Oligocarbazole‐Based Chromophores for Efficient Thin‐Film Dye‐Sensitized Solar Cells

Abstract

Carb your enthusiasm: Carbazole-based sensitizers with high extinction coefficients are synthesized for application in dye-sensitized solar cells (DSCs). The dyes perform efficiently with both iodine and cobalt electrolytes, showing power conversion efficiencies of up to 5.8% on TiO₂ films of 15 μm thickness, and retaining 90% of their efficiency in devices with thinner films.

Functionalization of a Ruthenium–Diacetylide Organometallic Complex as a Next‐Generation Push–Pull Chromophore

“…These values clearly demonstrate the ability of the ruthenium–diacetylide complex 6 to work efficiently as a photosensitizer in DSCs. Moreover, in standard devices with an iodine‐based electrolyte, compound 6 outperforms fully organic carbazole‐based dyes of similar structure, reported by us and others 18b. 24…”

Molecular engineering of carbazole-fluorene sensitizers for high open-circuit voltage DSSCs: Synthesis and performance comparison with iodine and cobalt electrolytes

“…cm -1 ) observed, as expected, for the three dyes confirm the beneficial effect of the fluorene core inserted into the π-conjugated bridge since the ε of JM1-JM3 is much higher than those of other carbazole-based dyes reported by us and others [6][7][8][9][10][20][21]. Due to the presence of the fluorene motif in the molecular backbone, JM1-JM3 are also strongly fluorescent dyes with an emission maximum at around 600 nm in dichloromethane (Fig.…”

“…5, the dyes JM1-JM3 exhibit a broad IPCE profile in standard DSSC devices (TiO2 film thickness = 7.5 µm + 5.5 µm ; electrolyte Z960) with a large plateau in the visible range and a maximum exceeding 80 % around 450 nm. It is worth to note that these performances are much better than those reported for other carbazole-based dyes employed with a similar electrolyte[6][7][8]10]. However, as reported before with this kind of organic dyes under the same conditions,[15,28] the open-circuit photovoltage values remained relatively low (Voc ~ 630 mV) due the mismatch between the redox potential of I -/I3 -and the dye oxidation potential.…”

“…Additionally, the photosensitizer can influence key electron transfer processes occurring at the semiconductor/dye/electrolyte interface which also determine overall efficiency of the device. Bearing in mind that carbazole-based dyes are good candidates to reach high open-circuit photovoltage values [6][7][8][9][10], and therefore good power conversion efficiencies (PCE) in DSSCs, we intended to synthesize a new family of push-pull photosensitizers bearing carbazole as the electron donating unit. Accordingly, we herein describe a new design strategy to prepare novel organic D-π-A sensitizers with high light-harvesting capacity.…”

Intramolecular Path Determination of Active Electrons on Push‐Pull Oligocarbazole Dyes‐Sensitized Solar Cells

“…The electron donating part of the studied chromophores is thus based on the carbazole motif, which ensures good light absorption properties, but also guarantees an energy level of the ground state of the molecules suitable for the use of electrolytes with high oxidation potential at the other end of the dyes. The cyanoacrilic acid group acts as both an electron acceptor and an attachment group …”