LiTaO3 nanoparticles for infrared detectors

Lithium tantalate (LiTaO3) is a multifunctional pyroelectric, piezoelectric and photoelectric material used in infrared sensors, non-linear optics, surface acoustic wave devices, etc. Although lithium tantalate is well known and widely used, the nanosized particles are difficult to obtain due to agglomeration and crystalline size increase during traditional synthesis methods via calcination in furnaces at high temperatures of over 800 C. In this work, LiTaO3 nanoparticles were synthesized using wet chemical approach. Initially, the micrometer sized tantalum pentoxide was transformed to nano-sized particles by dissolving it in 48% HF at 80 C for 8 hours, then precipitated with 30% ammonium hydroxide, washed with deionized water and dried at 200 C for 6 hours. The nanosized tantalum oxide was mixed with stoichiometric amount of lithium hydroxide in high energy ball mill in acetone media, dried and calcinated at 650 C for 4 hours. This temperature was chosen based on thermogravimetric analysis. The surface morphology was examined via scanning electron microscope (SEM) showing particles below 100 nm size, Fourier Transform Infrared Spectroscopy (FTIR) showed absorption in 16.9-18.3 micrometer range, and XRD analysis confirmed LiTaO3 phase without impurities.