The Influence of Charge Transport and Recombination on the Performance of Dye‐Sensitized Solar Cells

Wang, Mingkui; Chen, Peter; Humphry‐Baker, Robin; Zakeeruddin, Shaik M.; Grätzel, Michaël

doi:10.1002/cphc.200800708

Cited by 258 publications

(256 citation statements)

References 47 publications

(90 reference statements)

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“…Comparing devices A and B with device C, the V oc decreased with an increase in the concentration of the oxidized species in the electrolytes, because of the increase of the dark current. Interestingly, the J sc , V oc and FF values of device B with electrolyte II are 12.17 mA cm 22 , 656 mV and 0.63, respectively, which yield an overall powerconversion efficiency of 5.0%, higher than that of 4.0% reported previously for the corresponding device with an iodide-free, Co(III/II) complexes-based volatile electrolyte 18,19 . Changing the redox couple from T 2 /T 2 to I 3 2 /I 2 (with the same oxidized species concentration) in device F (Fig.…”

Section: Resultscontrasting

confidence: 53%

“…Previously, with a similar thick, double-layer TiO 2 film, we obtained an efficiency of over 9.5% using an optimized volatile I 3 2 /I 2 electrolyte 21,22 . As indicated in Fig.…”

Section: Resultsmentioning

confidence: 89%

“…We demonstrated previously 22 that the presence of different hole-transporting materials influences recombination between the oxidized redox couple and the photoinjected electrons in TiO 2 , and thus on the photovoltaic performance of the device (fabricated using volatile, low volatility or ionic liquid electrolytes). The charge-recombination kinetics and electron-diffusion dynamics in the DSC devices were derived using the methodology proposed /I 2 as the redox mediator.…”

Section: Resultsmentioning

confidence: 96%

“…2, blue curve). At a lower light intensity (10 mW cm 22 ), the efficiency of the device was as high as 8.1% (Table 1). The IPCE of device E is very high, greater than 60% in the spectral range from 400 to 640 nm with a maximum of 85% at 540 nm.…”

Section: Resultsmentioning

confidence: 99%

“…Dotted lines correspond to the dark-current measurement. Cells were tested using a metal mask with an aperture area of 0.158 cm 2 and measured under air mass 1.5 global (AM 1.5 G) (100 mW cm 22 ).…”

Section: Resultsmentioning

confidence: 99%

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An organic redox electrolyte to rival triiodide/iodide in dye-sensitized solar cells

et al. 2010

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Dye-sensitized solar cells (DSCs) have achieved impressive conversion efficiencies for solar energy of over 11% with an electrolyte that contains triiodide/iodide as a redox couple. Although triiodide/iodide redox couples work efficiently in DSCs, they suffer from two major disadvantages: electrolytes that contain triiodide/iodide corrode electrical contacts made of silver (which reduces the options for the scale up of DSCs to module size) and triiodide partially absorbs visible light. Here, we present a new disulfide/thiolate redox couple that has negligible absorption in the visible spectral range, a very attractive feature for flexible DSCs that use transparent conductors as current collectors. Using this novel, iodide-free redox electrolyte in conjunction with a sensitized heterojunction, we achieved an unprecedented efficiency of 6.4% under standard illumination test conditions. This novel redox couple offers a viable pathway to develop efficient DSCs with attractive properties for scale up and practical applications. Since the beginning of the 1990s much attention has been paid to alternative energy sources, in particular to photovoltaic solar energy 1,2 . DSCs (or Grätzel cells) currently attract considerable interest because of their high light-to-electricity conversion efficiencies, relatively easy fabrication procedures and low production cost 3 . The most common electrolyte in high-performance DSCs uses the triiodide/iodide (I 3 2 /I 2 ) redox couple 4-6 . Even though this redox couple works efficiently, it has disadvantages, such as the corrosion of silver-based current collectors and the partial absorption of visible light around 430 nm by the triiodide species 7 . Therefore, it is important to study alternative redox couples [8][9][10][11] , including p-type semiconductors 12 and solid-state, hole-transporting materials 13 . Electrolytes composed of a high molecular weight poly(ethylene oxide)-based copolymer in complex with an alkali metal polysulfide (M 2 S n ; redox couple S n 22 /S nþ1 22) or a caesium thiolate salt (redox couple disulfide/thiolate) are used successfully in all solid-state, electrochemical photovoltaic cells (n-CdSe|polymer redox electrolyte|ITO, where ITO represents the indium-tin-oxide conductive layer on the glass electrode) 14,15 . These studies encouraged us to introduce disulfide/thiolate (T 2 /T 2 ) molecules (instead of I 3 2 /I 2 ones) as redox mediators in DSC electrolytes. Results and discussionCharacterization of the DSC redox couple. The redox couple T 2 /T 2 , where T 2 represents the 5-mercapto-1-methyltetrazole ion and T 2 stands for its dimer (Fig. 1), was characterized electrochemically (Supplementary Fig. S1) and studied as an electrolyte for DSCs. The redox potential for T 2 /T 2 was found to be 0.485 V against a normal hydrogen electrode (NHE, Supplementary Fig. S1), which is close to that of the I 3 2 /I 2 redox couple (reported values range from 0.4 V to 0.53 V against NHE in organic solvents 16,17 ) used in a DSC. Delocalization of the negative charge fo...

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Section: Resultscontrasting

confidence: 53%

“…Previously, with a similar thick, double-layer TiO 2 film, we obtained an efficiency of over 9.5% using an optimized volatile I 3 2 /I 2 electrolyte 21,22 . As indicated in Fig.…”

Section: Resultsmentioning

confidence: 89%

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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