Dual-Function Al3+/B3+ Introducing Strategy for Silica Phase Control and Enhanced Interstitial Deep-Red Emission of Samarium (II)

The exploration of highly efficient deep-red luminescent materials is crucial for advancing white light-emitting diodes (LEDs), indoor plant growth, and polycrystalline silicon solar cells. Here, we realize sharp deep-red emission from interstitial Sm 2+ in silica through a dual-function Al 3+ /B 3+ codoping strategy. The interstitial Sm 2+ exhibits a dominant emission centered at 683 nm with a broad excitation band ranging from 250 to 550 nm. The co-introduction of Al 3+ and B 3+ facilitates the phase transition from α -quartz to α -cristobalite, which is more favorable for samarium accommodation, as revealed by density functional theory (DFT) calculations. Meanwhile, the co-introducing of Al 3+ and B 3+ increases the amount of Sm 2+ as proved by the UV-Vis-NIR diffuse reflectance and X-ray absorption near-edge structure (XANES) spectra. These two factors synergistically enhance the emission intensity of Sm 2+ compared with that in the Al 3+ and B 3+ singly doped samples. Specifically, Al 3+ , B 3+ and Sm 2+ doped α -cristobalite (SiO 2 :Al 3+ ,B 3+ ,Sm 2+ ) presents heat resistance up to 600°C and great water resistance abilities as proved thermally treated in air and hot-water immersion assessments. This work demonstrates a strategy to realize and enhance the Sm 2+ emission by interstitial occupation and microenvironment adjustment.