TY - JOUR
T1 - Engineering of thiocyanate-free Ru(II) sensitizers for high efficiency dye-sensitized solar cells
AU - Wang, Sheng-Wei
AU - Wu, Kuan-Lin
AU - Ghadiri, Elham
AU - Lobello, Maria Grazia
AU - Ho, Shu-Te
AU - Chi, Yun
AU - Moser, Jacques-E.
AU - De Angelis, Filippo
AU - Grätzel, Michael
AU - Nazeeruddin, Mohammad K.
PY - 2013/5/7
Y1 - 2013/5/7
N2 - We synthesized a series of Ru(II) metal complexes TFRS-1, -2, -4, -21, -22 and -24 with a single 4,4′-dicarboxylic acid-2,2′-bipyridine together with two functionalized pyridyl azolate ancillary ligands consisting of pyrazolate or triazolate groups. Both photophysical measurements and DFT/TDDFT calculations were conducted to gain insight into their electronic and optical properties. The triazolate series of sensitizers TFRS-21, -22 and -24 showed an enlarged optical band gap with respect to their pyrazolate counterparts TFRS-1, -2 and -4. When employed in dye sensitized solar cells (DSCs), the triazolate sensitizers show slightly inferior JSC values due to the poor incident photon-to-current conversion efficiencies recorded compared to the pyrazolate series. Moreover, the endowed 5-(hexylthio)thiophen-2-yl substituents exert a notable hyperchromic effect and bathochromic shift in the absorption spectra, which then improves the short circuit current JSC to 18.7 and 15.5 mA cm−2 and the overall conversion efficiency to η = 10.2% and 8.25% for TFRS-4 and TFRS-24, respectively. For the evaluation of VOC, transient photocurrent and photovoltage decay measurements were carried out to compare the rates of interfacial recombination of electrons from the TiO2 conduction band to electrolyte.
AB - We synthesized a series of Ru(II) metal complexes TFRS-1, -2, -4, -21, -22 and -24 with a single 4,4′-dicarboxylic acid-2,2′-bipyridine together with two functionalized pyridyl azolate ancillary ligands consisting of pyrazolate or triazolate groups. Both photophysical measurements and DFT/TDDFT calculations were conducted to gain insight into their electronic and optical properties. The triazolate series of sensitizers TFRS-21, -22 and -24 showed an enlarged optical band gap with respect to their pyrazolate counterparts TFRS-1, -2 and -4. When employed in dye sensitized solar cells (DSCs), the triazolate sensitizers show slightly inferior JSC values due to the poor incident photon-to-current conversion efficiencies recorded compared to the pyrazolate series. Moreover, the endowed 5-(hexylthio)thiophen-2-yl substituents exert a notable hyperchromic effect and bathochromic shift in the absorption spectra, which then improves the short circuit current JSC to 18.7 and 15.5 mA cm−2 and the overall conversion efficiency to η = 10.2% and 8.25% for TFRS-4 and TFRS-24, respectively. For the evaluation of VOC, transient photocurrent and photovoltage decay measurements were carried out to compare the rates of interfacial recombination of electrons from the TiO2 conduction band to electrolyte.
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U2 - 10.1039/c3sc50399b
DO - 10.1039/c3sc50399b
M3 - RGC 21 - Publication in refereed journal
SN - 2041-6520
VL - 4
SP - 2423
EP - 2433
JO - Chemical Science
JF - Chemical Science
IS - 6
ER -
