This Nanoscale Exploratory Research (NER) proposal was submitted in response to the solicitation "Nanoscale Science and Engineering" (NSF 02-148). The project undertakes an exploratory study of spin injection and transport in organic and polymeric conductors. The approach is to fabricate organic heterostructures, employing solid-state magnetic electrodes as a source of spin polarized carriers, and manipulate the nanoscale interfacial properties using molecular self-assembly and related techniques. Spin will be injected into semiconducting and conducting polymer/organic thin films. Several specific systems consistent with "exploratory" time scales and support levels, including the organic analog of giant magnetoresistance, spin-injected organic/polymer light-emitting diodes, and tunneling from magnetic nanocrystals through organic layers will be addressed. In these systems, the interface is judged to be of critical importance since it controls injection characteristics through the electronic barrier height in the case of electronic charge, and spin-scattering characteristics in terms of magnetic electrodes. It is anticipated that interfacial control will be afforded by organic systems to manipulate spin-injection properties through the use of interfacial self-assembled monolayers, and surface doping of the barrier polymer by chemical or electrochemical means. %%% The project addresses basic exploratory research issues in a topical area of materials science with high technological relevance; it is considered a high risk/high pay-off activity. Conducting polymers and molecular organics are rapidly becoming technologically important materials because of their unique fusion of semiconducting electronic properties with the flexibility of organic/polymeric materials. A wide variety of electronic devices have been demonstrated with organic materials, such as light-emitting diodes, laser diodes, and field-effect transistors. The advantages of resulting 'plastic' electronic devices include ease of fabrication, scalability, and molecular-level control of interfacial morphology and electronic characteristics. The project encompasses the research and education theme of Nanoscale Structures, Novel Phenomena, and Quantum Control. An important feature of the program is the integration of research and education through the training of students in a fundamentally and technologically significant area. The project is expected to have broad impact by providing unique educational opportunities and basic knowledge critical to potential development of organic spintronic devices having advantages of both organic electronics and solid-state spintronics. The project is jointly supported by the MPS/DMR/EM and MPS/DMR/POL programs. ***
