Growth and Characterization of Films Containing Fullerenes and Water Soluble Porphyrins for Solar Energy Conversion Applications

Abstract

Thin films consisting of two fulleropyrrolidine derivatives 1 or 2 and a water-soluble porphyrin, TPPS4, were prepared by the Langmuir-Schäfer (LS, horizontal lifting) method. In particular, a solution of the fulleropyrrolidine in chloroform and dimethyl sulfoxide was spread on the water surface, while the porphyrin (bearing peripheral anionic sulfonic groups) was dissolved into the aqueous subphase. To the best of our knowledge, such a versatile method for film fabrication of fullerene/porphyrin mixed composite films has never been used by other researchers. Evidence of the effective interactions between the two components at the air-water interface was obtained from the analysis of the floating layers by means of surface pressure vs area per molecule Langmuir curves, Brewster angle microscopy, and UV-visible reflection spectroscopy. The characterization of the LS films by UV-visible spectroscopy reveals that in each case the two constituents behave as strongly interacting pi systems. The use of polarized light suggests the existence of a preferential direction of the TPPS4 macrocyclic rings with an edge-on arrangement with respect to the substrate surface, regardless which fulleropyrrolidine derivative is in the composite film. Atomic force microscopy investigations give evidence of morphologically flat layers even for LS transfer at low surface pressures. Photoaction spectra were recorded from films deposited by only one horizontal lifting onto indium-tin-oxide (ITO) electrodes, and the observed photocurrent increased notably with increasing transfer surface pressure for both 1/TPPS4 and 2/TPPS4 composite films. IPCE values are larger for 2/TPPS4 systems in comparison with 1/TPPS4 composite layers. Finally, a nonconventional approach to photoinduced phenomena is proposed by differential spectroscopy in the FT-IR attenuated total reflectance (ATR) mode.

Porphyrin Antennas on Carbon Nanodots: Excited State Energy and Electron Transduction

“…Until now, a large variety of non‐covalent and covalent systems based on porphyrins and carbon nanomaterials, such as fullerenes, carbon nanotubes, or graphene, have been described . Pioneering photophysical properties, both in solution and in the solid state, have laid the foundations for their use as active components in photovoltaic devices . A substantial impact on the ground and excited state interactions between porphyrins and fullerenes, carbon nanotubes, or graphene have been documented in covalently linked systems .…”

Effect of Fullerene on Photocurrent Performance of 6‐O‐Porphyrin‐2,3‐di‐O‐stearoylcellulose Langmuir‐Blodgett Films

“…This H 2 PCS-C 60 systems realized greater IPCE values for the anodic photocurrent generation than ferrocene-porphyrin-C 60 triads systems (0.70%), [15] special-pair mimic porphyrin assemblies systems (0.55%), [36] and water soluble porphyrin-functionalized C 60 systems (0.29%). [21] On the other hand, Marczak et al have achieved an IPCE value of 2.5% from the LB twenty-layer films of zinc porphyrinimidazole-functionalized C 60 dyad based on metal-ligand axial coordination interactions; The strong interaction between porphyrin and C 60 may enhance photocurrent performance. [22] Overall, cellulose-based photocurrent generation systems were greatly improved by mixing C 60 molecules.…”

“…[16] There have been several efforts to fabricate porphyrinfullerene systems by the LB technique, in an effort to prepare highly ordered multilayer films and therefore achieve efficient photo-to-current conversion properties. Recent examples of double linked porphyrin-fullerene dyads [17,18] and porphyrin-fullerene self-assemblies [19][20][21][22] are based on covalent bonds and electrostatic/metal-ligand axial coordination interactions of the functionalized fullerene to porphyrins, respectively. Formation of stable, uniform, and highly ordered LB films can result from the prevention of aggregation, which is the sever tendency of fullerenes, [23] by attaching a hydrophilic group and/or regulating filmforming conditions.…”

Nanocellulose/Fullerene Hybrid Films Assembled at the Air/Water Interface as Promising Functional Materials for Photo-electrocatalysis

“…Specifically, the electrostatic interaction between nanocellulose and FP Langmuir layers was probed by introducing in the subphase a CNCs competitor: the meso-tetraphenylporphyrine-4,4 ,4 ,4 -tetrasulfonate (TPPS4). This anionic porphyrin was chosen due to its well-established ability to bind to amphiphilic cationic FPs that were layered at the air-water interface, enabling the deposition of porphyrin-FP dyads by an analogous LS approach [5,58,59]. Moreover, the sulfonate moieties that are present in TPPS4 structure are chemically similar to the sulfate groups of the proposed anionic CNCs.…”