Molecular Design and Performance of Hydroxylpyridium Sensitizers for Dye-Sensitized Solar Cells

Abstract

Four hydroxylpyridium organic dyes were synthesized and applied in dye-sensitized solar cells (DSSCs). Hydroxylpyridium was introduced as an electron acceptor in donor-π-conjugated bridge-acceptor (D-π-A) system. The traditional anchoring groups, such as the carboxyl group, were replaced by hydroxyl group. It was found that the existence of the hydroxylpyridium exhibits a large effect on the absorption spectra of dyes JH401-JH404. For JH series of dyes, hexylthiophene was employed as the π-conjugated bridge, and triphenylamine, phenothiazine, and their derivatives were used as the electron donor. The performances of the dyes with different structure were investigated by photophysical, photovoltaic, and electrochemical methods. When applied in the DSSCs, the sensitizer JH401 yields the best efficiency, 2.6% (Jsc = 6.35 mA/cm(2), Voc = 605 mV, FF = 67.6%) under 100 mW/cm(2) light illumination. Its maximum incident photon-to-current conversion efficiency (IPCE) is 80% at 440 nm light wavelength, which is the highest IPCE value achieved with hydroxyl group adsorbent organic dyes so far.

Pyridomethene–BF2 complex/phenothiazine hybrid sensitizer with high molar extinction coefficient for efficient, sensitized solar cells

“…7 and S3). [51][52][53] The second oxidation of dyes K1-K8 occurred upon the removal of an electron from the pyridomethene-BF 2 complex and it is consistent with the oxidation potential of P3. 8.…”

Pyridine‐N‐Oxide 2‐Carboxylic Acid: An Acceptor Group for Organic Sensitizers with Enhanced Anchoring Stability in Dye‐Sensitized Solar Cells

“…[15] Alkylpyridinium salts featuring either a carboxylic acid or a hydroxyl group as the anchors were described by Sun and Ooyama and their respective co-workers. [16][17][18] Finally, a new kind of sensitizer that has a pyiridine-N-oxide anchoring moiety was also recently introduced. [19] Although some of the compounds prepared in those studies provide good power-conversion efficiencies, their photovoltaic performances were only rarely compared with those of compounds bearing the classic cyanoacrylic acid acceptor.…”

Design and synthesis of organic sensitizers with enhanced anchoring stability in dye-sensitized solar cells

“…It is known, for instance, that alkylation of the nitrogen atom of the pyridine ring might influence the dyes photophysical properties [23,25]. Indeed, two dyes with the same structure of DF13A,B,C, but with a m-carboxyl-N-methylpyridinium (TJ101) and a N-methylcarboxylpyridinium salt (TJ102) as acceptor/anchoring groups, were reported ( Fig.…”

“…Moreover, to improve the electron withdrawing ability of the acceptor, a 2-cyanopyridine group has also been introduced [22], which was reported to bind TiO 2 surface via coordination of Lewis acidic titanium sites by the pyridine nitrogen. Carboxomethyl-and hydroxymetyhyl pyridinium salts were also described [23][24][25][26]. All these works revealed the pyridyl groups as a very promising anchoring moiety and pointed out how the binding mode on the TiO 2 surface could be affected by control of the basicity and electron density of the pyridine group.…”