Indole-7-carboxaldehyde functionalized silver and gold nanoparticles as novel metal-organic laser power limiting composites

Efforts were done to enhance the nonlinear optical and optical power limiting responses of Indole-7-carboxaldehyde (I7C) after the addition of silver and gold nanoparticles. The investigations were done theoretically as well as experimentally. The reactivity parameters and potential surfaces established strong intermolecular charge interactions between metal trimer and I7C. The diffraction pattern for both I7C+AgNPs and I7C+AuNPs indicated the perfect crystallinity of the samples. The band gap of I7C+AgNPs (2.08 eV) was less than that of I7C+AuNPs (2.34 eV). The polarizability of I7C was enhanced after the addition of gold and silver nanoparticles. The value of first-order hyperpolarizability of probe I7C was observed as 4.24 × 10 −30 esu which was increased to ten times for I7C+AgNPs and eighteen times for I7C+AuNPs. The increased value of first-order hyperpolarizability supported enhanced nonlinear optical characteristics of I7C+AgNPs and I7C+AuNPs. Further, the reduction in experimentally obtained optical limiting threshold and increment in the nonlinear absorption coefficient reflects early attenuation of the nonlinear optical and enhanced optical limiting activity of I7C+AgNPs and I7C+AuNPs. • NLO activity of Indole-7-carboxaldehyde combined with AgNPs and AuNPs were studied. • High value of first-order hyperpolarizability indicated the higher NLO activity of composites. • Valley-like pattern in Z-Scan spectra indicated its Nonlinear optical activity. • The decrement in transmittance with Z indicates reverse saturable absorption. • Strong optical limiting was observed after the addition of AuNPs.