Molecular engineering of simple phenothiazine-based dyes to modulate dye aggregation, charge recombination, and dye regeneration in highly efficient dye-sensitized solar cells.

Citation data:

Chemistry (Weinheim an der Bergstrasse, Germany), ISSN: 1521-3765, Vol: 20, Issue: 21, Page: 6300-8

Publication Year:
2014
Usage 6
Abstract Views 6
Captures 26
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Citations 58
Citation Indexes 58
Repository URL:
https://repository.hkbu.edu.hk/hkbu_staff_publication/1461
PMID:
24715494
DOI:
10.1002/chem.201304897
Author(s):
Hua, Yong; Chang, Shuai; He, Jian; Zhang, Caishun; Zhao, Jianzhang; Chen, Tao; Wong, Wai-Yeung; Wong, Wai-Kwok; Zhu, Xunjin
Publisher(s):
Wiley; Wiley-VCH Verlag
Tags:
Chemistry; aggregation; charge recombination; dyes/pigments; phenothiazine; solar cells
article description
A series of simple phenothiazine-based dyes, namely, TP, EP, TTP, ETP, and EEP have been developed, in which the thiophene (T), ethylenedioxythiophene (E), their dimers, and mixtures are present to modulate dye aggregation, charge recombination, and dye regeneration for highly efficient dye-sensitized solar cell (DSSC) applications. Devices sensitized by the dyes TP and TTP display high power conversion efficiencies (PCEs) of 8.07 (Jsc = 15.2 mA cm(-2), Voc =0.783 V, fill factor (FF) = 0.679) and 7.87 % (Jsc = 16.1 mA cm(-2), Voc = 0.717 V, FF = 0.681), respectively; these were measured under simulated AM 1.5 sunlight in conjunction with the I(-)/I3(-) redox couple. By replacing the T group with the E unit, EP-based DSSCs had a slightly lower PCE of 7.98 % with a higher short-circuit photocurrent (Jsc) of 16.7 mA cm(-2). The dye ETP, with a mixture of E and T, had an even lower PCE of 5.62 %. Specifically, the cell based on the dye EEP, with a dimer of E, had inferior Jsc and Voc values and corresponded to the lowest PCE of 2.24 %. The results indicate that the photovoltaic performance can be finely modulated through structural engineering of the dyes. The selection of T analogues as donors can not only modulate light absorption and energy levels, but also have an impact on dye aggregation and interfacial charge recombination of electrons at the interface of titania, electrolytes, and/or oxidized dye molecules; this was demonstrated through DFT calculations, electrochemical impedance analysis, and transient photovoltage studies.