Chinese Researchers Achieve Record Breaking Thermoelectric Efficiency in Chalcopyrite Materials Through Advanced Lattice Defect Engineering

Chinese scientists use dual antisite defects to achieve record-breaking thermoelectric performance in chalcopyrite, improving efficiency by 59 percent.

By: AXL Media

Published: Apr 30, 2026, 6:12 AM EDT

Source: Information for this report was sourced from EurekAlert!

Breakthrough in Solid State Energy Conversion

A research collective led by Professor Zhang Jian at the Institute of Solid State Physics has announced a significant milestone in the development of high performance thermoelectric materials. By utilizing a sophisticated dual antisite defect strategy, the team achieved a peak figure of merit, or ZT value, of 2.03 at 873 K. This development, published in the Journal of the American Chemical Society, represents a major leap in the effort to convert waste heat into electricity more efficiently, utilizing chalcopyrite based systems as a versatile platform for energy harvesting.

Engineering Atomic Swaps for Better Conductivity

The core of this breakthrough lies in a novel alloying strategy involving silver and indium to introduce specific defects into the crystal lattice of the Cu0.7Ag0.3Ga1-xInxTe2 system. These dual antisite defects occur when specific atoms within the material swap positions, a structural modification that the researchers used to solve a fundamental problem in thermoelectric design. Traditionally, improving a material's electrical conductivity simultaneously increases its thermal conductivity, which is counterproductive for heat conversion. This new strategy allows the material to maintain high electrical efficiency while effectively blocking the flow of heat.

Stabilizing the Material Matrix

To ensure the structural integrity of the material, the researchers optimized the chemical composition to stabilize these atomic defects. The inclusion of silver and indium was found to not only promote the necessary defect formation but also to reduce lattice distortion. This created a uniform solid solution that prevented phase separation, a common failure point in high temperature thermoelectric materials. According to the research findings, these structural adjustments increased the carrier concentration within the material, ensuring that the movement of electrons remained unhindered by the modified lattice.