Syntheses and optoelectronic properties of amino/carboxyphenylporphyrins for potential use in dye-sensitizedTiO₂solar cells

Abstract

New mixed-substituent amino/carboxyphenylporphyrins for a dye-sensitized TiO 2 solar cell were prepared using several synthetic routes. The reaction of 4-carbomethoxy-and 4-acetamidobenzaldehydes with pyrrole in propionic acid under aerobic conditions afforded mixtures of mixed amide/ester substituted tetraphenylporphyrins which were separated using centrifugal chromatography then deprotected to give the target compounds. Condensation of p-nitrophenyldipyrromethane with 4-carbomethoxybenzaldehyde in CH 2 Cl 2 catalyzed by trifluoroacetic acid, followed by oxidation with dichlorodicyanoquinone gives trans-dicarbomethoxy/ dinitrophenylporphyrin, which when treated with SnCl 2 and HCl affords the trans-diamino/dicarboxy derivative, trans-TA 2 C 2 PP. Commercially available tetrakis-5,10,15,20-(4-carboxyphenyl)porphyrin (TCPP) was converted to mixtures of mixed amino/carbomethoxyphenylporphyrins using hydroxylamine hydrochloride in polyphosphoric acid with methanol workup. Relative yields and product distributions from each route are discussed and the optoelectronic characteristics of the synthesized porphyrins were studied using UV-visible spectroscopy and cyclic voltammetry. Copyright

Porphyrins and phthalocyanines in solar photovoltaic cells

“…More recent work has studied mixed amino/carboxyphenylporphyrins, using the amino groups as possible nucleation points for polymerization of aniline to create solid-state solar cells [118]. Using 5-(4-aminophenyl)-10,15,20-tris(4-carboxyphenyl)porphyrin in a liquid electrolyte solar cell with a polyaniline counter electrode gave an overall efficiency of 1.1% [119].…”

The effects of heavy atoms on the exciton diffusion properties in photoactive thin films of tetrakis(4-carbomethoxyphenyl)porphyrins

“…Solution UV-Vis spectra of the three derivatives have identical molar absorptivities and absorption peaks in the Soret band at 418 nm (ε = 450 x 10 3 M -1 cm -1 ) along with four Q bands spanning the visible region (514, 548, 591, and 646 nm), Q 4 , Q 3 , Q 2 , and Q 1 respectively. 38,40 This red-shift is indicative of energy level shifts caused by porphyrin stacking, while the broadening of the Soret band is attributed to the increase of the π-π interactions as a result of porphyrin stacking in thin films.…”

“…Porphyrins are well known for their efficiency in generating long-lived triplet excited states through intersystem crossing (ISC), and are widely used to generate singlet oxygen for photodynamic therapy applications. 38 These were separated using centrifugal chromatographic techniques to obtain high purity TBCM 3 PP and TCM 3 IPP. 32,[34][35][36][37] Using TCM 4 PP and mixed-substituent bromophenyl or iodophenyl TXCM 3 PP derivatives, we have investigated how increasing the generation of triplet states in porphyrin thin films affects singlet exciton diffusion lengths and photocurrent efficiency.…”

“…Preparation of Porphyrin Derivatives 5,10,15,20-Tetrakis(4-carbomethoxyphenyl)porphyrin (TCM 4 PP): TCM 4 PP was obtained using previously reported methods 38. The XRD θ/2θ patterns were obtained using a Panalytical X'Pert Pro MPD with Ni filtered Cu Kα radiation from a fixed anode at 45 kV, 40 mA.…”

Fluorescent Paper Strips for Highly Sensitive and Selective Detection of Nitroaromatic Analytes in Water Samples

“…CV measurement is one of the widely used experimental approaches . Onset oxidation and reduction potentials are used to estimate the HOMO and LUMO levels using an empirical formulation.…”