Abstract
Guanidine nitrate (GuNO3) was introduced as an additive in I-/I3--based electrolyte to investigate its photoelectrochemical effects on dye-sensitized solar cells (DSSCs). GuNO3 induced the enhancement of the power conversion efficiency (PCE) up to ca. 21% by increasing both the photocurrent density and the open circuit voltage (Voc) of the DSSCs relative to that without additives. Meanwhile the adsorption of guanidinium cation (Gu+) induced a positive shift in the conduction band edge of the TiO2 nanoparticles (ECB,TiO2), toward electrochemical potentials by up to ∼110 mV, the presence of NO3- instead of SCN- in the electrolyte resulted in the shift in ECB,TiO2 in the opposite direction by up to ca. 40 mV, which corresponded to an additional increase in the Voc up to ca. 30 mV in the DSSCs with GuNO3 relative to that with GuSCN. The use of GuNO3 instead of GuSCN as an additive improved the PCE of DSSCs by up to ca. 6% owing to the relatively high values of Voc and the significant increase of the fill factor (FF) by enhancement of ionic conductivity of electrolyte.
Original language | English |
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Pages (from-to) | 151-157 |
Number of pages | 7 |
Journal | Electrochimica Acta |
Volume | 201 |
DOIs | |
State | Published - 20 May 2016 |
Keywords
- conduction band edge of TiO
- Dye-sensitized solar cells
- electrolyte
- guanidine nitrate
- open circuit voltage