Organic Sensitizers Featuring a Planar Indeno[1,2‐b]‐thiophene for Efficient Dye‐Sensitized Solar Cells

Abstract

An efficient organic sensitizer (JK-306) featuring a planar indeno[1,2-b]thiophene as the π-linker of a bridging unit for dye-sensitized solar cells (DSSCs) was synthesized. The sensitizer had a strong molar absorption coefficient and a red-shifted absorption band compared with JK-305, which resulted in a significant increase in the short-circuit photocurrent density. We incorporated a highly congested bulky amino group into the 2',4'-dihexyloxybiphenyl-4-yl moiety, an electron donor, to diminish the charge recombination and to prevent aggregation of the sensitizer. Under standard AM 1.5G solar conditions, JK-306-sensitized cells in the presence of co-adsorbents chenodeoxycholic acid (CDCA) and 4-[bis(9,9-dimethyl-9H-fluoren-2-yl)amino]benzoic acid (HC-A), which afforded an overall conversion efficiency of 8.37% and 8.52%, respectively. Upon changing the I(-) /I3 (-) electrolyte to the Co(II) /Co(III) redox couple, the cell gave rise to a significantly improved conversion efficiency of 10.02% with the multifunctional HC-A, which is one of the highest values reported for DSSCs with a cobalt-based electrolyte. Furthermore, the JK-306-based solar cell with a polymer gel electrolyte revealed a high conversion efficiency of 7.61%, which is one of the highest values for cells based on organic sensitizers.

The impact of an indeno[1,2-b]thiophene spacer on dye-sensitized solar cell performances of cyclic thiourea functionalized organic sensitizers

“…The conversion efficiency of JK-314 is comparable to that of JK-306, (E)-3-{5 0 -{4-[bis(2 0 ,4 0 -dihexyloxybiphenyl-4-yl)amino] phenyl}-2,2 0 -bithioph-ene-5-yl}-2-cyanoacrylic acid, based DSSCs (8.52%, J sc ¼ 16.14 mA cm À2 , V oc ¼ 0.75 V, FF ¼ 0.71). 13 As shown in Fig. 4, J sc values of JK-314 increased dramatically relative to that of JK-313.…”

“…1,3-Dihexyl-5iodo-1H-benzo[d]imidazol-2(3H)-one was prepared according to the literature procedure. 7 1 H and 13 C NMR spectra were recorded on a Varian Mercury 300 spectrometer. Chemical shis d were calibrated against TMS as an internal standard.…”

“…The absorption spectrum of JK-313 displays two intense bands at 354 nm (3 ¼ 37 200 dm 3 mol À1 cm À1 ) and 460 nm (3 ¼ 20 600 dm 3 mol À1 cm À1 ), which are due to the p-p* transitions of the conjugated molecule. 6,13 Under the same conditions, JK-314 that contains the indeno [1,2-b]thiophene spacer exhibits red-shied absorption bands at 361 nm (3 ¼ 63 000 dm 3 mol À1 cm À1 ) and at 482 nm (3 ¼ 40 300 dm 3 mol À1 cm À1 ) as compared to the JK-313 dye. In addition, absorption of JK-314 at longer wavelength is remarkably red-shied (ca.…”

Graphene Nanoplatelets Doped with N at its Edges as Metal‐Free Cathodes for Organic Dye‐Sensitized Solar Cells

“…Thus, it is reasonable to conclude that an NGnP electrode in a Co(bpy) 3 2+/3+ medium has better electrochemical stability under prolonged cycling potential than a Pt electrode. On the basis of the in-depth evaluation of the NGnP and Pt CEs, the electrocatalytic activities of the NGnP CEs in actual organic DSSC devices were observed with the Co(bpy) 3 2+/3+ redox couple using a JK-306 sensitizer [ 45 ] and a multi-functional co-adsorbent HC-A (SGT-301, see SI). [46][47][48][49] The current-voltage characteristics of the DSSCs with the Pt and NGnP5 CEs are shown in Figure 4 a, and again results for the other NGnP samples are in the SI ( Figure S12).…”

The Hagfeldt Donor and Use of Next‐Generation Bulky Donor Designs in Dye‐Sensitized Solar Cells

“…For an original report with yields in the figure see this reference . For additional example reports using the same route see these references . THF is tetrahydrofuran.…”