Molecular engineering of starburst triarylamine donor with selenophene containing π-linker for dye-sensitized solar cells

Abstract

New starburst triarylamine donor with selenophene containing π-linker were synthesized. Such donor can minimize dye aggregation on TiO2 and slow down charge recombination kinetics in dye-sensitized solar cells.

Starburst Triarylamine Donor-Based Metal-Free Photosensitizers for Photocatalytic Hydrogen Production from Water

“…The synthetic routes for S1 – S3 are shown in Schemes and S1 (in the Supporting Information, SI). The precursors 7a – 7c were prepared by Suzuki coupling reaction of the corresponding intermediates with the arylboronic ester, in which the aryl group is the starburst triarylamine unit . Eventually, two different Knoevenagel condensation approaches were launched to prepare S1 and S3 by using cyanoacetic acid, while S2 was obtained through the deprotection of the ethyl group in 7b under basic conditions.…”

“…Herein, three metal-free PSs ( S1 – S3 ) were synthesized with either a donor−π–acceptor (D−π–A) or donor–acceptor−π–acceptor’ (D–A−π–A′) framework, in particular with the same starburst triarylamine donor moiety (D) (Figure ). These molecules match well with the prerequisites of PSs in both photocatalytic H 2 generation and dye-sensitized solar cells (DSSCs), and the corresponding studies have been carried out.…”

“… It was found that these PSs exhibited very similar R rec values, and thus similar V oc values from their J – V curves were accounted. This circumstance is best explained by the dominant influences brought from the same starburst triarylamine donor moiety in S1 – S3 since this functional group was proven to be valid in inhibiting dye aggregation and charge recombination at the interfaces due to its bulky and hydrophobic nature …”

Molecular Engineering of Robust Starburst-Based Organic Photosensitizers for Highly Efficient Photocatalytic Hydrogen Generation from Water

“…An ideal PS should be able to resist water corrosion and have broad spectral absorption and high charge carrier mobility to achieve effective charge separation. ,, Metalated PSs anchoring on TiO 2 , especially ruthenium and iridium complexes, have been used in photocatalysis due to their attractive performance and effective metal-to-ligand charge transfer. ,− From the viewpoint of reducing the energy costs that are required to fabricate solar water-splitting devices, metal-free organic dyes have emerged as an attractive cost-effective alternative over metal complexes for photocatalysis. Organic dyes offer structural versatility to tune the absorption wavelengths with superior molar extinction coefficients (ε) and charge-transfer ability as compared with the conventional metalated dyes. ,− In particular, π-conjugated molecules with electron donor–acceptor moieties for effective intramolecular charge transfer (ICT) exhibit noticeable photovoltaic conversion efficiencies (PCEs) for dye-sensitized solar cell (DSSC) applications. Due to such convenient ICT modulation, large capacity and cross section for absorption, and efficient charge separation upon photoexcitation, organic PSs are also applicable to water splitting. ,− However, most of the reported rod-shaped organic PSs are prone to aggregate on the TiO 2 surface and induce intermolecular quenching .…”

The function of Chalcogenophene in the Cyclomatelated Ring of the Cycloruthenated Dyes applied in Dye-Sensitized Solar Cell

“…On the other hand, NCS-free cycloruthenated sensitizers have the unique advantage (compared to NCS-containing ruthenium dye) of being able to acutely control the HOMO energy through the modification of the substituents on the anionic cyclometalated ring and are more stable due to the lack of monodentate NCS ligands. − Recently, we have reported a good-efficiency NCS-free cycloruthenated dye (DUY24) with thiophene as a part of the cyclometalated ring in the ancillary ligand . It was also shown that an organic dye containing a selenophene π-bridge has higher absorption coefficient and longer λmax compared to that containing the thiophene ring. − NCS-containing ruthenium (not the NCS-free cyclometalated structure) dye with selenophene as the substitute in the bipyridine ancillary ligand also shows higher absorption coefficient and lower MLCT energy compared to its thiophene analogue . In this work, we replaced the thiophene ring in DUY24 with a softer selenophene (DUY24-Se) or a harder furan (DUY24-O) analogue to prepare the other two NCS-free cycloruthenated dyes with a molecular size similar to DUY24.…”