Achieving Luminescence of Sr3Ga1.98In0.02Ge4O14:0.03Cr3+ via [In3+] Substitution [Ga3+] and Its Application to NIR pc-LED in Non-Destructive Testing

Cr3+-doped Sr3Ga2Ge4O14:0.03Cr3+(SGGO:0.03Cr3+) phosphor was synthesized via a high-temperature solid-phase method. Considering the tunable structure of SGGO, Ga3+ions in the matrix were substituted with In3+ions at a certain concentration. The tuned phosphor produced a red-shifted emission spectrum, with its luminescence intensity at 423 K maintained at 63% of that at room temperature; moreover, the internal quantum efficiency increased to 65.60%, and the external quantum efficiency correspondingly increased to 21.94%. On this basis, SGIGO:0.03Cr3+was encapsulated into apc-LED, which was applied in non-destructive testing (NDT) experiments, successfully realizing the recognition of water and anhydrous ethanol, proving its potential application in the field of NDT.