoluminescence, infrared spectroscopy, and photothermal deflection spectroscopy were used to identify changes in the optical properties of the polymer after laser irradiation. It is found that optical irradiation leads to the opening of the vinyl double bond and decrease in conjugation length. Photo-oxidation of the polymer is believed to be responsible for the optical degradation of the polymer.

scholarly journals Photothermal Deflection Spectroscopy Study of Nanocrystalline Si (nc-Si) Thin Films Deposited on Porous Aluminum with PECVD

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
S. Ktifa ◽  
M. Ghrib ◽  
F. Saadallah ◽  
H. Ezzaouia ◽  
N. Yacoubi
Keyword(s):  
Optical Properties ◽  
Energy Gap ◽  
Chemical Vapor ◽  
Nanocrystalline Silicon ◽  
Porous Aluminum ◽  
Force Microscopy ◽  
Photothermal Deflection Spectroscopy ◽  
Atomic Force ◽  
Photothermal Deflection ◽  
Morphology Characterization

We have studied the optical properties of nanocrystalline silicon (nc-Si) film deposited by plasma enhancement chemical vapor deposition (PECVD) on porous aluminum structure using, respectively, the Photothermal Deflection Spectroscopy (PDS) and Photoluminescence (PL). The aim of this work is to investigate the influence of anodisation current on the optical properties of the porous aluminum silicon layers (PASL). The morphology characterization studied by atomic force microscopy (AFM) technique has shown that the grain size of (nc-Si) increases with the anodisation current. However, a band gap shift of the energy gap was observed.

Electronic and Optical Properties of a-Si1−xCx:H Films Produced From Admixtures of Silane and Ditertiarybutylsilane

1994 ◽  
Vol 336 ◽  
Author(s):  
K. Gaughan ◽  
J.M. Viner ◽  
P.C. Taylor
Keyword(s):  
Electrical Conductivity ◽  
Silicon Carbide ◽  
Optical Properties ◽  
Chemical Vapor Deposition ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Photothermal Deflection Spectroscopy ◽  
Optical And Electronic Properties ◽  
Photothermal Deflection

ABSTRACTWe investigated the optical and electronic properties of amorphous silicon carbide (a-Si1−xCx:H) films produced by plasma enhanced chemical vapor deposition from admixtures of silane and ditertiarybutylsilane [SiH2 (C4H9) 2 or DTBS] using photothermal deflection spectroscopy, electrical conductivity and its temperature dependence as well as photoconductivity. These a-Si1−xCx:H films exhibit low Urbach energies and high photoconductivities similar to films produced with other carbon feedstock sources. We also present our results for hydrogen diluted a-Si1−xCx:H films using DTBS as the carbon feedstock source.

Stability of PPV Derivatives: The Effect of Side Group Functionalities

1995 ◽  
Vol 413 ◽  
Author(s):  
B. H. Cumpston ◽  
K. F. Jensen ◽  
F. Klavettert ◽  
E. G. J. Staring ◽  
R. C. J. E. Demand
Keyword(s):  
Double Bond ◽  
Singlet Oxygen ◽  
Degradation Pathway ◽  
Phenylene Vinylene ◽  
Conjugation Length ◽  
Trans Stilbene ◽  
Thin Polymer ◽  
Singlet Oxygen Reaction ◽  
Semi Empirical

ABSTRACTWe have identified excited-state singlet oxygen as a reactive intermediate in the solid state photo-oxidation of two poly(p-phenylene vinylene) (PPV) derivatives, poly(2,5-bis(5,6- cholestanoxy)-1,4-phenylene vinylene) (BCHA-PPV) and poly(2-methoxy,5-(2'-ethyl-hexoxy)- 1,4-phenylene vinylene) (MEH-PPV). Singlet oxygen is photosensitized via energy transfer from the polymer and undergoes 1,2-cycloaddition across the electron-rich vinyl double bond in the backbone of the polymer resulting in the formation of highly oxidized species such as esters. Volatile carbonyl species are also formed, and, consequently, the film thins. This degradation pathway occurs when the polymer film is exposed in air to light having energy above the bandgap of the polymer, from either a low-pressure UV mercury lamp or an Ar+ laser operating at 514 or 457 nm. Interestingly, the singlet oxygen reaction does not take place in model compounds with similar structures such as trans-stilbene. In an effort to understand which properties of the polymer make it susceptible to singlet oxygen attack, we have studied the effect of conjugation length and side groups on the reactivity of thin polymer films. Specifically, the role of electron withdrawing groups, steric protection of the vinyl double bond, and conjugation length effects have been investigated using both FrIR spectroscopy and semi-empirical computational chemistry calculations.

Optical properties of Microcrystalline Silicon determined by Spectroscopic Ellipsometry and Photothermal Deflection Spectroscopy

2002 ◽  
Vol 715 ◽  
Author(s):  
Kyung Hoon Jun ◽  
Helmut Stiebig ◽  
Reinhard Carius
Keyword(s):  
Optical Properties ◽  
Spectroscopic Ellipsometry ◽  
Volume Fraction ◽  
Large Deviation ◽  
Effective Medium Theory ◽  
Dense Medium ◽  
Medium Theory ◽  
Enhanced Absorption ◽  
Photothermal Deflection Spectroscopy ◽  
Photothermal Deflection

AbstractThe effect of the microstructure and bonded hydrogen on the optical properties of microcrystalline films (μc-Si:H) was investigated by Spectroscopic Ellipsometry (SE) and Photothermal Deflection Spectroscopy (PDS). On samples with a high crystalline volume fraction we studied the reason for a large deviation of absorption coefficient in the energy range between 1.6 eV and 3.2 eV from the value predicted by effective medium theory. This enhancement can be attributed to scattering by the inhomogeneity of μc-Si:H, which is investigated by the introduction of the dense medium radiative transfer formalism to an optical scattering simulation. Further, we suggest strain as a reason for the enhanced absorption in highly crystalline μc-Si:H.

Optical properties of TiO2 thin films estimated by photothermal deflection spectroscopy

2003 ◽  
Vol 74 (1) ◽  
pp. 863-865 ◽  
Author(s):  
S. Ogawa ◽  
K. Mori ◽  
H. Natsuhara ◽  
T. Ohashi ◽  
R. Sakakiyama ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Tio2 Thin Films ◽  
Photothermal Deflection Spectroscopy ◽  
Photothermal Deflection

Optical properties of CdTe thin films studied by photothermal deflection spectroscopy

1983 ◽  
Vol 102 (3) ◽  
pp. 259-263 ◽  
Author(s):  
J.G. Mendoza-Alvarez ◽  
B.S.H. Royce ◽  
F. Sánchez-Sinencio ◽  
O. Zelaya-Angel ◽  
C. Menezes ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Photothermal Deflection Spectroscopy ◽  
Cdte Thin Films ◽  
Photothermal Deflection

Optical Properties of Microcrystalline Silicon

1989 ◽  
Vol 164 ◽  
Author(s):  
Martin Ingels ◽  
Martin Stutzmann ◽  
Stefan Zollner
Keyword(s):  
Optical Properties ◽  
Annealing Temperature ◽  
Structural Information ◽  
Optical Measurements ◽  
Microcrystalline Silicon ◽  
Grain Sizes ◽  
Photothermal Deflection Spectroscopy ◽  
Suitable Combination ◽  
Photothermal Deflection ◽  
Hydrogenated Amorphous

AbstractOptical properties of undoped, microcrystalline silicon are investigated by photothermal deflection spectroscopy, spectroscopic ellipsometry and Raman scattering. Samples are prepared by recrystallization of hydrogenated amorphous silicon in the temperature range 680 – 900°C. The increase of grain sizes with increasing annealing temperature and the disappearance of amorphous tissue lead to noticeable changes in the observed spectra. It is argued that much of the pertinent structural information of μc-Si can be obtained by a suitable combination of optical measurements alone.

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