Synthesis and NIR Emission in Rankinite Ca₃Si₂O₇:Nd³⁺ Phosphor for Optical Applications

Near infrared (NIR) emitting, Nd³⁺-doped Rankinite type Ca₃Si₂O₇ silicate phosphors were synthesized using solid-state reaction method. Morphology, crystal structure and optoelectronic properties of the proposed silicate were analysed using SEM, XRD and photoluminescence, respectively. XRD confirms the Rankinite type monoclinic structure having a space group of P21/a (No.14). SEM, EDS and elemental mapping studies approve the surface properties and elemental composition. The photoluminescence (PL) emission observed in NIR region upon Nd³⁺ doping at 1065 nm attributed to ⁴F_3/2 → ⁴I_11/2 under the fixed excitation of 589 nm (⁴I_9/2 → ⁴G_7/2). The concentration quenching is recorded at 1.0 mol% of Nd³⁺ ions. The critical distance (Rc) is 31.39 Å, which surpasses the ideal range ~5 Å, typical of exchange interactions. Van Uitert confirmed the transfer of energy between nearest neighbouring ions, which contributes to the concentration quenching. The obtained results suggest it as a potential optical material for optoelectronic devices.