Metal silicate-silica-based polymorphous phosphors and lighting devices

A phosphor according to the formula:

• [(BvSiO3)x(Mv2SiO3)y(Tv2(SiO3)3)z]m.(SiO2)n:Rε, X (I)
• wherein x, y and z are any value such that x+y+z=1;
• By is one or more divalent alkaline earth metals;
• Mv is one or more monovalent alkaline metals;
• Tv is one or more trivalent metal ions;
• Rε is one or more activators selected from Eu2+ and Mn2+;
• X is one or more halides;
• m is 1 or 0;
• and (i) n>3 if m=1 and provides an amount of silica effective to host useful luminescence or (ii) n=1 if m=0.

A method of making a phosphor according to the formula:

• [(BvSiO3)x(Mv2SiO3)y(Tv2(SiO3)3)z]m.(SiO2)n:Rε, X (I)
• wherein x, y and z are any value such that x+y+z=1;
• By is one or more divalent alkaline earth metals;
• Mv is one or more monovalent alkaline metals;
• Tv is one or more trivalent metal ions;
• Rε is one or more activators selected from Eu2+ and Mn2+;
• X is one or more halides;
• m is 1 or 0;
• and (i) n>3 if m=1 and provides an amount of silica effective to host useful luminescence or (ii) n=1 if m=0,
• comprising:
• providing an appropriate mixture of precursors optionally including a halide source;
• and
• firing the product of the first heating at a temperature from 900° C. to 1300° C. under a reducing atmosphere and in the presence of a halide source,
• wherein one or more of the following applies:
• the process further comprises, prior to the firing, heating the appropriate mixture, optionally including a halide source, at a temperature from 700° C. to 1100° C. under a reducing atmosphere, where the heating is at a temperature lower than that of the firing, or
• the mole percentage of X in the phosphor product is 5% or less of SiO2.