Design methodologies, fabrication and characterization of hybrid organic-inorganic nanoscale opto-electronic devices.

摘要

Traditional silicon based semiconductor technology has primarily relied on top-down manufacturing approach to realize devices from bulk materials. Advent of solution processible conjugated organic semiconductors and inorganic nanomaterials like quantum-dots and carbon nanotubes have opened up new avenues of hybridization for novel device structures based on bottom-up approach and self-assembly. To this end, this dissertation investigates the design methodologies and fabrication of novel opto-electronic devices like light-emitting diodes (LEDs) and photovoltaic cells, utilizing the marriage between conductive organic species, CdSe-ZnS nanocrystals, carbon nanotubes and encapsulating porous structures. For actualization of this paradigm, different hybridizational approaches were experimentally studied and demonstrated, namely (i) incorporation of CdSe-ZnS quantum-dots in a conductive organic matrix for realization of multilayered LEDs with tunability of color, reduced turn-on voltage and enhanced quantum-efficiency, (ii) self-assembled infiltration of conjugated polymers in nanoporous encapsulating templates for optical tuning and enhanced air-stability of devices based on them, (iii) fluorescent labeling of carbon nanotubes with CdSe-ZnS nanocrystals for optical visualization and micromanipulation in biologically relevant environments, and (iv) facile large scale alignment of carbon nanotubes for high-throughput device fabrication. Aforementioned investigations have been characterized using various electrical, spectroscopic and microscopic techniques to elucidate the behavioral characteristics. The research undertaken under the umbrella of this dissertation is expected to have broad implications for next-generation nanoscale opto-electronics based on hybrid organic-inorganic structures.