Fig. 1 (a) and (b) SEM images of the SiQD phosphors. (c) TEM image of the SiQD-phosphors. (d) Photographs of the SiQD-phosphor suspension in toluene under room light (left) and 365-nm near-UV excitation (right).

Fig. 2 (a) PL spectra of the SiQD-phosphor suspension in toluene, with 320-nm (orange curve), 365-nm (red curve), 400-nm (green curve) and 440-nm (blue curve) excitations, respectively. (b) PLQY versus excitation photon energy. (c) Excitation (red solid line) and absorbance (blue dotted line) spectra. (d) FTIR-ATR spectra of the dried SiQD-phosphor powders at different stages of the synthesis, as-harvested (blue dotted line), after HNO₃ etching (green dotted line) and after alkyl silane treatment (red solid line). ν and δ mean stretching mode and deformation mode, respectively. (e) Electronic band structure of the SiQD-phosphors. The green, red, blue rectangles represent the energy band gaps of the silicon core, SiQD and silicon oxide, respectively.

Fig. 3 (a) and (b) Electroluminescence spectra (area-normalized) and photographs of Sample 1 and Sample 2, respectively. The spectrum of an ideal incandescent source (gray dashed line) is superimposed for comparison. (c) Specifications of the lighting quality produced by Sample 1, Sample 2 and the ideal incandescent source. Duv specifies the deviation of a light from a blackbody radiator reference. R9 reports the rendering score of a light on a saturated red reference. LER (lm W_opt⁻¹) represents the spectral efficiency. CQS Qa is a metric introduced by researchers at the National Institute of Science and Technology (NIST) as an update from the CRI standard.