Enhanhanced third order optical nonlinearity in ultrathin amorphous film of tetraphenyl-porphyrin in picosecond regime

•Quality thin film of 5,10,15,20-Tetraphenyl-21H,23H-porphine (TPP) is fabricated.•The developed thin film exhibits excellent fluorescence emission.•TPP film depicts saturation absorption and self-defocusing optical nonlinearity.•The effective nonlinear absorption coefficient (βeff) is of the order of 10−6 m/W.•Thin film portrays enhanced NLR index (n2) of the order of 10−13 m2/W.