Low-cost and earth-abundant nanocrystal synthesis for solar energy conversion and thermoelectric device applications

Robert B Balow, Purdue University


In as little as 35 years, the human population is expected to increase to 8.7 billion, resulting in an increasing demand for energy. This ever-growing energy crisis will be met in the short term using a rapidly diminishing supply of non-renewable and unsustainable fossil fuels such as coal, natural gas and oil. In the long term, additional energy from sustainable and renewable sources must be implemented and improved to supplement the current global energy infrastructure to sustain future energy needs. Many options are available but two main strategies paramount in accomplishing this goal are low-cost and clean electricity generation through solar cells and reclamation of waste heat energy. The most direct, clean and potentially efficient energy production method is through the use of photovoltaic devices, which directly converts solar radiation into electricity. Current industrially viable technologies consist of silicon-based solar cells capable of producing electricity at approximately 15% efficiency; however, efficiencies as high as about 87% can theoretically be obtained using a multiple junction approach. Nevertheless, end user limitations of solar energy production exist not in device efficiency and cost of materials, but rather in the final cost of electricity produced, which includes many factors such as manufacturing and installation costs, lifetime of the modules, maintenance and upkeep costs and “balance of systems” costs (energy storage, inverters, etc.). Significant cost reduction can be realized through use of novel thin film material systems capable of high-throughput manufacturing methods currently unavailable for commercialized silicon solar cells. Reclamation of waste heat has significant implications in the energy sector as well. As much as 50% of energy consumed by the U.S. industrial sector is predicted to be lost as waste heat. Thermoelectric (TE) materials offer a reliable, clean and simple solution. Unfortunately, traditionally low conversion efficiencies has greatly hindered the widespread use of TEs, but the recent discovery of nanostructured TE materials has spurred considerable improvements in performance leading to device efficiencies capable of 10–20% efficiency. Integration of nanoparticle (NP) based materials presents a potential solution for both of the limiting factors of photovoltaic and TE devices. This dissertation will discuss the advantages of NPs, the design and construction of a furnace and gas bubbling apparatus for the processing and synthesis of novel NP materials, and property tuning and performance enhancement through synthesis of chalcogenide alloys for photovoltaic and TE materials.




Agrawal, Purdue University.

Subject Area

Chemistry|Chemical engineering|Materials science

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