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Substituted Indazoles as Hole Transport Molecules

IP.com Disclosure Number: IPCOM000103374D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 41K

Publishing Venue

IBM

Related People

Pacansky, J: AUTHOR [+2]

Abstract

The photochemical instability of hydrazone-based hole transport molecules such as p-diethylaminobenzaldehyde diphenylhydrazone (DEH) gives rise to photoproducts in the hole transport layer which interfere with the hole transport process in organic- layered photoconductors, causing surface charges to persist even after illumination. This is a result of a photochemically- induced reaction in the charge transport layer caused by the absorption of 400-480 nm light by DEH.

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Substituted Indazoles as Hole Transport Molecules

      The photochemical instability of hydrazone-based hole transport
molecules such as p-diethylaminobenzaldehyde diphenylhydrazone (DEH)
gives rise to photoproducts in the hole transport layer which
interfere with the hole transport process in organic- layered
photoconductors, causing surface charges to persist even after
illumination.  This is a result of a photochemically- induced
reaction in the charge transport layer caused by the absorption of
400-480 nm light by DEH.

      Disclosed is a class of organic hole transport molecules,
1-substituted-3-(4-diethylamino-1-phenyl)-1,3-indazoles (see figure
below), whose long wavelength optical absorption tail in the
UV-visible spectrum is shifted to shorter wavelengths and whose
quantum yield for photochemistry is lower compared to many
hydrazone-based hole transport molecules such as DEH.  Consequently,
its use in hole transport layers provides a much more
photochemically-stable organic photoconductor.

      1-Substituted-3-(4-diethylamino-1-phenyl)-1,3-indazoles were
produced by exposing thin films of various derivatives of p-diethyl-
aminobenzaldehyde diphenylhydrazone, coated on Mylar, to 400-480 nm
light using a conveyor system for continuous feeding to the light
source.  The photoproducts, were isolated via standard
chromatographic techniques.

      Disclosed anonymously.