Electronic organic materials are capable enough to support alternative and green energy sources as a solution against augmenting global energy demands and severe environmental regulations. Recently, Organic thermoelectric materials are being thought of as the best for ecology. This is because they are easy to process, cheap, less toxic, and, most importantly, present in abundance as compared to conventional inorganic counterparts. The new materials also have lower thermal conductivity; however, their thermoelectric performance is inadequate. Generally, doped n-type organic semiconductors are not considered to be stable in ambient conditions. The reason being that they display lower electrical conductivities than their p-type equivalents, which have been the core subject of many studies.
Finally, researchers have succeeded in developing electron-transporting. A systematic approach has been devised which fuses high thermoelectric performance into the air-stable doped n-type organic semiconductors. This is a huge development in Organic Semiconductor Market as these types of semiconductors could very well generate electricity from waste heat produced by several industries and homes.
Thermoelectric generators are the best available option for exploiting waste heat as they can convert temperature changes or gradients into electricity. The devices are not only scalable but also extremely environmentally friendly. Interestingly, they do not have any moving parts, resulting in better resistance to wear and tear. Their efficiency is based on their ability to minimize the thermal conductivity and to maximize the electrical conductivity of their components.
The new generators are based on two materials that are completely different electronically, named as hole-transporting (or p-type) semiconductor and an n-type semiconductor. Both these materials are joined at their respective ends so that a circuit can be formed. Hence, the generators' efficiency in converting depends largely upon optimal performance being given by these two types of materials.
The monomers in the generator consist of cyclic lactams or amide, amalgamated with naphthalene and anthracene cores. In turn, they are generating rigid conjugated polymers with the help of nontoxic metal-free acid-catalyzed polymerization. Researchers have revealed that no rotational freedom is present along the backbone. As a consequence, the energetic disorder is reduced, and electrical conductivity is subsequently enhanced.
This novel design has electrons withdrawing lactam groups that give an output of a highly electron-deficient backbone, resulting in stabilizing the polymer under ambient conditions. Furthermore, small cores paved the way for bigger electron affinity and improved thermoelectric performance in the polymers. This is the first time something has been demonstrated physically.
The team is optimistic that their air-stable polymers have good commercial potential. In the future, they plan to make scalable processes so that these materials can be integrated into thermoelectric generators.