Optical properties of SnCl2 phosphor

A white SnCl2 phosphor is synthesized by the chemical etching of Sn shots in an aqueous HCl solution. The optical properties of this phosphor are investigated using diffuse reflectance, photoluminescence (PL) analysis, PL excitation spectroscopy, and PL lifetime measurements. The SnCl2 phosphor exhibits PL in the blue (∼460 nm) and red spectral regions (∼600 nm) under ultraviolet excitation (≥4.1 eV). The differences in the PL features observed using Nd:YAG (λ = 266 nm) and He-Cd (λ = 325 nm) lasers as excitation light sources are interpreted using the configurational-coordinate model, taking into account the band-gap energy (∼3.8 eV) of SnCl2 and the excited-state energies of the Sn2+ ions. A reliable energy level diagram for Sn2+ ions in the SnCl2 host is also proposed.