(447b) Development of a Scalable Bottom-up Nanomanufacturing Platform for Highly Efficient Photovoltaics

Solar energy is clean, abundant, and renewable, yet it is vastly under-utilized in the current world. Although crystalline silicon solar cells are the premier candidate for renewable and environmentally friendly solar energy conversion, high manufacturing cost has prevented such cells from economically competing with the combustion of fossil fuels as a source of electricity on a large scale. Thus, finding novel fabrication techniques for silicon-based solar energy conversion that will increase efficiency and lower manufacturing cost is a primary challenge in meeting the world's future energy needs in a renewable fashion. We have developed a scalable bottom-up nanomanufacturing platform for mass-producing highly efficient photovoltaics by exploring effective photon management using surface-plasmon-enabled transparent conducting electrodes and subwavelength antireflective coatings. In this methodology, spin-coated colloidal crystals with wafer-sized areas, remarkably large domain sizes, and unusual nonclose-packed structures are used as templates to create periodic metallic nanohole arrays and subwavelength moth-eye antireflection coatings. The resulting metallic nanohole arrays exhibit high and tunable optical transmission and high conductivity, promising as transparent conducting electrodes for flexible photovoltaics. The subwavelength-structured moth-eye antireflection coatings show much improved broadband antireflective properties than traditional quarter-wavelength coatings. This novel spin-coating platform combines the simplicity and cost benefits of bottom-up self-assembly with the scalability and compatibility of standard top-down microfabrication. Besides silicon cells, the nanomanufacturing platform can be easily extended to other photovoltaic technologies, such as dye-sensitized cells, organic photovoltaics, and thin-film cells.