Third order NLO and second hyperpolarizability of functional porphyrin based polyimides

Porphyrin-POM hybrid materials with excellent NLO properties are supposed to be a worthy entrant for forthcoming telecommunication, optical fibers, optical data storage and optical limiting devices, but due to adverse solubility problems, they are replaced by polymeric materials. Herein, we assessed third order NLO and second hyperpolarizability of porphyrin-polyimide compounds (NH-PI and Zn-PI) synthesized from the reaction of 4,4ʹ-hexafluoroisopropylidene-diphthalic anhydride (6FDA) with C 44 H 32 N 6 (NH-DATPP) and C 44 H 30 N 4 Zn (Zn-DATPP) porphyrins under ambient conditions. The Z-scan measurement of these compounds revealed reverse saturation absorption as well as self-defocusing performance. Zn-PI showed an enhancement in γ value (2.214 × 10 −29 esu) as compared to the NH-PI (1.879 × 10 −29 esu) revealing significant role of Zn ion in charge transfer process. On the other hand, Zn-DATPP exhibited χ (3) value of 7.829 × 10 −11 esu which is significantly lower than the value seen for the compound NH-DATPP (15.649 × 10 −11 esu) showing inverse effect due to ruffled deformation in normal coordination structure of metalloporphyrin. Furthermore, this work provides a pave to modulate the NLO response by fine structural modification in porphyrin-polyimides. • The decrease in χ (3) value in Zn-DATPP is due to the loss of planarity and conjugation. • Both the delocalization of electronic cloud and co-planarity of polyimide structure favored the charge transfer. • The 3rd order NLO can be improved by the introduction of Zn ion in polyimide framework. • The strong fluorescence quenching showed that the electron transfer and/or energy transfer process has occurred.