Synthesis, Characterization, and Fluorescence Properties of Mixed Molecular Multilayer Films of BODIPY and Zn(II) Tetraphenylporphyrins

Abstract

A new azido functionalized 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) has been synthesized to achieve spectral complementarity to a Zn(II) tetraphenylethynyl porphyrin (ZnTPEP). Mixed multilayer films were assembled on glass and quartz up to 10 bilayers thick in a layer-by-layer (LbL) fabrication process using copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) to couple these two dyes together with a tris-azido linker. By varying the amount of BODIPY in the CuAAC reaction solutions for the azido linker layers, we achieve tunable doping of BODIPY within the porphyrin films. We are able to demonstrate linear film growth and determine thickness by X-ray reflectivity (XRR). XRR data indicated that lower BODIPY loading leads to higher porphyrin content and slightly thicker films. Fluorescence emission and excitation spectra of the mixed multilayer films show efficient quenching of the BODIPY singlet and enhanced ZnTPEP emission, suggesting efficient energy transfer (EnT). The ease of fabrication and tunability of these films may serve as potential light harvesting arrays for molecular-based solar cells.

Click Chemistry on NiO Photocathode to Postfunctionalize a Diketopyrrolopyrrole Sensitizer by Naphthalene Diimide Electron Acceptor

“…10,11 Notable examples of this approach are the modification of flat surfaces of gold 12 and silica, 13 of spherical nanoparticles, 14 and even mesoporous metal oxide layers. 15,16,17,18 Except for the recent elegant works of Dinolfo and coworkers on flat ITO substrates, 19,20 surface post-functionalization is, however, often limited to the immobilization of a single molecular component via a simple alkyl chain terminated by azido or alkyne group and grafted on the surface via a carboxylic or alkoxysilane anchoring group. On the other hand, it is well accepted that molecular complexity is a prerequisite to achieve elaborated functions.…”

Supramolecular BODIPY Dye Architectures for Advanced Light Harvesting and Energy Transfer Applications

“…[120][121][122][123][124] The efficiency of the intramolecular energy transfer in antennae assemblies depends on the extent of electronic coupling between the chromophores which could be modulated either by the bridge or the special orientation of the units. 125,126 Triazole bridged BODIPY-Zn or BODIPY-Ni porphyrin conjugates containing one BODIPY and one porphyrin (dyad, 1.20 127 and 1.21 128 ), three BODIPYs and one porphyrin (tetrad, 1.22 128 ) and four BODIPYs and one porphyrin (pentad, 1.23 128 ) were studied. The absorption spectra shows increase of roughly three and four times in the BODIPY (donor) π−π* transition.…”

Azides and Porphyrinoids: Synthetic Approaches and Applications. Part 1—Azides, Porphyrins and Corroles

“…For instance, in 2015 Topka and Dinolfo explored the CuAAC approach in combination with the layer-by-layer (LbL) process to assemble over an azide-rich functionalized glass or quartz the alkynyl porphyrin P1-Zn, the azide-BODIPY 17 and the tris-azido linker 18 to obtain the multilayer film GQ-MP1-Zn (Scheme 20) [49]. The LbL process started with the conjugation of the ethynyl P1-Zn with the azide functionalized glass or quartz surface (prepared by anchoring 11-azidoundecyltrimethoxysilane to glass/quartz slides surface exposed to a piranha solution) followed by reaction of the remaining ethynyl moieties with a mixture of azide-BODIPY 17 and the tris-azido linker 18 in order to allow the formation of another porphyrinic layer.…”

“…In this way, it was possible to add multiple layers and consequently to modulate the optical density through their thickness. In fact, this strategy is very convenient to generate multichromogenic (donor-acceptor) energy transfer assemblies to develop full spectral light harvesting materials for DSSC devices [49]. The same research group, by following the LbL process and through a click approach, prepared other porphyrin-based molecular multilayer films (ITO-MP1-Zn) on indium tin oxide (ITO) electrodes for photovoltaic and photogalvanic devices [50].…”