Influence of nitro group substitution at molecular ligand on optical, structural, charge-transport and photovoltaic properties of Sn (II) phthalocyanine

The effect of nitration on the optical, structural, charge-transport and photovoltaic properties of tin (II) phthalocyanine (SnPc) is investigated in the form of thin film sandwiched devices, by analyzing its electrical, optical and cyclic voltametric behavior. Further, the effect of nitration on SnPc is described in terms of decrease in HOMO–LUMO position, widening of CT band in absorption spectra and shifting in characteristics metal sensitive Raman peak contributed by C–N–C bridge bond resulting rearrangement in molecular stacking. Charge conduction mechanism has been discussed by evaluating charge carrier concentration, their mobility and the nature of the localized trapping states. The AFM image has been recorded to understand the morphological change in thin film material in terms of alteration in crystalline nature. The devices show p-type semi conducting behavior of SnPc as it forms a Schottky barrier with low work function Al electrode (4.28 eV) and Ohmic contact with high work function ITO electrodes (4.8 eV), respectively.