Organic dyes containing oligo-phenothiazine for dye-sensitized solar cells

Abstract

A series of organic dyes containing oligo-phenothiazine were synthesized and used effectively on the fabrication of dye-sensitized solar cells (DSSCs). In these compounds the phenothiazine moiety functions both as an electron donor and as a p-bridge. These materials exhibit considerably high values of open-circuit voltage (V oc ) ranging from 0.78-0.83 V under an AM1.5 solar condition (100 mW cm À2 ). Two kinds of substituents, i.e., hexyl and hexyloxyphenyl groups, were added onto the N(10) of phenothiazine for comparison. The best device displayed a short-circuit current (J sc ) of 14.3 mA cm À2 , an open-circuit voltage (V oc ) of 0.83 V, a fill factor (FF) of 0.65, corresponding to an overall conversion efficiency of 7.78%. Their photophysical properties were analyzed with the aid of a time-dependent density functional theory (TDDFT) model with the B3LYP functional. The electronic nature of the devices was further elucidated by using electrochemical impedance spectroscopy.

Significant improvement of phenothiazine organic dye-sensitized solar cell performance using dithiafulvenyl unit as additional donor

“…The reference dye C 6 PTZ was synthesized according to previous report [49]. The synthetic routes to the dyes WD14 and WD15 are shown in Scheme 2.…”

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

“…The dye sensitizer plays a crucial factor in the performance of DSSC, both on power conversion efficiency (η) as well as on device stability. Various kinds of organic dyes based on coumarin, 6 phenothiazine, [7][8][9][10] cyanine, 11 indoline, 12 triphenylamine, [13][14][15][16][17][18][19][20] derivatives have been shown to work effectively for DSSC. In contrast to metal complexes, organic dyes have been extensively explored in recent years due to their low cost, environmental friendliness, high molar absorption coefficient, tunable spectra, and others.…”

“…A high absorption coefficient in the visible wavelength will increase the value of shortcircuit current density (J sc ). 8,10 The structure of phenothiazine contains an electronrich heterocycle made with sulfur and nitrogen. However, rod-like molecules may magnify aggregate formation between molecules and facilitate the recombination of electrons with triiodide electrolyte.…”

Long‐Range π‐Conjugation in Phenothiazine‐containing Donor–Acceptor Dyes for Application in Dye‐Sensitized Solar Cells

“…Organic dyes containing oligo‐phenothiazine were used as both the electron donor and as the π‐conjugated spacer in sensitizers for DSC. It is additionally reported that long π‐bridges can adversely affect photovoltaic device performance . In this study we combine these concepts to systematically varied the π‐bridge length by introducing 0, 1, or 2 phenothiazine units between the donor and acceptor.…”