Robust thermal performance and color purity of samarium based deep red emitting phosphor for near-UV chip-based high-color-rendering

Abstract

In the progress of LED phosphors, the chemical stability, thermal stability, and color purity was not usually given due attention. However, the most critical problems of WLEDs are the deficit in the red-spectral region, stability, low color-rendering index (CRI) and high correlated color temperature (CCT) limit its efficiency for vivid application. Herein, the Ca3YGa3B4O15:xSm3+ (CYGB:xSm3+) were prepared by a solid-state route. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), diffuse reflection spectroscopy (DRS), and as well as photoluminescence (PL) spectra are used to exemplify the resulting samples. The structure and the Sm3+ dopants in the cation-borate phosphors were quantified, signifying the importance at Ca and Y sites. Under ultraviolet radiation-induced bright deep-red emissions with high color-purity up to 97.5%. The energy-migration (EM) between the Sm3+ ion was investigated both empirically and theoretically in the region of Sm3+ contents. Several theoretical-models were employed to simulate the lifetime of Sm3+ at various-concentrations, and the processes were investigated as a forced-electric dipole. The chemical-stability of CY0.95GB:0.05Sm3+ has also been investigated in this work. Interestingly, the CY0.95GB:0.05Sm3+ showed exceptional thermal-quenching resistance of>91.2% intensity at 400 K. The WLED containing CY0.95GB:0.05Sm3+ blended with the BAM:Eu2+ and CYAB:Tb3+ phosphor demonstrated low CCT ≈ 3843 K and high CRI ≈ 91.9. These findings were healthier than the industrial WLED having Y3Al5O12:Ce3+ and blue-LED.