Fe:Co:ZnSe nanocrystals with different co-doping ratios of Fe2+/Co2+ ions were fabricated by hydrothermal synthesis.
These nanocrystals are spherical in shape and exhibit a cubic sphalerite structure with an average grain size of about 15 nm. Through the energy conversion between Co2+ and Fe2+ ions, mid-infrared fluorescences at 3.3 μm and 4.4 μm were detected under 1550 nm laser excitation at room temperature.
The facile method used in the present work from a research team led by Prof. Dr. GUO Haitao from Xi'an Institute of Optics and Precision Mechanics (XIOPM) of the Chinese Academy of Sciences (CAS) avoids the mid-infrared quench effect induced by the organic molecular introduced in the past preparation process.
The fluorescence band of 4.4 μm in the Fe:Co:ZnSe nanocrystals is thought to be an overlapping emission involving the peak centered at 4648 nm corresponding to the Co2+ : 4T1(F) → 4T2 (F) energy transition and the peak centered at 4273 nm corresponding to Fe2+ : 5T2(D) → 5E (D) energy transition.
These high-quality optically active nanomaterials show potential applications in mid-infrared devices such as composite fiber-amplifiers and lasers materials.
FE-TEM、HRTEM 、EDS spectra and the element distribution of 0.6 mol % Fe 3 mol % Co: ZnSe nanocrystals. (Image by XIOPM)
(Original research article “Journal of Luminescence”(2020) http://dx.doi.org/10.1016/j.jlumin.2020.117102 )
