Efficient light-scattering functionalized TiO2 photoanodes modified with cyanobiphenyl-based benzimidazole for dye-sensitized solar cells with additive-free electrolytes

Zhao, Jie; Sun, Baoquan; Qiu, Lihua; Caocen, Huizi; Li, Qing; Chen, Xiaojian; Yan, Feng

doi:10.1039/c2jm32607h

Cited by 33 publications

(22 citation statements)

References 55 publications

(68 reference statements)

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“…The ηcoll value can be conjectured from the lifetime of the electrons photo-injected into the TiO2 valence band; that is, a prolonged electron lifetime induces an increase in ηcoll. We conducted EIS analysis to estimate the electron lifetime and charge transport of the devices with the pristine and surface-modified photoanodes [28][29][30]. As shown in the Bode phase plots of the EIS spectra ( Figure 8) measured under illumination, the peak frequency (fmax) of the device with the Na2S(5)-TiO2/FTO was obtained as 26.94 Hz, which was identical to that of the reference device.…”

Section: Effects Of Surface Modification On J Scmentioning

confidence: 80%

“…As shown in the Bode phase plots of the EIS spectra (Figure 8) measured under illumination, the peak frequency (f max ) of the device with the Na 2 S(5)-TiO 2 /FTO was obtained as 26.94 Hz, which was identical to that of the reference device. The electron lifetime (τ n ) estimated using the equation [29,30] τ n = 1/2πf max ,…”

Section: Effects Of Surface Modification On J Scmentioning

confidence: 99%

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Enhanced Power Conversion Efficiency of Dye-Sensitized Solar Cells by Band Edge Shift of TiO2 Photoanode

et al. 2020

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By simple soaking titanium dioxide (TiO2) films in an aqueous Na2S solution, we could prepare surface-modified photoanodes for application to dye-sensitized solar cells (DSSCs). An improvement in both the open-circuit voltage (Voc) and the fill factor (FF) was observed in the DSSC with the 5 min-soaked photoanode, compared with those of the control cell without any modification. The UV–visible absorbance spectra, UPS valence band spectra, and dark current measurements revealed that the Na2S modification led to the formation of anions on the TiO2 surface, and thereby shifted the conduction band edge of TiO2 in the negative (upward) direction, inducing an increase of 29 mV in the Voc. It was also found that the increased FF value in the surface-treated device was attributed to an elevation in the shunt resistance.

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Section: Effects Of Surface Modification On J Scmentioning

confidence: 80%

Section: Effects Of Surface Modification On J Scmentioning

confidence: 99%

Enhanced Power Conversion Efficiency of Dye-Sensitized Solar Cells by Band Edge Shift of TiO2 Photoanode

et al. 2020

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“…The larger value of R REC indicates the resistance to recombination while using P2 as barrier layer. [ 27 ] The increased resistance to recombination is due to two reasons (i) the electron transfer from the TiO 2 to P2 is not possible due to high lying LUMO of P2 and (ii) the electron transfer from the polymer to redox electrolyte is not possible due to the low lying HOMO of the polymer. Thus, the electron transfer from the TiO 2 to the iodolyte is not possible while P2 is used as barrier layer.…”

Section: Resultsmentioning

confidence: 99%

Band Edge Modulated Polymer Layer to Decrease Back Electron Transfer and Increase Efficiency in Sensitized Solar Cells

Arulkashmir

Sudhakar

Krishnamoorthy

2016

Advanced Energy Materials

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time scale of electron transport from TiO 2 to conducting glass is in milliseconds. [ 7 ] Thus, the increased residence time of the electron in TiO 2 increases the possibility of BeT with the holes in either dyes or electrolyte. In fact, the recombination of electron in TiO 2 with that of the holes in electrolytes has been found to be one of the major causes of decreased DSSC efficiency. Thus, suppression of BeT process is an effective way to improve the DSSC effi ciency. However, the approach should not affect the electron injection from the dyes to the TiO 2 . One of the approaches to suppress the BeT process is the addition of additives in the redox electrolytes. [ 8,9 ] These additives adsorb on the TiO 2 and decrease the BeT. [ 10 ] Modifi cation of TiO 2 by alkyl silane is another approach to suppress the BeT. [11][12][13] Although these approaches increased the effi ciency of DSSC, the improvement is not very high because the layer thickness is not high. The attempt to use longer alkyl chain silanes with an objective of increasing the thickness did not signifi cantly alter the DSSC effi ciency due to the imperfect coverage of the TiO 2 surface. [ 14,15 ] Several inorganic oxide barrier layers such as Al 2 O 3 , HfO 2 , and In 2 O 3 have been explored as barrier layer. [16][17][18][19] These barrier layers were deposited before dye absorption either by chemical bath deposition or by atomic layer deposition. The insulating nature of these layers affects the charge injection process. Furthermore, the energy levels of the barrier layer also affect the electron transfer dynamics. [ 20 ] Organic polymers have been coated on top of TiO 2 in solid state dye sensitized solar cells with a different objective. An ion-ligating polymer with different ionization potential has been used to facilitate cascade electron transport. [ 21 ] Photo electropolymerized PEDOT was used as hole transport layer in a solid state dye sensitized solar cell without any other electrolyte. The effi ciencies of these cells were 5.6%. [ 22 ] Considering this, a barrier layer that does not affect electron transfer from LUMO of the dye to TiO 2 and electrolyte to the HOMO of the dye is desirable. It will be an added advantage, if the layer is prepared by solution process. Toward this objective, we have used semiconducting polymers with commensurate band edges to retard the BeT process ( Figure 1 a). The polymers with the structures shown in Figure 1 b were tested and found out that a polymer with a HOMO and LUMO levels at −5.8 and −3.1 eV, respectively, can improve the DSSC effi ciency by 22%. The effi ciency Recombination of charges residing in the TiO 2 and redox electrolyte is one of the factors affecting the effi ciency of dye sensitized solar cells (DSSCs). To circumvent this recombination, inorganic oxide barrier layers and organic silanes have been coated on TiO 2 /dyes. Due to the insulating nature of these layers, the effi ciency increase is not very impressive. Conducting polymers with different band edges are used to suppress the cha...

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“…Among these, benzimidazoles and benzoxazoles are more prominently found in natural products and commercially available drugs (Figure 1). [5] Furthermore, they have also been applied in dyes, [6] chemosensing, [7] and fluorescence. [5] Furthermore, they have also been applied in dyes, [6] chemosensing, [7] and fluorescence.…”

Section: Introductionmentioning

confidence: 99%

Construction of Benzimidazoles and Benzoxazoles through the Molybdenum‐Mediated Carbonylation of Aryl Halides

et al. 2015

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The facile and efficient one‐pot construction of benzimidazoles and benzoxazoles through the Mo(CO)6‐mediated carbonylation of aryl halides was examined. In the process, Mo(CO)6 acted as a convenient and safe solid source of carbon monoxide. A wide range of substrates were tolerated to provide the corresponding products in fair to good yields without the need of gaseous CO or palladium catalysts.

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Efficient light-scattering functionalized TiO2 photoanodes modified with cyanobiphenyl-based benzimidazole for dye-sensitized solar cells with additive-free electrolytes

Cited by 33 publications

References 55 publications

Enhanced Power Conversion Efficiency of Dye-Sensitized Solar Cells by Band Edge Shift of TiO2 Photoanode

Enhanced Power Conversion Efficiency of Dye-Sensitized Solar Cells by Band Edge Shift of TiO2 Photoanode

Band Edge Modulated Polymer Layer to Decrease Back Electron Transfer and Increase Efficiency in Sensitized Solar Cells

Construction of Benzimidazoles and Benzoxazoles through the Molybdenum‐Mediated Carbonylation of Aryl Halides

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