This Small Business Innovation Research Phase I project will explore the feasibility of fabricating and optimizing a thermoelectric (TE) device suitable for integration into a photovoltaic (PV) cell to increase the performance and lifetime of the PV cell. The TE device can be used to cool and heat the PV cell, effectively increasing the PV efficiency in real-world conditions. The power output of crystalline silicon PV cells decreases 0.4-0.5% for every degree Celsius of increased temperature. In most applications, this leads to a typical loss of about 20% in energy production. Furthermore, the single greatest contributor to the physical end-of-life for any cell is prolonged operation at high temperatures. Therefore, thermal management is an important consideration for any crystalline PV system. TE devices are reversible, have no moving parts, require essentially no maintenance, should last for the lifetime of the PV system and can run directly off the direct current (DC) power generated by the PV array. The ability to manufacture TE inks and optimize TE materials with near-state-of-the-art efficiencies will be demonstrated, and working TE devices will be fabricated to demonstrate their functionality. The broader impact/commercial potential of this project is very significant to the rapidly growing market for PV modules and more important, to the increased efficiency (and decreased emissions) of worldwide energy production. The combination of custom capability, large size, and cost effectiveness will drive a sizeable market for bottom-up TE and TE/PV devices, which can be scaled in capabilities and costs to meet the needs of product developers, as well as volume manufacturers and utilities. Advantages of the controlled ink-jet printing method of manufacturing thermoelectric elements over conventional methods include: ability to control the physical properties of the materials during the fabrication, capability to achieve high compaction density of the 3-D structure using nanoparticles, reduced costs, and reduced fabrication times. The proposed effort will increase the body of knowledge and advance technology in the areas of solid-state physics and chemistry, ink chemistry, microfluidics, inkjet print deposition, and inkjet printer design. The results of this effort will also greatly increase knowledge of long-term cell degradation processes in PV systems, thereby improving reliability and economics of this very large component of future energy supply.
