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Improvement of Graphite Electrical Properties by Intercalation of Organic Molecules

IP.com Disclosure Number: IPCOM000087818D
Original Publication Date: 1977-Mar-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Kaufman, FB: AUTHOR

Abstract

Attempts at improving the electronic properties of graphite have been motivated by the high intrinsic carrier mobility (~10/3/cm/2//V-sec) of this semimetal. In the past, typical inorganic intercalates, such as strong acids, halogens and alkali ions, have been used to increase the free carrier concentrations, which are of the order of 10/19//cc in the undoped materials. In at least one case, intercalation resulted in superconductivity, albeit at temperatures < 1 degree K. Unfortunately, the low stability, existence of multiple phases and ill-defined chemical reactions for these graphite intercalates have prevented systematic study or practical exploitation of these solids. However, the use of organic molecules as intercalating agents could avoid many of these severe problems.

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Improvement of Graphite Electrical Properties by Intercalation of Organic Molecules

Attempts at improving the electronic properties of graphite have been motivated by the high intrinsic carrier mobility (~10/3/cm/2//V-sec) of this semimetal. In the past, typical inorganic intercalates, such as strong acids, halogens and alkali ions, have been used to increase the free carrier concentrations, which are of the order of 10/19//cc in the undoped materials. In at least one case, intercalation resulted in superconductivity, albeit at temperatures < 1 degree K. Unfortunately, the low stability, existence of multiple phases and ill-defined chemical reactions for these graphite intercalates have prevented systematic study or practical exploitation of these solids. However, the use of organic molecules as intercalating agents could avoid many of these severe problems.

Organic donor or acceptor molecules appropriate for this purpose should be planar, have pi orbitals that are complementary in nature to those of graphite, and should possess molecular or ionic stability under conditions of intercalation. Preparation and fabrication of the intercalates involves three steps: First, pretreatment to remove contaminants from the graphite; second, a reaction step to allow intimate adsorption of the organic species onto the graphite; and, last, an annealing step to stabilize the phase produced. One or more of these steps involves evacuation or high temperature, and fabrication requi...