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Influence of electrolyte co-additives on the performance of dye-sensitized solar cells.

Stergiopoulos T, Rozi E, Karagianni CS, Falaras P - Nanoscale Res Lett (2011)

Bottom Line: The presence of specific chemical additives in the redox electrolyte results in an efficient increase of the photovoltaic performance of dye-sensitized solar cells (DSCs).The most effective additives are 4-tert-butylpyridine (TBP), N-methylbenzimidazole (NMBI) and guanidinium thiocyanate (GuNCS) that are adsorbed onto the photoelectrode/electrolyte interface, thus shifting the semiconductor's conduction band edge and preventing recombination with triiodides.Further addition of GuNCS in the optimized electrolytic media causes significant synergistic effects, the action of GuNCS being strongly influenced by the nature of the corresponding co-additive.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Physical Chemistry, NCSR "Demokritos", Aghia Paraskevi Attikis, Athens 15310, Greece. stergt@chem.demokritos.gr.

ABSTRACT
The presence of specific chemical additives in the redox electrolyte results in an efficient increase of the photovoltaic performance of dye-sensitized solar cells (DSCs). The most effective additives are 4-tert-butylpyridine (TBP), N-methylbenzimidazole (NMBI) and guanidinium thiocyanate (GuNCS) that are adsorbed onto the photoelectrode/electrolyte interface, thus shifting the semiconductor's conduction band edge and preventing recombination with triiodides. In a comparative work, we investigated in detail the action of TBP and NMBI additives in ionic liquid-based redox electrolytes with varying iodine concentrations, in order to extract the optimum additive/I2 ratio for each system. Different optimum additive/I2 ratios were determined for TBP and NMBI, despite the fact that both generally work in a similar way. Further addition of GuNCS in the optimized electrolytic media causes significant synergistic effects, the action of GuNCS being strongly influenced by the nature of the corresponding co-additive. Under the best operation conditions, power conversion efficiencies as high as 8% were obtained.

No MeSH data available.


Related in: MedlinePlus

Additive effects on electron recombination and transport properties for DSCs using optimum electrolytes. (a) Electron lifetimes (τη) versus photovoltage (Voc) and (b) electron diffusion coefficients (De) versus the short-circuit photocurrent (Jsc), for PMII-0.02 M I2-PC electrolyte without additive as well as in the presence of TBP additive and TBP/GuNCS co-additives. (c) Electron lifetimes (τη) versus Voc, and (d) electron diffusion coefficients (De) versus Jsc, for PMII-0.08 M I2-PC electrolytes without additive, with NMBI and with NMBI-GuNCS co-additives.
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Figure 3: Additive effects on electron recombination and transport properties for DSCs using optimum electrolytes. (a) Electron lifetimes (τη) versus photovoltage (Voc) and (b) electron diffusion coefficients (De) versus the short-circuit photocurrent (Jsc), for PMII-0.02 M I2-PC electrolyte without additive as well as in the presence of TBP additive and TBP/GuNCS co-additives. (c) Electron lifetimes (τη) versus Voc, and (d) electron diffusion coefficients (De) versus Jsc, for PMII-0.08 M I2-PC electrolytes without additive, with NMBI and with NMBI-GuNCS co-additives.

Mentions: The DSCs presenting the optimum efficiency have been then used as reference cells for further experiments. To this end, GuNCS was added in the electrolytes already containing the TBP or NMBI additives to significantly increase the Jsc (and slightly the Voc) of the cells. The J-V curves of the cells were drawn in Figure 2 while a comparative evaluation of the results is summarized on Tables 1 and 2. Additionally, Intensity Modulated Voltage Spectroscopy (IMVS) and Intensity Modulated Photocurrent Spectroscopy (IMPS) were used to extract valuable information about recombination kinetics under open-circuit and charge transport properties at short-circuit conditions, respectively [26]. Figure 3a, c presents the plots of the electron lifetime (τn) versus the photovoltage while Figure 3b, d displays the plots of the electron diffusion coefficients (De-) versus the photocurrent.


Influence of electrolyte co-additives on the performance of dye-sensitized solar cells.

Stergiopoulos T, Rozi E, Karagianni CS, Falaras P - Nanoscale Res Lett (2011)

Additive effects on electron recombination and transport properties for DSCs using optimum electrolytes. (a) Electron lifetimes (τη) versus photovoltage (Voc) and (b) electron diffusion coefficients (De) versus the short-circuit photocurrent (Jsc), for PMII-0.02 M I2-PC electrolyte without additive as well as in the presence of TBP additive and TBP/GuNCS co-additives. (c) Electron lifetimes (τη) versus Voc, and (d) electron diffusion coefficients (De) versus Jsc, for PMII-0.08 M I2-PC electrolytes without additive, with NMBI and with NMBI-GuNCS co-additives.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211393&req=5

Figure 3: Additive effects on electron recombination and transport properties for DSCs using optimum electrolytes. (a) Electron lifetimes (τη) versus photovoltage (Voc) and (b) electron diffusion coefficients (De) versus the short-circuit photocurrent (Jsc), for PMII-0.02 M I2-PC electrolyte without additive as well as in the presence of TBP additive and TBP/GuNCS co-additives. (c) Electron lifetimes (τη) versus Voc, and (d) electron diffusion coefficients (De) versus Jsc, for PMII-0.08 M I2-PC electrolytes without additive, with NMBI and with NMBI-GuNCS co-additives.
Mentions: The DSCs presenting the optimum efficiency have been then used as reference cells for further experiments. To this end, GuNCS was added in the electrolytes already containing the TBP or NMBI additives to significantly increase the Jsc (and slightly the Voc) of the cells. The J-V curves of the cells were drawn in Figure 2 while a comparative evaluation of the results is summarized on Tables 1 and 2. Additionally, Intensity Modulated Voltage Spectroscopy (IMVS) and Intensity Modulated Photocurrent Spectroscopy (IMPS) were used to extract valuable information about recombination kinetics under open-circuit and charge transport properties at short-circuit conditions, respectively [26]. Figure 3a, c presents the plots of the electron lifetime (τn) versus the photovoltage while Figure 3b, d displays the plots of the electron diffusion coefficients (De-) versus the photocurrent.

Bottom Line: The presence of specific chemical additives in the redox electrolyte results in an efficient increase of the photovoltaic performance of dye-sensitized solar cells (DSCs).The most effective additives are 4-tert-butylpyridine (TBP), N-methylbenzimidazole (NMBI) and guanidinium thiocyanate (GuNCS) that are adsorbed onto the photoelectrode/electrolyte interface, thus shifting the semiconductor's conduction band edge and preventing recombination with triiodides.Further addition of GuNCS in the optimized electrolytic media causes significant synergistic effects, the action of GuNCS being strongly influenced by the nature of the corresponding co-additive.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Physical Chemistry, NCSR "Demokritos", Aghia Paraskevi Attikis, Athens 15310, Greece. stergt@chem.demokritos.gr.

ABSTRACT
The presence of specific chemical additives in the redox electrolyte results in an efficient increase of the photovoltaic performance of dye-sensitized solar cells (DSCs). The most effective additives are 4-tert-butylpyridine (TBP), N-methylbenzimidazole (NMBI) and guanidinium thiocyanate (GuNCS) that are adsorbed onto the photoelectrode/electrolyte interface, thus shifting the semiconductor's conduction band edge and preventing recombination with triiodides. In a comparative work, we investigated in detail the action of TBP and NMBI additives in ionic liquid-based redox electrolytes with varying iodine concentrations, in order to extract the optimum additive/I2 ratio for each system. Different optimum additive/I2 ratios were determined for TBP and NMBI, despite the fact that both generally work in a similar way. Further addition of GuNCS in the optimized electrolytic media causes significant synergistic effects, the action of GuNCS being strongly influenced by the nature of the corresponding co-additive. Under the best operation conditions, power conversion efficiencies as high as 8% were obtained.

No MeSH data available.


Related in: MedlinePlus