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ZnO Nanostructures for Dye‐Sensitized Solar Cells Using the TEMPO + /TEMPO Redox Mediator and Ruthenium(II) Photosensitizers with 1,2,3‐Triazole‐Derived Ligands
Author(s) -
Wahyuono Ruri Agung,
Schulze Benjamin,
Rusu Mihai,
Wächtler Maria,
Dellith Jan,
Seyring Martin,
Rettenmayr Markus,
Plentz Jonathan,
Ignaszak Anna,
Schubert Ulrich S.,
Dietzek Benjamin
Publication year - 2016
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.201600377
Subject(s) - dye sensitized solar cell , ruthenium , electrolyte , chemistry , redox , photochemistry , energy conversion efficiency , inorganic chemistry , materials science , organic chemistry , electrode , catalysis , optoelectronics
A series of thiocyanate‐free bis(tridentate) ruthenium(II) complexes incorporating 1,2,3‐triazole‐derived NNN‐, NCN‐, and CNC‐coordinating ligands has been employed for sensitizing ZnO photoanodes for dye‐sensitized solar cells (DSSCs). Additionally, the first use of the TEMPO + /TEMPO (2,2,6,6‐tetramethyl‐piperidine‐1‐oxyl) redox mediator as a surrogate for the I 3 − /I − redox couple in ZnO nanostructured DSSCs is presented. Compared with I 3 − /I − ‐based electrolytes, shorter charge lifetimes and diffusion lengths were determined for the TEMPO + /TEMPO‐based electrolyte. Nonetheless, similar power conversion efficiencies (PCEs) were achieved with both electrolytes for the RuNCN and RuCNC complexes, whereas higher PCEs are enabled by the iodine‐free electrolyte in case of RuNNN. The combination of the molecular sensitizers and the TEMPO‐based electrolyte exhibits relatively high external quantum efficiency (EQE) and promising PCEs, ranging from 4.48 to 1.47 %, which are—in part—comparable to that of ZnO‐DSSCs with the benchmark N749 black dye. The TEMPO‐based electrolyte also exhibits less absorption compared with its I 3 − /I − counterpart, a favorable feature for enhancing the light harvesting ability of the photoanode. Furthermore, the results show the effect of the dye‐sensitization procedure on the PCE values: The use of ethanol as the solvent compared with methanol increases the DSSC's efficiency, which is attributed to improved chemisorption of the sensitizer onto the ZnO surface.