Star-type melamine based conjugated carboxy functionalized porphyrin trimer for DSSCs: An efficient approach to clean, aggregation free and true energy generation

A novel, pi-conjugated melamine-based trimeric porphyrin dye with serving nine carboxylate linker groups has been prepared to use as a panchromatic dye for application in dye-sensitized solar cells (DSSCs). The star-shaped trimer was characterized by using Proton Nuclear Magnetic Resonance (NMR) Spectroscopy, Carbon Nuclear Magnetic Resonance Spectroscopy (CMR), Fourier Transformed Infrared Spectroscopy (FT-IR), UV-VIS Absorption Spectroscopy, Thermo-gravimetric analysis (TGA), Cyclic Voltammetry (CV) and Electrochemical Impedance Studies (EIS). CV studies revealed frontiers energy levels at-5.654 (HOMO) and-3.879 eV (LUMO) versus vacuum. The optical band gap evolved via absorption spectra measurements was found to be 1.49 eV. A planar perfect conjugation among three porphyrins sets up multiple push-pull communication and lowers the bandgap, while nine carboxylate linkers cover-up TiO2 surface effectively leading to better electronic dynamics. The DSSC set up using iodide-based redox couples forms a simple, stable, additive-free, truly energy generating device with 7.1% conversion efficiency, the highest among trimeric porphyrin category.

Automated summary

A novel pi-conjugated trimeric porphyrin dye with nine carboxylate linker groups was prepared for use as a panchromatic dye in dye-sensitized solar cells. The dye was characterized and shown to have high energy conversion efficiency.