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NH3-treated WO3 as low-cost and efficient counter electrode for dye-sensitized solar cells.

Song D, Chen Z, Cui P, Li M, Zhao X, Li Y, Chu L - Nanoscale Res Lett (2015)

Bottom Line: Correspondingly, the power conversion efficiency (PCE) of the DSC is significantly increased from 0.9% for pristine WO3 CE to 5.9% for NH3-treated WO3 CE.In addition, it is also shown that NH3 treatment is more efficient than H2 or N2 treatment in enhancing the catalytic performance of WO3 CE.This work highlights the potential of NH3-treated WO3 for the application in DSCs and provides a facile method to get highly efficient and low-cost CEs from catalytic inert metal oxides.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, School of Renewable Energy, North China Electric Power University, No. 2 Beinong Rd, Changping, Beijing, 102206 China.

ABSTRACT
A novel low-cost and efficient counter electrode (CE) was obtained by treating catalytic inert tungsten trioxide (WO3) nanomaterial in NH3 atmosphere at elevated temperatures. The formation of tungsten oxynitride from WO3 after NH3 treatment, as evidenced by X-ray photoelectron spectroscopy and X-ray diffraction, increases the catalytic activity of the CE. Correspondingly, the power conversion efficiency (PCE) of the DSC is significantly increased from 0.9% for pristine WO3 CE to 5.9% for NH3-treated WO3 CE. The photovoltaic performance of DSC using NH3-treated WO3 CE is comparable to that of DSC using standard Pt CE (with a PCE of 6.0%). In addition, it is also shown that NH3 treatment is more efficient than H2 or N2 treatment in enhancing the catalytic performance of WO3 CE. This work highlights the potential of NH3-treated WO3 for the application in DSCs and provides a facile method to get highly efficient and low-cost CEs from catalytic inert metal oxides.

No MeSH data available.


Nyquist plots from symmetric cells with different counter electrodes. The inset shows the equivalent circuit of the symmetric cells.
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Fig4: Nyquist plots from symmetric cells with different counter electrodes. The inset shows the equivalent circuit of the symmetric cells.

Mentions: To study the kinetics of the catalytic property of the CEs, EIS was carried out on symmetric cells fabricated with two identical CEs. Nyquist plots from WO3, NH3-treated WO3, and standard Pt CEs are shown in Figure 4, and the equivalent circuit of the symmetric cells is shown in the inset of Figure 4. The high-frequency intercept at the real axis (Z′) represents the series resistance (RS). Two arcs can be seen in the Nyquist plots, which correspond to the charge transfer resistance (RCT) and the capacitance (CPE) at electrolyte/electrode interface (the left arc in the high-frequency region) and the Nernst diffusion impedance (ZN) of redox sites in the electrolyte (the right arc in the low-frequency region), respectively [3,10,12]. The simulated RCT of the NH3-treated WO3 CEs is 9.2 Ω, similar to that of the Pt electrode (9.3 Ω). In regard to the pristine WO3 CE, the electrocatalytic activity is lower according to its large RCT (>100 Ω). The simulated ZN of Pt CE is 4.7 Ω, while those of WO3 CE and NH3-treated WO3 CE are higher probably due to combination of the Nernst diffusion impedance and the porous diffusion impedance in the porous WO3-based CEs. Nevertheless, the similar RCT value of NH3-treated WO3 and standard Pt CE highlights the superior electrocatalytic activity of NH3-treated WO3 CE for the reduction of triiodide ions, which provides a crucial precondition for replacing the Pt CE with the NH3-treated WO3 CE in DSCs.Figure 4


NH3-treated WO3 as low-cost and efficient counter electrode for dye-sensitized solar cells.

Song D, Chen Z, Cui P, Li M, Zhao X, Li Y, Chu L - Nanoscale Res Lett (2015)

Nyquist plots from symmetric cells with different counter electrodes. The inset shows the equivalent circuit of the symmetric cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385038&req=5

Fig4: Nyquist plots from symmetric cells with different counter electrodes. The inset shows the equivalent circuit of the symmetric cells.
Mentions: To study the kinetics of the catalytic property of the CEs, EIS was carried out on symmetric cells fabricated with two identical CEs. Nyquist plots from WO3, NH3-treated WO3, and standard Pt CEs are shown in Figure 4, and the equivalent circuit of the symmetric cells is shown in the inset of Figure 4. The high-frequency intercept at the real axis (Z′) represents the series resistance (RS). Two arcs can be seen in the Nyquist plots, which correspond to the charge transfer resistance (RCT) and the capacitance (CPE) at electrolyte/electrode interface (the left arc in the high-frequency region) and the Nernst diffusion impedance (ZN) of redox sites in the electrolyte (the right arc in the low-frequency region), respectively [3,10,12]. The simulated RCT of the NH3-treated WO3 CEs is 9.2 Ω, similar to that of the Pt electrode (9.3 Ω). In regard to the pristine WO3 CE, the electrocatalytic activity is lower according to its large RCT (>100 Ω). The simulated ZN of Pt CE is 4.7 Ω, while those of WO3 CE and NH3-treated WO3 CE are higher probably due to combination of the Nernst diffusion impedance and the porous diffusion impedance in the porous WO3-based CEs. Nevertheless, the similar RCT value of NH3-treated WO3 and standard Pt CE highlights the superior electrocatalytic activity of NH3-treated WO3 CE for the reduction of triiodide ions, which provides a crucial precondition for replacing the Pt CE with the NH3-treated WO3 CE in DSCs.Figure 4

Bottom Line: Correspondingly, the power conversion efficiency (PCE) of the DSC is significantly increased from 0.9% for pristine WO3 CE to 5.9% for NH3-treated WO3 CE.In addition, it is also shown that NH3 treatment is more efficient than H2 or N2 treatment in enhancing the catalytic performance of WO3 CE.This work highlights the potential of NH3-treated WO3 for the application in DSCs and provides a facile method to get highly efficient and low-cost CEs from catalytic inert metal oxides.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, School of Renewable Energy, North China Electric Power University, No. 2 Beinong Rd, Changping, Beijing, 102206 China.

ABSTRACT
A novel low-cost and efficient counter electrode (CE) was obtained by treating catalytic inert tungsten trioxide (WO3) nanomaterial in NH3 atmosphere at elevated temperatures. The formation of tungsten oxynitride from WO3 after NH3 treatment, as evidenced by X-ray photoelectron spectroscopy and X-ray diffraction, increases the catalytic activity of the CE. Correspondingly, the power conversion efficiency (PCE) of the DSC is significantly increased from 0.9% for pristine WO3 CE to 5.9% for NH3-treated WO3 CE. The photovoltaic performance of DSC using NH3-treated WO3 CE is comparable to that of DSC using standard Pt CE (with a PCE of 6.0%). In addition, it is also shown that NH3 treatment is more efficient than H2 or N2 treatment in enhancing the catalytic performance of WO3 CE. This work highlights the potential of NH3-treated WO3 for the application in DSCs and provides a facile method to get highly efficient and low-cost CEs from catalytic inert metal oxides.

No MeSH data available.