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Thiocyanate‐Free Ruthenium(II) Sensitizers for Dye‐Sensitized Solar Cells Based on the Cobalt Redox Couple
Author(s) -
Wu KuanLin,
Clifford John N.,
Wang ShengWei,
Aswani Yella,
Palomares Emilio,
Lobello Maria Grazia,
Mosconi Edoardo,
De Angelis Filippo,
Ku WanPing,
Chi Yun,
Nazeeruddin Mohammad K.,
Grätzel Michael
Publication year - 2014
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201402030
Subject(s) - thiocyanate , ruthenium , dye sensitized solar cell , electrolyte , chemistry , photochemistry , substituent , bipyridine , cobalt , materials science , inorganic chemistry , medicinal chemistry , electrode , crystallography , catalysis , organic chemistry , crystal structure
Two thiocyanate‐free ruthenium(II) sensitizers, TFRS‐41 and TFRS‐42 , with distinctive dialkoxyphenyl thienyl substituents were successfully prepared and tested for potential applications in making dye‐sensitized solar cells (DSCs). Subsequent device fabrication was conducted by using a [Co(bpy) 3 ] 2+/3+ ‐based (bpy=2,2′‐bipyridine) electrolyte, for which the best performance data, namely, J SC =13.11 mA cm −2 , V OC =862 mV, fill factor=0.771, and η =8.71 %, were recorded for the sensitizer TFRS‐42 with a 2,6‐dialkoxyphenyl substituent under AM 1.5G irradiation. The markedly higher V oc value was confirmed by the longer electron lifetime revealed in transient photovoltage (TPV) measurements versus the TFRS‐1 sensitizer. In addition, DFT calculation and detailed first‐principles computational analysis were conducted to provide a rationale for the observed trends in their photovoltaic performances and electron lifetimes, with reference to different performances exhibited by three thiocyanate‐free sensitizers, TFRS‐1 , TFRS‐41 and TFRS‐42 , versus Z907 reference. Through the proper control of peripheral substituents, the thiocyanate‐free ruthenium(II)‐based DSC sensitizers can positively influence the performances of DSCs, with better light‐harvesting capability and suppressed charge recombination, for DSC cells fabricated by using a [Co(bpy) 3 ] 2+/3+ ‐based electrolyte.