Details of major studies demonstrating green synthesis of silicon nanoparticles (SiNPs)^a.

S. no.	Substrate	Nanoparticles' shape/arrangement	Size	Characterization	Reference
1	Coal fly ash	Amorphous mesoporous SiNPs	190–250 nm and pore size 3.5 to 4.5 nm	XRF, XRD, FESEM, TEM, porosity analyzer, FT-IR, TGA	116
2	Fly ash	Amorphous, aggregated spherical SiNPs	20–70 nm	FT-IR, Raman spectroscopy, XRD, FESEM-EDS, TEM, AFM	47
3	Sugarcane bagasse	Amorphous, spherical SiNPs	Around 30 nm	FT-IR, XRD, SEM and Micromeritics analyzer	23
4	Cynodon dactylon	Amorphous, spherical SiNPs	7 to 80 nm	UV-vis spectroscopy, FT-IR, DLS, XRD, SEM, TEM, EDAX	35
5	Bamboo	Crystalline, porous SiNPs	Around 200 nm	SEM, TEM, XRD	22
6	Rice husk	Biogenic porous SiNPs	25 to 30 nm	XRD, SEM, TEM, SAXS	48
7	Sugarbeet bagasse	Spheroid shaped SiNPs	38 to 190 nm	SEM-EDS, TEM, DLS, FT-IR, XPS, Raman spectroscopy	117
8	Sugarcane waste ash	Amorphous, mesoporous SiNPs	<1 to 100 μm	XRD, XRF, SEM, TGA, FT-IR, particle size analyzer	118
9	Maize stalk	Amorphous	30 nm	XRD, SEM, EDS, TEM, TGA, FTIR, Raman spectroscopy	49
10	Corn cob husk	Spherical shape	40 to 70 nm	SEM, STEM, EDX, FT-IR	119

^aX-ray fluorescence (XRF); X-ray diffraction (XRD); field emission scanning electron microscopy (FESEM); transmission electron microscopy (TEM); Fourier-transform infrared spectroscopy (FTIR); thermogravimetric analysis (TGA); atomic force microscopy (AFM); Dynamic Light Scattering (DLS); energy dispersive X-ray spectroscopy (EDAX); small-angle X-ray scattering (SAXS).