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

• Published in: Materials chemistry and physics Vol. 287; p. 126312
• Main Authors: Bhuse, Darpan V., Bhuse, Vijaykumar M., Bhagat, Pundlik R.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2022
• Subjects: Cyclic voltammetry; Dye-sensitized solar cells; Melamine; Photosensitizers; Porphyrins; Cyclic voltammetry; Dye-sensitized solar cells; Melamine; Porphyrins; Photosensitizers
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2022.126312

A novel, π-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. •Design and synthesis of star-shaped, metal-free, multiple D-π-A type porphyrin small molecule sensitizer for DSSC.•The highest nine carboxymethyl groups give excellent anti-aggregation stability and electronic coupling.•An electron-deficient planar triazine core sets in-plane- π stacking over TiO2 surface.•A perfect energy alignment of dye frontiers with TiO2 and redox couple and the shortest charge injection time (0.2 ms).•A DSSC evolved as additive-free, stable, true energy-generating with a record 7.1% PCE and 0.451 eV Eloss.