Construction of single-crystal nanoparticles assembled CuFe2O4 spinel microspheres towards high infrared emissivity

Recently, spinel-based materials have attracted tremendous interest in high infrared radiation regimes owing to their unique crystal structure. Nevertheless, to date, it still remains a formidable challenge to efficiently design and synthesize spinel materials with excellent infrared radiation properties at lower temperatures, especially for the tetragonal CuFe2O4 spinel. Herein, a simple two-step strategy (i.e., solvent-thermal treatment and subsequent calcination) was developed to fabricate single-crystalline nanoparticles assembled tetragonal CuFe2O4 microspheres (MSs) at a low sintering temperature of 800 °C (denoted as CFO-800). Thanks to the synergy of intrinsic factors including the single crystal properties and moderate CuO impurity as well as the unique spherical structure, the resultant CFO-800 specimen is endowed with enhanced infrared absorption. Consequently, the emissivity values are achieved as high as 0.514 at room temperature and even 0.972 at a test temperature of 800 °C in the wavelength range of 3 – 5 µm. More importantly, this research provides valuable insights into the rational design and construction of single-crystalline spinel materials with enhanced infrared radiation performance.