Eco‐friendly and high‐performance thermoelectric materials that interconvert heat and electricity based on the Seebeck effect and Peltier effect are urgently needed due to their enormous potential in so

Eco‐friendly and high‐performance thermoelectric materials that interconvert heat and electricity based on the Seebeck effect and Peltier effect are urgently needed due to their enormous potential in solid‐state power generation and refrigeration. Recently, revolutionary advances driven by experiments are made in developing innovative organic thermoelectric materials. Meantime, with the help of state‐of‐the‐art first‐principles calculations, theoretical understanding and rational design of organic thermoelectric materials are emerging. This review presents the authors' current progress achieved in design strategies for high‐performance organic thermoelectric materials at the level of atomistic simulation. The in‐depth understanding gained in these explorations will help to build the fundamental structure–property relationship, and in turn promote the development of next‐generation high‐performance organic thermoelectric materials.

One of the most burning problems in organic thermoelectrics is the lack of deep understanding on the key limiting factors of thermoelectric efficiency at different length scales for conducting

One of the most burning problems in organic thermoelectrics is the lack of deep understanding on the key limiting factors of thermoelectric efficiency at different length scales for conducting polymers. Here, by examining a prototypical π ‐conjugated polymer, poly(3‐hexylthiophene) from molecular level to crystalline and polycrystalline domains, and on the basis of first‐principles calculations, new insights are presented into the thermoelectric transport in conducting polymers, and new material design guidelines are provided. It is proved that in the crystalline domains of conducting polymers, due to the strong electrostatic interactions between free charge carriers and counterions, the power factor within a wide range of doping level is governed by the counterion‐induced electronic scattering. It is corroborated that in the polycrystalline domains, although the short mean free path prevents the holes undergoing grain‐boundary scatterings, the crystallite orientations relative to the conduction path and the grain sizes strongly affect the power factor, leading to the modulation of the power factor by at least two orders of magnitude.