A team led by UMass chemist Dhandapani Venkataraman, “DV,” and electrical engineer Zlatan Aksamija, reported in Nature Communications on an advance they outline toward more efficient, cheaper, polymer-based harvest of heat energy. “It will be a surprise to the field,” DV predicts, “it gives us another key variable we can alter to improve the thermo-electric efficiency of polymers. This should make us, and others, look at polymer thermo-electrics in a new light.” Aksamija explains, “Using polymers to convert thermal energy to electricity by harvesting waste heat has seen an uptick in interest in recent years. Waste heat represents both a problem but also a resource; the more heat your process wastes, the less efficient it is.”

DV and his chemistry PhD student Connor Boyle, with Aksamija and his electrical engineering Ph.D. student Meenakshi Upadhyaya worked in what DV calls “a true collaboration,” where each insight from numerical simulations informed the next series of experiments, and vice versa. The team turned to chemist Michael Barnes, a co-author on their recent paper, who used Kelvin Probe Force Microscopy to probe the dopants at the nano level and show that clustering is indeed present in polymers doped at room temperature, but not at higher temperatures.

The findings should provide a new path for designing more efficient polymers for thermo-electric devices. DV notes that until now, chemists and materials scientists have been trying to organize polymers to be more like the inorganics, “nicely aligned and very regular, which is difficult to do,” he adds. “It turns out that this may not be the way to go; you can take another road or another approach. We hope this paper provides a basis to move polymer-based thermo-electrics forward.”