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The influence of photosensitizers on the photorefractivity in poly[methyl-3-(9-carbazolyl)propylsiloxane]-based composites

Paper ID Volume ID Publish Year Pages File Format Full-Text
28968 44109 2009 6 PDF Available
Title
The influence of photosensitizers on the photorefractivity in poly[methyl-3-(9-carbazolyl)propylsiloxane]-based composites
Abstract

We investigated the photosensitizers effect on the photorefractive (PR) properties in five poly[methyl-3-(9-carbazolyl)propylsiloxane] (PSX-Cz)-based PR composites which were doped with various photosensitizers having each different electron affinity, such as 2,4,5,7-tetranitro-9H-fluorine-9yilden malonitrile (TeNFM), 2,4,7-trinitro-9-fluorenone (TNF), 9-dicyanomethylene-2,4,7-trinitro-fluorenone (TNFM), tetracyanoethylene (TCNE), and 7,7,8,8-tetracyanoquinnodimethane (TCNQ). At 632.8 nm, photo-charge generation efficiencies, photoconductivities, space charge field, four wave mixing diffraction efficiencies, and PR grating buildup times were measured as a function of external electric field. The photo-charge generation, which is dependent on the light absorption, was achieved through the charge transfer (CT) complexes between the PSX-Cz and each of the photosensitizers. The photon energy of the CT transition decreased with increasing electron affinity of the photosensitizer. In composites doped with TeNFM, TNF, and TNFM, the space charge field (Esc) increased as the photo-charge generation efficiency increased; the grating buildup in these composites is rate-limited by the photo-charge generation speed. In sample doped with TCNE, and TCNQ, the hole mobility was reduced due to the larger amount of photosensitizer anion traps produced by photoreduction of the photosensitizer. Then, the grating buildup speed became hole mobility limited, and smaller buildup rates were observed. The magnitude of space charge field was sustained as the charge and trap density increased. In all composites, the refractive index modulation is increased with the magnitude of space charge field.

Keywords
Photosensitizer; Photo-charge generation; Photocurrent; Space charge field; PR grating buildup time
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The influence of photosensitizers on the photorefractivity in poly[methyl-3-(9-carbazolyl)propylsiloxane]-based composites
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 201, Issues 2–3, 25 January 2009, Pages 222–227
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us