Fluorescence properties with red-shift of Eu2+ emission in novel phosphor-silicate apatite Sr3LaNa(PO4)2SiO4 phosphors

Multi-wavelength excited white-emitting K2Gd(1−x)(PO4)(WO4):xDy3+ phosphors with satisfactory thermal properties for UV-LEDs

“…In general, the non-radiative energy transfer among Dy 3+ ions causing the concentration quenching is dominant, following three types of mechanisms: radiation reabsorption, exchange interaction, or a multipolar-multipole interaction. 24 In order to identify the mechanism of energy transfer, the critical distance (R C ) between the activated ions for energy transfer can be evaluated according to the equation given by Blasse: 25…”

Synthesis, luminescence and energy transfer of Ca3GdNa(PO4)3F: Ce3+, Tb3+ phosphor with novel apatite structure

“…We can achieve the radius of each cation in different coordination environments [9] from table 1. Considering the difference of valence state and radius of each cation, the substitution of two Ca 2+ by Gd 3+ and Na + had occurred [10]. Matrix crystal Ca 3 GdNa(PO 4 ) 3 F was obtained after being replaced by Gd 3+ and Na + .…”

Investigation of Physicochemical Properties of the Structurally Modified Nanosized Silicate-Substituted Hydroxyapatite Co-Doped with Eu3+ and Sr2+ Ions

“…The m anism could be described as follows (Equation (2)): 3+ ions first replace into the Ca(1) site and this preference changes with incre Eu 3+ concentration in favor of the Ca(2) site. In case of substitution into the Ca (2) where calcium(II) ions are surrounded with one hydroxyl group and six oxygen a from PO4 3− , these hydroxyl groups could participate in the charge compensation m nism, expressed as (Equation (3)):…”

“…Moreover, this is possible only in the low-symmetry crystal position as in C n , C nv as well as C S symmetry. In the hydroxyapatite matrix, calcium ions are located at two different crystal positions: Ca(1) and Ca (2) with local symmetry at C 3 and C S , respectively. Both calcium positions could be occupied by Eu 3+ ions.…”

“…Moreover, two unequal calcium positions can be substituted by ions with +1, +2 or +3 charges, such as Sr 2+ , Ba 2+ , K + , Na + , Mn 2+ , Li + , Mg 2+ as well as lanthanide ions, etc. [1][2][3].…”