Seeking new, highly effective thermoelectrics

Operating across a wide temperature range is a priority for thermoelectric materials Thermoelectric technology can directly and reversibly convert heat to electrical energy. Although thermoelectric energy conversion will never be as efficient as a steam engine ( 1 ), improving thermoelectric performance can potentially make a technology commercially competitive. Thermoelectric conversion efficiency is estimated by the so-called dimensionless figure of merit, ZT = S 2 σ T /κ, where S , σ, T , and κ denote the Seebeck coefficient, electrical conductivity, working temperature, and thermal conductivity, respectfully . These parameters are strongly coupled, and improving the final ZT is challenging as a result. Strategies for boosting thermoelectric performance include nanostructuring, band engineering, nanomagnetic compositing, high-throughput screening, and others ( 2 ). Many of these strategies create a high ZT in a narrow range of temperatures, limiting the overall energy conversion. Finding materials with wider operating temperature ranges may require rethinking development strategies.