Self-Trapped Exciton Photoluminescence from Polycrystalline K 2 AgI 3 Obtained by Solid-State Reaction Method

Polycrystalline K2AgI3 is synthesized by solid-state reaction at 403K using AgI and KI as starting materials. X-ray diffraction, photoluminescence (PL) spectra, photoluminescence excitation (PLE) spectra, electron paramagnetic resonance (EPR) and absorption spectra are employed to investigate the structure and photo-physical properties of such material. A broad luminescence band centered at about 608nm at 180K with large Stokes shift is found. When the temperature rises to about 300K, an obvious PL blue-shift, PL intersity weakening, and an emission band broadening are observed. It is suggested that the emission at about 608nm may originate from the recombination of self-trapped excitons.