“…Admitting the fact that gold and silver are the most explored among the family of noble metals, platinum (Pt) has recently attracted attraction due to its high fluorescence, − lesser cytotoxicity, and excellent catalytic activity. − Pt metal is used as a catalyst in many reactions and is a familiar candidate in hydrogen evolution reactions. Larger Pt nanoparticles, under 532 nm excitation, reveal a switching behavior from saturable absorption (SA) to reverse saturable absorption (RSA) as the input intensity is increased. , At high intensities, the transient absorption by free carriers caused by the interband (d-sp) transition becomes more prominent, resulting in RSA.…”