Architecture of ytterbium selenite nanorods: unlocking structural, optical, magnetic and electrochemical behaviour with boosting performance for supercapacitors

Abstract

Ytterbium selenite (Yb₂Se₃O₉) was successfully synthesized using a simple coprecipitation technique, resulting in bamboo-like nanorods approximately 110 nm in size. The compound crystallizes in a monoclinic structure and exhibits promising features for optoelectronic applications and UV filtering. Spectroscopic analysis reveals native point defects as well as Schottky and Frankel surface defects, which facilitate radiative electron–hole recombination making it a potential material for display technologies. Ytterbium is embedded within an oxide matrix in the sample, and a distinct magnetic phase transition occurs between 20 K and 30 K under an applied magnetic field. At room temperature 300 K, the M–H curve indicates weak ferromagnetic behaviour. Electrochemical evaluation of Yb₂Se₃O₉ based electrodes in both symmetric and asymmetric supercapacitor configurations revealed impressive performance. The symmetric device exhibited a specific capacitance of 142.51 F g⁻¹, an energy density of 11.98 W h kg⁻¹, and a power density of 550 W kg⁻¹ at 1 A g⁻¹, with 78.09% capacitance retention after 10 000 cycles. Remarkably, the asymmetric supercapacitor achieved a higher specific capacitance of 169.86 F g⁻¹, an energy density of 60.39 W h kg⁻¹, and a power density of 800 W kg⁻¹ within a 1.60 V potential window, retaining 85% of its capacitance after 10 000 cycles. Impedance spectroscopy confirmed the material's double-layer capacitive behaviour. Overall, the asymmetric configuration demonstrated superior performance, making Yb₂Se₃O₉ a promising candidate for energy storage and conversion technologies.