Metal and metal oxide nanostructures for applications in organic solar cells and memory devices

Abstract

The devices based on inorganic semiconductors are widely used to fabricate gadgets newlinesuch as laptops, mobile phones, digital cameras, televisions and music players which newlinemake our daily life simple and comfortable. Inorganic semiconductor devices exhibit newlinesuperior performance and good stability. However, high production cost and complex newlinemanufacturing steps involved in inorganic semiconductor technologies have led to the newlinedevelopment of an alternative technology called organic electronics. Various devices newlinesuch as solar cells, light emitting diodes, transistors and memory devices have been newlinedemonstrated using thin films of organic semiconductors. The advantages of organic newlineelectronic devices include low production cost, solution based manufacturing, light newlineweight and mechanical flexibility. However, the current performance and life time of newlinethese devices are not adequate for practical applications. Present thesis focuses on newlineimproving the performance of organic solar cells (OSCs) and memory devices by newlineutilizing the unique properties of metal and metal oxide nanostructures, respectively. newlinePlasmonic effects of metal nanostructures have been widely explored to increase newlinelight absorption in OSCs. High absorption enhancement in a broad spectral range is newlinehighly desirable to boost the efficiency of OSCs. In the present thesis, utilizing newlineplasmonic effects of multi-positional Ag nanostructures is demonstrated as a promising newlinestrategy to achieve broadband light absorption enhancement in OSCs. In the first part of newlinethe work, the influence of size, shape and location of Ag nanostructures on the active newlinelayer absorption was investigated using finite-difference time-domain (FDTD) newlinesimulations. High enhancement factors around 1.52 and 1.58 were obtained when Ag newlinenanospheres and nanocubes were incorporated in the top portion of 80 nm thick newlinePTB7:PC70BM active layer, respectively. newline