SYNTHESIS, CHARACTERIZATION AND STRUCTURE-PROPERTY INVESTIGATION OF FUNCTIONAL INORGANIC-ORGANIC HYBRID NANOMATERIALS

Abstract

Inorganic-organic nanostructured hybrid materials can be designed to achieve specific and complementary optoelectronic properties different from indivisual organic and inorganic components. The efficient coupling between organic and inorganic moieties facilitates optimization of these optoelectronic properties as single entity. Simply dispersing semiconductor nanocrystals in organic polymers permits nanocomposite formation, but usually they are prone to phase separation. For more-efficient energy transfer, charge carrier transport and correspondence between energy levels of the semiconductor nanocrystals and conducting polymers, direct interaction is necessary. Direct synthesis of semiconductor nanocrystals inside the conducting polymers matrix can help us to achive higher interfacial interaction between two components. This increases the surface-area-to-volume ratio contact between organic and inorganic moieties. Due to this advantage, energy transfer mechanism in hybrids can be tuned more efficiently for radiative or nonradiative decay. Recombination of excitons or the isolation of electrons (modulation of charge transport) by controlling the conduction band-valence band (HOMO - LUMO) level becomes more tunable in donor-acceptor materials systems. Such optoelectronic property fine-tuning in a nanostructured hybrid system can also be easily integrated into device fabrication (e.g., photovoltaic systems, light-emitting diode materials, sensors, and patterned arrays). Semiconducting polymer shell facilitates greater solubility and dispersion of the semiconductor nanocrystals in a host polymer matrix. The use of such semiconducting polymers is an interesting method for facilitating surface functionalization, nanocrystal solubility, and electrochemical II reactivity. By focusing on different chalcogenide, semiconductor nanocrystals (NCs) or quantum dots (QDs) along with low or wide band gap conducting polymers, it is possible to investigate structure-property relationship. This thesis focuses on the design, synthesis, and structure-properties of such inorganic-organic nanohybrid systems.