TY - JOUR
T1 - Effects of ω-guanidinoalkyl acids as coadsorbents in dye-sensitized solar cells
AU - Zhang, Zhipan
AU - Evans, Nick
AU - Zakeeruddin, Shaik M.
AU - Humphry-Baker, Robin
AU - Grätzel, Michael
PY - 2007/1/11
Y1 - 2007/1/11
N2 - Dye-sensitized solar cells (DSCs) based on nanocrystalline TiO2 have been fabricated with an amphiphilic ruthenium sensitizer NaRu(2,2′-bipyridine-4-carboxylic acid-4′-carboxylate)(4,4′- dinonyl-2,2′-bipyridine)-(NCS)2, coded as Z-907, and a series of ω-guanidinoalkyl acids as coadsorbents. The addition of guanidinoalkyl acids as coadsorbents increased the open-circuit voltage of the DSCs and had no adverse effect on the photocurrent if an appropriate amount was used. Phototransient measurements showed that the addition of these guanidino coadsorbents slowed down the charge recombination and that the increase in the open-circuit voltage was due to suppression of the recombination or an upward shift of the TiO2 band-edge to negative potentials. Thus, for the first time, a class of coadsorbents has been demonstrated to not only shield the surface electrons against recombination but also to shift the band edge to negative potentials, which is essential for future improvements in the performance of DSCs.
AB - Dye-sensitized solar cells (DSCs) based on nanocrystalline TiO2 have been fabricated with an amphiphilic ruthenium sensitizer NaRu(2,2′-bipyridine-4-carboxylic acid-4′-carboxylate)(4,4′- dinonyl-2,2′-bipyridine)-(NCS)2, coded as Z-907, and a series of ω-guanidinoalkyl acids as coadsorbents. The addition of guanidinoalkyl acids as coadsorbents increased the open-circuit voltage of the DSCs and had no adverse effect on the photocurrent if an appropriate amount was used. Phototransient measurements showed that the addition of these guanidino coadsorbents slowed down the charge recombination and that the increase in the open-circuit voltage was due to suppression of the recombination or an upward shift of the TiO2 band-edge to negative potentials. Thus, for the first time, a class of coadsorbents has been demonstrated to not only shield the surface electrons against recombination but also to shift the band edge to negative potentials, which is essential for future improvements in the performance of DSCs.
UR - https://www.scopus.com/pages/publications/33847629987
U2 - 10.1021/jp0648745
DO - 10.1021/jp0648745
M3 - Article
AN - SCOPUS:33847629987
SN - 1932-7447
VL - 111
SP - 398
EP - 403
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 1
ER -