Copper Iron Chalcogenide Semiconductor Nanocrystals in Energy and Optoelectronics Applications—State of the Art, Challenges, and Future Potential

Abstract I‐III‐VI 2 semiconductor nanocrystals have been explored in countless optoelectronics and green energy applications. While indium‐based compounds are arguably the best‐known variants of these semiconductors and have been widely studied for their photophysical properties, other I‐III‐VI 2 semiconductors are emerging as serious competitors. This review focuses on the current state of the art and recent progress made in the research and technology of one of the most promising competitors to indium‐based I‐III‐VI 2 semiconductor nanocrystals, CuFeS 2 nanocrystals. CuFeS 2 is a promising alternative to indium‐based systems, mostly because many properties are competitive and because iron is much more abundant than indium. Replacing In(III) with Fe(III) would thus significantly alleviate the issue of raw material availability. The article highlights new synthesis approaches and summarizes and discusses advanced optical properties including surface plasmon resonance and luminescence properties. Moreover, potential applications in thermoelectric, photodetection, photothermal, and photovoltaics are illustrated and discussed. Finally, future perspectives for materials development, upscaling, and application in new processes and devices, such as self‐assembly, patterning, or plasmonic catalysis, are presented as well.