Investigating the Ligand Exchange in CuFeS₂ QDs for Thermophotovoltaic Application

Transition metal chalcogenide nanomaterials, offer promising alternatives to traditional, environmentally harmful materials due to their tunable optical and electronic properties, low toxicity, and abundance. The narrow bandgaps, size-dependent quantum confinement effects, and broad absorption of these nanomaterials make them particularly suitable for a variety of applications including photovoltaics,[1] energy storage[2][3] and catalysis.[4]
Thermophotovoltaic (TPV)[5] technology which convert thermal radiation into electrical energy has recently gained significant attention as an innovative solution for harvesting waste heat.
CuFeS₂ quantum dots (QDs),[6][7] with its low bandgap and broad absorption characteristics can capture infrared radiation effectively and is particularly interesting for TPV application. Moreover, their abundance and low toxicity make CuFeS₂ an environmentally sustainable alternative to traditional semiconducting materials.
However, the practical application of CuFeS₂ QDs in TPV and other energy conversion systems is limited by the surface chemistry of the QDs. Native surface ligands, which are introduced during the synthesis of QDs, often act as insulating barriers that inhibit charge carrier transportation.[8] This limitation not only affects the efficiency of charge transport within the material but also complicates the integration of QDs into device architectures, particularly in systems that demand high thermal and chemical stability.
This work focuses on optimizing ligand exchange processes on the surface of CuFeS₂ QDs to improve their optoelectronic properties, stability, and processability for device integration. The study investigates the replacement of native ligands, which are typically long-chain organic molecules, with more conductive and stable alternatives such as thiol-based and halide ligands. The goal is to enhance the electronic coupling between QDs, reduce insulating effects, and increase charge carrier mobility-critical factors in maximizing the device efficiency.



References:
[1] K. Nassiri Nazif, et al., Nat. Commun. 2021, 12, 7034

[2] H. Shuai, et al., Adv. Energy Mater. 2023, 13, 2202992;

[3] J. Rehman et al., ACS Appl. Energy Mater. 2022, 5, 6481;

[4] Y. Guo, et al., Adv. Mater. 2019, 31, 1807134;

[5] Johansson, E.M.J. and Andruszkiewicz, A. Energy Technol., 2022 10: 2200598

[6] Ghosh S, et al., Chemistry of Materials 2016 28 (13), 4848-4858

[7] B. Bhattacharyya, et al. Adv. Optical Mater. 2023, 11, 2202411

[8] Patrick R. Browne et al., ACS Nano 2014, 8, 6, 5863–5872