Charge-Carrier Dynamics in Novel Photorefractive Inorganic: Organic Nanocomposites
Paras Prasad Principal Investigator
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This project focuses on the study of basic processes associated with the photorefractive effect in a novel class of inorganic nanocrystal: polymer nanocomposites. The proposed new class of materials holds promise in that the spectral response for photorefractivity can be selectively chosen for operation at visible as well as near infra-red communication wavelengths, a feature primarily derived from the quantum confinement effect in inorganic systems will allow the photorefractive effect to be observed at low operational voltage. This novel approach to the photosensitization of polymeric materials not only offers a method by which the characteristics and processes involved in the photorefractive effect may be significantly enhanced, but also provides the opportunity to study the fundamental physical processes of photocharge generation, migration, and trapping and recombination. Photoconductivity experiments will be utilized in the characterization of the photosensitivity of the nanocomposite and mobility data will be obtained from time-of-flight experiments. The results will then be analyzed using established model, e.g. the Onsager recombination model. Photorefractive characterizations will be made using degenerate-four-wave-mixing- as well as asymmetric-two beam coupling techniques. These experiments will provide insight into several aspects of grating formation such as phase shift and the kinetics of grating growth and decay. The temerature dependence of the mobility as well as grating kinetic experiments will provide additional insight into the mechanism of trapping and detrapping of carriers.<br/>%%%<br/>The development of novel optical materials should be reviewed as having potentially a very important impact on technology, and the best properties of both inorganic and organic materials need to be exploited. Graduate and post -doctoral students trained in these areas will have excellent job prospects.