Tuneable fluorescent, recombination pathways of biogenic Au-SiO2 nanospheres from rice husk: An optical study

This work explores the optical properties of amorphous silica (ASO) and gold incorporated silica (Au-SiO2) prepared from Rice husk (RH) which is a biomass and also an environment waste. X-ray diffraction study shows the amorphous nature of prepared SiO2 and diffraction peaks related to gold for Au:SiO2 samples. Optical absorption study reveals the surface plasmon resonance (SPR) band centred at 525 nm. Photoluminescence (PL) study expose the light emitting nature of prepared SiO2 and Au:SiO2 at different excitation wavelengths. Variations in PL of SiO2 while incorporating Au is attributed to the structural modifications and metal enhanced fluorescence. Time resolved photoluminescence (TRPL) conducted at different excitation and emission wavelengths show the three exponential emission decay of SiO2 and Au:SiO2 samples.