Electronic interaction between Mg porphyrin and TiO2 within a conducting brain like polypyrrole nanomatrix

摘要

Polypyrrole/Chlorophyll-a/TiO2 nanohybrid has been synthesized using FeCl3 as the oxidant where the morphology of the polymeric nanohybrid resembles the cerebral cortex of brain with large surface area leading to higher visible light absorption. The radical decrease in Chlorophyll-a emission intensity with the addition of TiO2 in steady state fluorescence and the shorter fluorescence lifetime of Chlorophyll-a which decreases with TiO2 addition substantiates the efficient electron transfer from Chlorophyll-a to TiO2 nanoparticle in brain like conducting polypyrrole matrix. The absence of any overlap between the emission spectrum of CHL-a (674 nm) and the absorption spectrum of TiO2 (365 nm) proves that Resonance Energy Transfer has not occurred and hence confirms the well-established electron accepting nature of TiO2(in presence of excited electron donors). The calculated free energy (ΔG_(ET)) value of-3.17 eV reveals that the quenching mechanism in this work involves electron transfer (with 44.67% efficiency) and focuses its probable application in DSSC.