Process for synthesizing europium-doped strontium magnesium germanate phosphors

A process for synthesizing europium-doped Sr2MgGe2O7 phosphors, the process comprising:

• preparing an aloe vera (A.V.) gel extract upon treating fresh aloe vera stems;
• (b) dissolving Sr(NO3)2, Mg(NO3)2, Ge(NO3)4, and Eu(NO3)3 corresponding to Eu3+ doping levels of 0-6 mol % in distilled water to form a homogenous solution;
• adding Aloe Vera (A.V.) gel extract as both fuel and templating agent to the solution;
• stirring the mixture at room temperature for 30 minutes using a magnetic stirrer to form a viscous gel-like solution;
• transferring the viscous gel-like solution in a borosilicate beaker and heating in a muffle furnace at 500° C. to initiate an exothermic combustion reaction producing a porous spongy mass;
• calcining the porous spongy mass at 800° C. for 4 hours;
• and
• cooling the material at room temperature and collecting thereby grinding using an agate mortar and pestle to obtain the europium-doped Sr2MgGe2O7 (SMGO:x % Eu3+ (x=0-6 mol %)) phosphors, wherein the SrMgGeO4:x % Eu3+ (x=0-6 mol %) phosphors is prepared via a green solution combustion technique, repeated for each Eu3+ concentration from 0 to 6 mol %;
• wherein preparing the Sr2MgGe2O7:x % Eu3+ phosphors via the green solution combustion technique comprises preparing a separate precursor batch for each europium concentration by dissolving individually weighed quantities of the metal nitrates in preheated distilled water, adjusting the total oxidizer content by calculating oxygen equivalence from the nitrate ions, adding a measured amount of Aloe vera gel to each batch to establish a fuel-to-oxidizer ratio suitable for self-propagating combustion, stirring each batch until a uniform viscous gel is obtained, and transferring each viscous gel to a designated combustion vessel so that each europium concentration undergoes an independent combustion cycle, and wherein the green solution combustion technique for each europium concentration further comprises heating each viscous gel in a furnace that has been stabilized at a pre-dehydration temperature between 250° C. and 300° C. to remove entrapped moisture, subsequently elevating the furnace temperature to 500° C. to initiate auto-ignition of the gel matrix, permitting the combustion to propagate across the full gel mass through internally generated gases, holding each batch inside the furnace for a settling period after flame extinction to allow post-combustion intermediate phases to consolidate, and collecting the porous spongy mass corresponding to each europium concentration in a separately labeled container, and
• wherein the green solution combustion technique for each europium concentration additionally comprises crushing the porous spongy mass obtained from each combustion run, pre-drying each crushed mass at 120-150° C. to eliminate residual volatiles, loading each dried mass into a separate ceramic crucible, calcining each crucible at 800° C. for four hours while maintaining a controlled temperature ramp of 3-5° C. per minute, cooling each crucible naturally to room temperature inside the furnace chamber without forced convection, and subsequently grinding, sieving, and desiccating each calcined phosphor batch independently so that no cross-contamination occurs between different europium doping levels.