Low temperature synthesis of multilayered-hollow microspheres of boron carbide from castor oil for photonic applications

Abstract

The development of boron carbide microspheres of various types is of greater interest because of their applications in thermal insulation, imaging, luminescent coating, and drug delivery. The present methods of synthesis involve costlier equipment, toxic chemicals, and high temperature. This work describes low temperature, green synthesis of multilayered-hollow microspheres of boron carbide using the natural carbon precursor—castor oil. Refluxion of boric acid with castor oil and successive cooling results in the formation of boron carbide and is subjected to thermal deposition at 300 °C for 1 h to get a thin film. The field emission scanning electron microscopic analysis shows the formation of multilayered hollow microspheres in the film whose surface morphology is studied using an atomic force microscope. The X-ray diffraction, X-ray mapping, and energy dispersive spectroscopic and Fourier transform infrared spectroscopic analyses confirm the formation of boron carbide which is thermally stable and gives a yield of 37% at 800 °C. The optical characterization of the sample is carried out with ultraviolet-visible and photoluminescence spectroscopic techniques. The chromaticity diagram and the power spectrum suggest the possible use of the material as a blue light emitter.