High-Quantum-Yield [Eu(Phen) 2 (NO 3 ) 3 ] Phosphor Exhibiting Zero Thermal Quenching under Real Operating Conditions (30–150 °C)

High Resolution Image Download MS PowerPoint Slide In this study, we present the first investigation of the temperature-dependent luminescence properties of the [Eu(Phen) 2 (NO 3 ) 3 ] complex across the 30–150 °C range. The coordination environment, thermal stability, and structural analysis of the complex were studied by Fourier-transform infrared spectroscopy, thermogravimetric analysis, and powder X-ray diffraction techniques. Photoluminescence studies under excitation at 350 and 396 nm revealed the characteristic Eu 3+ emission arising from the 5 D 0 → 7 F J ( J = 1–4) transitions. Additionally, the complex exhibits a long luminescence lifetime (τ = 1.096 ± 0.001 ms) and a high photoluminescence quantum yield (Φ = 96%) with λ exc = 350 nm. The photometric analysis confirms deep-red emission with 99% color purity and CIE 1931 chromaticity coordinates ( x, y ) = (0.66, 0.33). Notably, the [Eu(Phen) 2 (NO 3 ) 3 ] complex exhibits zero thermal quenching over the temperature range, which could be attributed to the effective suppression of thermally activated back-energy transfer. These results demonstrate exceptional thermal robustness, highlighting its potential for thermally stable red-emitting optical applications.