Development of Cu₂NiSnSe₄ Nanocrystals: Effects of Annealing on Structural and Electrical Properties

¹ Centre of Excellence for Energy Research, Sathyabama Institute of Science and Technology, Chennai, India.
² School of Engineering and Technology, Jaipur National University, Jagatpura, Jaipur - 302017, Rajasthan, India.
³ Centre for Nanoscience and Nanotechnology, Sathyabama Institute of Science and Technology, Chennai, India.
⁴ UGC-DAE-CSR Kalpakkam Node, Kokilamedu, Tamilnadu, India

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Published online: 10 March 2026

Abstract

This work investigates structural, electrochemical, and electrical enhancement of Cu₂NiSnSe₄ (CNTSe) synthesized by high-energy ball milling followed by post-annealing at 450°C. X-ray diffraction confirmed the formation of a tetragonal kesterite structure in both as-synthesised and annealed CNTSe with the annealed samples exhibiting markedly improved crystallinity and grain uniformity. FESEM results indicate that annealing leads to more uniform elemental distribution and promotes the development of well-defined grains. Hall measurements and electrochemical demonstrated superior electrical properties, including a high Specific capacitance of 1380.93 F/g and Electrical conductivity of 6.08 × 10³ (mho. cm) and a narrow band gap of 1.1 eV suitable for harvesting solar energy. These finding highlights the crucial role of annealing in optimizing CNTSe for solar cell and supercapacitor applications. Moreover, the mechanochemical synthesis route provides a simple, scalable, eco-friendly method of developing semiconducting materials for advanced energy technologies.