A new diphosphate Li2Na2P2O7: Synthesis, crystal structure, electronic structure and luminescent properties.

Abstract For the first time, a mixed-alkali diphosphate, Li 2 Na 2 P 2 O 7 , has been successfully obtained by high-temperature solution growth (HTSG) method. Single crystal X-ray diffraction analysis reveals that it contains anionic [Li 2 P 2 O 7 ] ∞ network and 1D [Na] ∞ infinite chains, which are both running along the c -axis. Band structure calculations by density functional theory (DFT) method indicate that Li 2 Na 2 P 2 O 7 has an indirect band gap of about 4.88 eV. Moreover, 1 mol% Eu3+ doped Li 2 Na 2 P 2 O 7 phosphor was synthesized and its photoluminescence properties were investigated. Under near ultraviolet (NUV) excitation (394 nm), Li 2 Na 2 P 2 O 7 :0.01Eu3+ phosphor exhibits a series of emission peaks corresponding to the 5D 0 →7F J (J = 0, 1, 2, 3, 4) transitions of Eu3+ ion with the CIE chromaticity coordinates of (0.599, 0.375). Graphical abstract This paper affords a novel lithium sodium diphosphate Li 2 Na 2 P 2 O 7 via high temperature flux method. The wide band gap of about 4.88 eV makes it suitable to be used as a luminescent host matrix. It can emit intense red light after doping with Eu3+ ions. fx1 Highlights • This work provides a novel lithium sodium diphosphate, Li 2 Na 2 P 2 O 7. • Li 2 Na 2 P 2 O 7 has an indirect bond gap of about 4.88 eV. • 1 mol% Eu3+ activated phosphor was synthesized by a solid-state reaction and its photoluminescence properties were studied. • Under 394 nm light excitation, Li 2 Na 2 P 2 O 7 :0.01Eu3+ exhibits a series of bonds corresponding to the 5D 0 →7F J (J = 0, 1, 2, 3, 4) of Eu3+ ion. [ABSTRACT FROM AUTHOR]