Optical properties of lead-free Cs$_2$AgInCl$_6$ : Bi/SiO$_2$ nanocrystals with double perovskite crystal structure

The optical characteristics of lead-free nanocrystals with a crystal structure of the double perovskite type with the chemical composition Cs$_2$AgInCl$_6$, doped with bismuth and coated with silicon dioxide were studied, and the possibility of their further application was shown. The optical properties of the nanocrystals under study are analyzed by absorption and luminescence spectroscopy, including those with time resolution. Images were obtained using a scanning electron microscope. The influence of the amount of silicon dioxide precursor addition on the optical properties and morphology of lead-free nanocrystals was established. It is shown that the observed broad photoluminescence band is associated with the occurrence of self-trapped excitons in such nanocrystals. To demonstrate the possibility of practical application of these nanocrystals a light-emitting device based on them was developed and constructed. The light emitting device has a wide emission spectrum close to warm white light.