Sr2Zn3Te2P2O14 as a Host for New Colored Compounds and Tunable White Light Emission

Abstract The compound, Sr 2 Zn 3 Te 2 P 2 O 14 , was explored as a host to prepare new, brightly colored compounds and rare‐earth ions based white light emission. All the compounds were synthesized at 750–880°C in air and characterized. The structure has Zn 2+ ions in both tetrahedral as well as distorted square planar coordination. The substitution of transition elements such as Co 2+ , Ni 2+ , and Cu 2+ ions in place of Zn 2+ ions results in compounds exhibiting bright colors under daylight. The studies indicated that the Cu 2+ ions prefer square–planar geometry, which was supported by UV–visible, EPR, and Raman spectroscopic studies. The substitution of P 5+ ions by V 5+ ions along with transition elements in place of Zn 2+ ions results in compounds with different colors. The change in color is due to the metal‐to‐metal charge transfer (MMCT) transitions involving partially filled 3d n electrons of the transition elements and empty 3d 0 orbitals of V 5+ ions. The near‐IR reflectivity studies indicate that the white‐colored compounds exhibit good near‐IR reflectivity behavior, that are comparable to TiO 2 . The substitution of rare‐earth ions, namely, Eu 3+ , Tb 3+ , and Tm 3+ ions in place of 8‐coordinated Sr 2+ ions results in characteristic emissions in the red, green, and blue regions, respectively. A careful manipulation of the concentration of these three ions (Eu 3+ , Tb 3+ , and Tm 3+ ) resulted in white light emission for the composition Sr 2 Zn 3 Te 2 P 2 O 14 : 1%Tm, 2% Tb, and 3% Eu. Based on the lifetime measurements, a possible schematic of the energy transfer pathway has also been proposed. The white‐colored compounds exhibited reasonable dielectric constant values with low dielectric loss. Magnetic studies indicate anti‐ferromagnetic interactions. The present study suggests that the telluro‐phosphate compounds could be good candidates to explore many different physical and chemical properties.