Investigation on morphology and broadband blue-white emission modification of La1–xBixOCl polycrystals

Tetragonal structure La1–xBixOCl polycrystals were prepared by solid state synthesis. With increase in bismuth content, the morphology of the prepared samples changed from non-oriented particles to layered crystals and the broadband blue-white emission from LaOCl polycrystals decreased dramatically. Comparative experiments and X-ray photoelectron spectroscopy（XPS） analysis indicated that the host emission more possibly originated from Cl self-doping in oxychloride crystals. According to a close composition relationship of the Cl self-doping behavior and crystal morphology, it was suggested that the La composition strengthened the interlayer interaction between Cl– anion and crystal cell lamellar, hindering the orientation of LaOCl crystals. The results of our work would deepen the understanding of the orientation structure of tetragonal oxyhalides and offer an insight into the origin of its host luminescence.