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First Report of Chenodeoxycholic Acid–Substituted Dyes Improving the Dye Monolayer Quality in Dye‐Sensitized Solar Cells
Author(s) -
Buene Audun F.,
Almenningen David M.,
Hagfeldt Anders,
Gautun Odd R.,
Hoff Bård H.
Publication year - 2020
Publication title -
solar rrl
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.544
H-Index - 37
ISSN - 2367-198X
DOI - 10.1002/solr.201900569
Subject(s) - chenodeoxycholic acid , dye sensitized solar cell , monolayer , moiety , electrolyte , chemistry , electrochemistry , photochemistry , open circuit voltage , organic dye , energy conversion efficiency , materials science , chemical engineering , voltage , nanotechnology , organic chemistry , optoelectronics , electrode , cholesterol , biochemistry , physics , quantum mechanics , engineering
Chenodeoxycholic acid (CDCA) is the most used antiaggregation additive in dye‐sensitized solar cells since its introduction to the field in 1993. However, effective suppression of dye aggregation comes at the cost of reduced dye loading, a lower open‐circuit voltage, and limited control of dye/additive distribution when cosensitizing with free CDCA. To combat this, herein, a novel dye design concept that uses the covalent attachment of a CDCA moiety to triarylamine sensitizers is reported. The CDCA substituents do not affect the photophysical or electrochemical properties of the sensitizers but have a positive effect on the photovoltaic performance with [Cu +/2+ (tmby) 2 ](TFSI) 1/2 electrolyte (tmby = 4,4′,6,6′‐tetramethyl‐2,2′‐bipyridine, TFSI = bis(trifluoromethanesulfonyl)imide). By ensuring a one‐to‐one ratio of dye and CDCA, paired with isotropic distributions of each component, this approach results in a higher‐quality dye monolayer. Compared with the reference system, the novel approach reported herein gives a higher open‐circuit voltage and power conversion efficiency (PCE). The best device is fabricated with the dye C 6 –CDCA, delivering a PCE of 6.84% (8 μm TiO 2 , 1 m m CDCA, J SC = 8.64 mA cm −2 , V OC = 1007 mV, and FF = 0.77).