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Completed Exploratory Projects 2007
Nanowire-Nanocrystal Multiexciton Solar Cells Investigators Yi Cui, Materials Science and Engineering, Stanford University Objective This project explores a novel photovoltaic cell architecture using a network of PbSe nanowires combined with PbS nanocrystals. The aim of this project is to use the proposed structure to achieve both high photon absorption through impact ionization processes in the nanocrystals, and efficient charge transport through both the nanowire network and the nanocrystal arrays filling the void space in the nanowire scaffold. This concept is a new approach to the realization of high-efficiency thin film photovoltaics, and will require the exploration of fundamental questions, many of which will also benefit other innovative thin film technologies. Publications
Nanostructured ZnO as a Solution-Processable Transparent Electrode Material for Low-Cost Photovoltaics Investigator Alberto Salleo, Materials Science and Engineering, Stanford University Objective This study explores innovative approaches for using zinc-based oxide materials as transparent conductive films in photovoltaic devices. The proposed strategy consists of depositing a planar network of doped ZnO nanowires from solution and annealing it by laser to form a continuous film. This approach promises better conductivity and transparency properties than in unannealed nanowire networks, in addition to the advantages associated with solution processing. Laser annealing of highly-doped ZnO nanowires is a novel technique that will be investigated for the first time in this project. Plasma Activated Fuel Cells Investigator Mark A. Cappelli, Mechanical Engineering, Stanford University Objective In this project, the effects of plasma injection on the operation of a fuel cell will be studied. A nonequilibrium plasma will be generated in the inlet gases of the fuel cell via dielectric barrier discharge. Ionized gas-phase species may alter the reaction pathways at the catalytic solid-gas interface in a way that affects significantly the activation losses. Through bench top experiments and systems-level modeling, this research will determine whether the resulting change in operational efficiency can overcome the power needed to generate the plasma. The applications of plasma to fuel cells extend beyond mere efficiency gains; plasma enhancement may also be used simultaneously for internal fuel reforming. Feasibility of a Novel Photoelectrochemical Conversion Device Investigator Fritz B. Prinz, Mechanical Engineering and Materials Science and Engineering, Stanford University Objective This project envisions solar conversion systems where light is converted to electricity via charge separation and transfer through a solid-state electrolyte. The latter occurs through an ultra-thin solid state electrolyte which is capable of conducting redox couples that carry both positive and negative charges without allowing them to recombine within the confinements of the film electrolyte. To effectively screen feasible material alternatives for this project, efficient computational tools are needed for the down selection process. Therefore this project also aims to develop a computational tool to calculate the electronic structure including the band gap of nano-scale devices with practical computational resources. The simulation tool under development will use a tight binding method that is shown to be fast enough to evaluate relevant systems with reasonable accuracy. |