In the quest to meet the escalating energy demand and keep in line with environmental regulations electronic organic materials have emerged to complement alternative and green energy sources. A research initiative led by KAUST has developed electron-transporting organic semiconductors. Termed as n-type, these semiconductors could help produce electricity from waste heat discharged from industries and homes.
In fact, thermoelectric generators that can transform changes in temperature or gradients into electricity are highly suitable for harnessing waste heat. Characteristically, thermoelectric generators are readily scalable and are environment friendly sans moving parts, which makes them resistant to wear. Interestingly, thermoelectric generators work in two ways that has direct correlation with their efficiency to convert energy: they maximize the electrical conductivity and Seebeck coefficient of constituent pieces –
Structurally, at the core, thermoelectric generators are composed of two electronically different materials, viz., n-type semiconductor and hole-transporting semiconductor, which are joined to each other at the ends to form a circuit. For this reason, the efficiency of conversion of thermoelectric generators depends on optimal performance of both the constituent semiconductors.
Meanwhile, recently, organic thermoelectric materials have emerged as easier to process and less toxic than their cheaper and abundantly available counterparts. Importantly, whilst the thermal conductivity of the new materials remains lower, their thermoelectric performance remains insufficient. Typically, weakened n-type semiconductors are unstable in ambient conditions and display lower electrical conductivity than their p-type counterparts, which are widely examined.
“Nonetheless, to find n-type organic materials that are comparable in performance to the best p-type semiconductors remains a challenge, stated the lead researcher of the study.
In a bid for this, the KAUST team developed a systematic approach to synthesize doped n-type organic semiconductors that are stable in air, and feature high thermoelectric performance.