Molecular Engineering of Potent Sensitizers for Very Efficient Light Harvesting in Thin-Film Solid-State Dye-Sensitized Solar Cells

Abstract

Dye-sensitized solar cells (DSSCs) have shown significant potential for indoor and building-integrated photovoltaic applications. Herein we present three new D-A-π-A organic sensitizers, XY1, XY2, and XY3, that exhibit high molar extinction coefficients and a broad absorption range. Molecular modifications of these dyes, featuring a benzothiadiazole (BTZ) auxiliary acceptor, were achieved by introducing a thiophene heterocycle as well as by shifting the position of BTZ on the conjugated bridge. The ensuing high molar absorption coefficients enabled the fabrication of highly efficient thin-film solid-state DSSCs with only 1.3 μm mesoporous TiO2 layer. XY2 with a molar extinction coefficient of 6.66 × 10(4) M(-1) cm(-1) at 578 nm led to the best photovoltaic performance of 7.51%.

Dye-sensitized solar cells for efficient power generation under ambient lighting

“…1a) brings out the outstanding attributes of both dyes. The recently introduced XY1 sensitizer, a D-A-π-A dye, has a very high molar extinction coefficient and spectral response that extends beyond 700 nm, whereas D35 is an organic D-π-A dye endowed with a judiciously designed arylamine donor structure, which suppresses electron recapture by the Cu(II) complex from the TiO 2 conduction band and generates a high open-circuit potential 30,32 . Even during the early stage of this study we found that the XY1 dye in combination with D35 showed impressive photovoltaic metrics, specifically under indoor and ambient light illumination.…”

First Report of Chenodeoxycholic Acid–Substituted Dyes Improving the Dye Monolayer Quality in Dye‐Sensitized Solar Cells

“…A common strategy for reducing aggregation for both metal‐complex dyes and organic sensitizers is the use of alkyl or alkoxy chains, present in just about all of the highest‐performing sensitizers . One of the more exciting examples of a novel antiaggregation unit was the use of a glucose derivative attached by click chemistry to a dianchoring phenothiazine sensitizer, reported by Manfredi et al.…”

Dissymmetrization of Benzothiadiazole by Direct C–H Arylation: A Way to Symmetrical and Unsymmetrical Elongated π‐Conjugated Molecules

“…[35][36][37][38][39] In a general manner, this last strategy offers great advantages: owing to the reduced number of reactants, the workup is simplified and the production cost is even reduced. As molecule 1 is not yet commercially available but is a unique building block for creating symmetrical or unsymmetrical π-conjugated D-A molecules, [42][43][44][45][46][47][48] the suggestion of an effective and simple synthetic protocol should be of interest to many chemists. In this spirit, we recently synthesized benzothiadiazole (Bz)-based symmetrical molecules by using dibromobenzothiadiazole (diBrBz) and 2thiophenecarbaldehyde (ThCHO) as starting materials (Scheme 1, top) through phosphine-and additive-free direct C-H arylation.…”

“…Thus, it may be considered environmentally and economically attractive as well as efficient. So far, there have been only a few reports on the synthesis of 1 in good yields (i.e., more than 40 %), and the related synthetic protocols were based on Suzuki [43][44][45][46][47] or Stille [48] coupling reactions (see (thiophen-2-yl)benzo [1,2,5]thiadiazole (54 % intermediate yield), which was then formylated through a classical route to afford 1. [40] In the present study, we investigated the disymmetrization of the Bz unit through the synthesis of the mono-adduct 5-(7bromo-2,1,3-benzothiadiazol-4-yl)-2-thiophenecarbaldehyde (1, Scheme 1).…”