A Photoelectrochemical Study of Bioinspired 2-Styryl-1-Benzopyrylium Cations on TiO2 Nanoparticle Layer for Application in Dye-Sensitized Solar Cells

Abstract

In the present work, five 2-styryl-1-benzopyrylium salts and their relative self-assembly processes towards TiO2 nanocrystalline layers were evaluated as photosensitizers in dye-sensitized solar cells (DSSCs). Integration of these 2-styryl-1-benzopyrylium salts with the semiconductor allow for the performance of highly specific functions suitable for smart applications in material science. Spectroscopic and photoelectrochemical measurements conducted on these five bio-inspired dyes, in solution and upon adsorption onto titanium dioxide films, allowed detailed discussion of the anchoring ability of the different donor groups decorating the 2-styryl-1-benzopyrylium core and have demonstrated their ability as photosensitizers. Our results suggest that the introduction of a dimethylamino group in position 4′ of the 2-styryl-1-benzopyrylium skeleton can alter the conjugation of the molecule leading to larger absorption in the visible region and a stronger electron injection of the dye into the conduction band of TiO2. Moreover, our experimental data have been supported by theoretical calculations with the aim to study the energy of the excited states of the five compounds. In this specific case, the simulations reported contributed to better describe the properties of the compounds used and to help create the necessary basis for the design of new and targeted bio-inspired molecules.

Self-Assembly of Organic Nanomaterials and Biomaterials: The Bottom-Up Approach for Functional Nanostructures Formation and Advanced Applications

“…DSSCs represent a new class of solar cells, which are developed by the imitation of the photosynthesis process, by using low-price abundant materials, such as TiO 2 , sensitizers and simple manufacturing technology [234,235]. Since Gratzel and co-workers [234], many researchers have used the self-assembly approach for the design of many new nanostructured dyes and new sensitization methods for the development of DSSCs [236][237][238][239][240]. These approaches employ a series of new self-assembly strategies that eliminate expensive synthesis steps and realize a high yield [241][242][243][244][245].…”

Editorial-Special Issue “Macromolecular Self-Assembly Materials: From Modeling to Advanced Applications”

“…The Special Issue "macromolecular self-assembly materials: from modeling to advanced application" comprises one review article concerning the self-assembly processes involving organic materials [1], and three original research papers that provide important insights into the self-assembly process of inorganic [2] and hybrid materials [3,4]. Finally, the Special Issue included a theoretical study concerning the complex self-assembly process involved in a model system composed of functionalized hard-soft dimers [5].…”

“…The Special Issue also includes two interesting studies concerning the self-assembly of hybrid nanomaterials [3,4]. Yu et al [3] proposed a new facile microfluidic route (based on a three step assembly process) for the synthesis of novel core-shell composite/hybrid polymeric microparticles doped with organic and inorganic nanoparticles.…”

“…In the article of Calogero at al. [4], five 2-styryl-1-benzopyrylium salts and their relative self-assembly processes toward TiO 2 nanocrystalline layers (semiconductor substrate) were evaluated in their efficiency as photosensitizers in dye-sensitized solar cells (DSSCs). The spectroscopic and photoelectrochemical investigation conducted on these five bio-inspired dyes, in solution and upon adsorption onto titanium dioxide films, allowed for a detailed description of the anchoring ability as well as the ability as photosensitizers of the different donor groups decorating the 2-styryl-1-benzopyrylium core.…”