This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
0933838 Honsberg
The cost of solar cells must be reduced by a factor of two in order to achieve grid parity. There are a number of new technologies which can achieve this goal, including advanced silicon, thin film (CdTe or CIGS), organic solar cells, or, in the longer term, nanostructured photovoltaics. A commonality among these systems is the predominance of transport mechanisms across disordered/ordered interfaces that control the device performance. Existing modeling programs and approaches do not model such effects, requiring a particle-based approach such as Monte-Carlo modeling, which can accommodate hopping transport, recombination, and opto-electronic processes. In addition, the calculations are complicated by the long time scales required for photovoltaic applications, making a multiscale approach essential. The goal of this project is to develop a novel modeling approach to simulating and understanding materials and interfaces where ?hopping? transport controls the transport and recombination, and then experimentally verify and demonstrate the ability to match and predict behavior of novel solar cells. The research will optimize two specific experimental systems (a-Si/Si and organic/Si) and demonstrate the ability to achieve both transport and low recombination across such interfaces. Future goals are to use the tool for other solar cell approaches and materials.
The proposal has several scientific novelties as its intellectual merits. One scientific advance is the development of a multi-scale particle-based, Monte Carlo approach suitable for modeling disordered/ordered material interfaces. The improved understanding of these interfaces will be used to develop a match between simulated and experimental minority carrier lifetime curves of a-S/Si and organic/Si interfaces, and then develop optimized solar cells based on these interfaces. In addition to new models, the final scientific advances are to identify approaches to controlling the interface and demonstration of improved solar cells using this understanding, and allowing development of novel solar cell structures.
The project has substantial broader impacts. First, it addresses a limiting issue for a range of novel solar cell approaches, from existing commercial devices to novel nanostructured, organic or dye-sensitized devices, allowing new, higher efficiency and lower cost photovoltaic approaches. In addition, it will provide unique educational opportunities beyond the research training afforded to the graduate student involved with the project. The collaboration of different groups will be formalized through a class on photovoltaics, which combines the viewpoints and expertise of the different groups. The collaboration will result in a ?simplified? Monte Carlo simulator that allows visualization of the transport in such complex structures. It will be added to the existing photovoltaic educational website developed by the PIs, which attracts about 1,000 visits a day.
