A new family of self-activated phosphors

Abstract

A series of compounds were discovered which have the generalized formula R₂²⁺R⁴⁺R₂⁵⁺O₉. Examination of single crystals of Pb₂ZrP₂O₉ showed it to have hexagonal symmetry with α_H = 10.08Å and c_H = 23.29Å. Five of the seven compounds studied (Ba₂ZrP₂O₉, Sr₂ZrP₂O₉, Pb₂TiP₂O₉, Ba₂ZrAs₂O₉, and Pb₂ZrAs₂O₉) were isostructural with Pb₂ZrP₂O₉, and the seventh, Sr₂ZrAs₂O₉, had optical properties closely related to the group. With the exception of Pb₂TiP₂O₉, all of the compounds exhibited a broad band blue fluorescence, with an intensity maximum near 4800Å, when excited by 2537Å radiation. By contrast, Pb₂TiP₂O₉ showed a weak orange fluorescence, more easily excited by 3650Å radiation. Emission, absorption, and excitation data are presented.