Organic dyes containing nonsubstituted aryl amino moieties and azobenzene units for dye‐sensitized solar cells

Abstract

A series of novel sensitizers were successfully synthesized utilizing azobenzene as a π‐linkage unit for the D–π–A structure. A slight red shift on the absorption spectra and λonset of the sensitizers could be observed when the thienyl group was introduced to the acceptor moiety (A). In addition, replacing the donor moiety (D) from carbazole to diarylamino could lead to a negative shift (approximately 0.3 V) in the first oxidation potential. DFT calculation was also carried out and the trend of calculated HOMO–LUMO gaps was consistent to the experimental data obtained from the CV results (DT1 < DT2 < DT3 < DT4). These sensitizers were then employed in dye‐sensitized solar cells to investigate their photovoltaic performances. Highest power conversion efficiency (PCE) of 0.84% was achieved for DT1‐based DSSC according to its most bathochromic absorption spectrum.

Metal‐free Organic Dyes Featuring an Azobenzene Bridge for Photochromic Dye‐Sensitized Solar Cells

“…In addition, the electrical and optical properties of the dyes adsorbed on the TiO 2 surface (referred to dye/TiO 2 complex) were calculated to provide more reliable information. In the dye/TiO 2 complex, sufficiently large (TiO 2 ) 9 anatase cluster was applied in accordance with our previous studies, [28] and carboxylate group of each dye was anchored to the surface of TiO 2 via bidentate chelating mode, which is generally accepted to mimic the realistic environment of DSSCs. [31,32] Figure S1 shows the optimized structures of the trans (E) and cis (Z) geometries of the isolated dyes and the dye/TiO 2 complexes.…”

“…[20][21][22][23] Furthermore, a few groups have explored asymmetric azobenzene derivatives for photoresponsive DSSCs, both theoretically and experimentally. [24][25][26][27][28] However, the photoswitching properties of these systems, which are related to trans-cis isomerization, are yet to be characterized in detail.…”

An organic dye containing electron‐rich cyclopentadithiophene for dye‐sensitized solar cells with an efficiency over 28% at 6,000 lux

“…Since the seminal report of DSSCs in 1991, [ 10 ] the light absorbing sensitizers of the DSSCs have been widely investigated. In the push‐pull designs of DSSC‐sensitizers, the D ‐π‐A [ 11–14 ] or D ‐A‐π‐A [ 15–17 ] frameworks with various modifications by introducing double donors, [ 18–21 ] di‐anchoring groups, [ 22–25 ] or extended π‐conjugated spacers [ 26,27 ] are well‐known strategies that have been applied for tuning the photophysical and electrochemical properties of sensitizers. However, most of the recent reports are predominantly followed a D‐A‐π‐A strategy, which the additional electron‐deficient auxiliary acceptor prevails potential improvements in photophysical and electrochemical properties as well as the performance and stability of the DSSCs compared to the traditional D‐π‐A design.…”

Dye-sensitized solar cells based on dimethylamino-π-bridge-pyranoanthocyanin dyes

“…Appropriate π-conjugation between D and A can broaden the absorption wavelength range and increase the molar extinction coefficient of the molecules. (Mahmood, 2016;Toan et al, 2019;Zhang et al, 2019) The insertion of C=C bonds is one way to extend the π-conjugation and has been reported to improve the overall efficiency of devices by extending the conjugation in the dye chromophore. (Teng et al, 2010) Nevertheless, the nature of the π-segment can also affect the energetics and the kinetic characteristics of the TiO2/dye/electrolyte interface and hence influence the electron injection and regeneration processes.…”