Bis(1,1-bis(2-pyridyl)ethane)copper(<scp>i</scp>/<scp>ii</scp>) as an efficient redox couple for liquid dye-sensitized solar cells

Cong, Jiayan; Kinschel, Dominik; Daniel, Quentin; Safdari, Majid; Gabrielsson, Erik; Chen, Hong; Svensson, Per H.; Sun, Licheng; Kloo, Lars

doi:10.1039/c6ta06782d

Cited by 66 publications

(81 citation statements)

References 18 publications

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“…32 This peak is not observed here since the PEDOT/electrolyte interface has a very small charge-transfer resistance less than 1 Ohm so that this peak is just superimposed to the higher resistive process (ii). 26,33 The data can be fitted by using the equivalent circuit shown in Figure S1. We note that the second Warburg impedance element is required to obtain a good fit for the low frequency peak, as we already discussed earlier.…”

Section: Resultsmentioning

confidence: 99%

Metal Complexes as Redox Shuttles in Dye-Sensitized Solar Cells Based on Electrodeposited ZnO: Tuning Recombination Kinetics and Conduction Band Energy

Rueß

Nguyen

Schlettwein

2018

J. Electrochem. Soc.

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In this work, a pathway to engineer both interfacial charge recombination kinetics and conduction band energy in dye-sensitized solar cells based on mesoporous electrodeposited ZnO is presented. Especially in solar cells employing metal complex redox shuttles such as Co(bpy) 3 [bpy = 2,2'-bipyridine] and Cu(tmby) 2 [tmby = 4,4',6,6'-tetramethyl-2,2'-bipyridine] these factors are crucial in order to obtain efficient devices. Controlling them is achieved by augmenting the liquid redox electrolyte with additives. The most commonly used additive 4-tert-butylpyridine (TBP) induces both an upward shift of the ZnO conduction band energy and retards recombination thus leading to higher device performance. However, the full potential of the cells cannot be exploited by TBP since high concentrations lead to unwanted side reactions. However, adding another additive such as 2,2'-bipyridine or neocuproine can circumvent these problems and opens a full range of options to tune the properties of the ZnO/electrolyte interface. Photoelectrochemical techniques, such as impedance spectroscopy, current-voltage characterization and photocurrent transient measurements are utilized to reveal the underlying mechanisms of the different additives. Using these additives, power-conversionefficiencies of 3.56% for a Co(bpy) 3 -based electrolyte and 3.85% for a Cu(tmby) 2 -based electrolyte are achieved for electrodeposited ZnO sensitized with the organic dye DN216. Dye-sensitized solar cells (DSSCs) are receiving continued interest as photovoltaic devices because they can be fabricated with low preparation expenses, 1,2 with solar-to-electrical power conversion efficiencies (PC Es) up to 14.3% under one sun illumination.3 Thereby they offer options with low energy payback times for a sustainable photovoltaic technology on a very large scale, or, at least for niche applications. In such cells, light is absorbed by dye molecules that are adsorbed to a mesoporous semiconductor. Following light absorption, the dye injects excited electrons into the conduction band of the semiconductor from where they are transported to the front contact. Then the oxidized dye molecules are regenerated by a redox mediator that, on the other hand, is regenerated by the counter electrode at the back contact. 4 Highest PC E is achieved by using nanoparticulate TiO 2 as semiconductor which has to undergo high-temperature treatments of about 400• C to ensure high electron collection efficiency. 5This treatment limits the applicability of DSSCs, since it increases the required energy input and also prevents the use of polymer foils as substrate material. In order to circumvent such high-temperature processes, ZnO has been applied as porous semiconductor because a well-connected network can be directly grown by electrodeposition from aqueous solutions at a typical process temperature of 70However, the PC E of ZnO-based DSSCs is inferior compared to TiO 2 -based cells. One of the reasons is the low quantum efficiency when ZnO is sensitized with dyes that were optimized ...

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Section: Resultsmentioning

confidence: 99%

Metal Complexes as Redox Shuttles in Dye-Sensitized Solar Cells Based on Electrodeposited ZnO: Tuning Recombination Kinetics and Conduction Band Energy

Rueß

Nguyen

Schlettwein

2018

J. Electrochem. Soc.

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“…Changes to the film thicknesses are noted in the manuscript where applicable. [16] Unless otherwise noted, the device electrolytes were as follows: B11 Electrolyte: 1.0 m DMII (1,3-dimethylimid azolium iodide), 0.05 m LiI, 30 × 10 −3 m I 2 , 0.5 m TBP (4-tertbutyl pyridine), 0.1 m GNCS (guanadinium thiocyanate) in acetonitrile (MeCN) and valeronitrile v/v (85/15); D35 or Y123 Electrolyte: 0.25 m Co(bpy) 3 (PF 6 ) 2 , 0.05 m Co(bpy) 3 (PF 6 ) 3 , 0.1 m LiTFSI, and 0.5 m TBP, in MeCN. Sensitization was performed at room temperature in the following solutions: 0.3 × 10 −3 m D35 in 4:1 EtOH:THF with 40× (12 × 10 −3 m) of chenodeoxycholic acid for 6 h; 0.2 × 10 −3 m Y123 in 1:1 MeCN:tert-butanol with 50 × CDCA for 6 h; and 0.3 × 10 −3 m B11 in 1:1:1 MeCN:tert-butanol:DMSO with 10 × CDCA for 20 h. [7a,8c] PFTS treatment: D35 sensitized TiO 2 films were submerged in a 0.1 m solution of 97% 1H,1H,2H,2H-perfluorooctyltrimethoxysilane in hexanes for 90 min at 30 °C.…”

Section: Methodsmentioning

confidence: 99%

The Role of Antireflective Coating CYTOP, Immersion Oil, and Sensitizer Selection in Fabricating a 2.3 V, 10% Power Conversion Efficiency SSM‐DSC Device

Cheema

Delcamp

2019

Advanced Energy Materials

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for maximizing power output from an illuminated area is through the use of multijunction solar cell constructs. [3] Recently, we put forward the first sequential series multijunction dye-sensitized solar cell (SSM-DSC), which could power solarto-fuel conversion directly from a single illuminated area. [4] This construct showed solar-to-fuel conversion efficiencies of up to 3% for CO 2 to CO and H 2 O to H 2 and O 2 reactions in the seminal report of a purely DSC-based technology powering these processes from a single illuminated area device without bias. [4b] The use of a DSC system to power these solar-to-fuel conversion processes is attractive due to the processability, stability, and already relatively high photovoltage outputs from DSC devices. [4a] The SSM-DSC construct capitalizes on the high photovoltages of traditional DSC devices in dividing photons according to potential energy to generate high voltage outputs through a summation of subcell photovoltages. SSM-DSC devices are simple to construct with a direct stacking of subcells sequentially wired in series. In this configuration, devices can be optimized individually in terms of TiO 2 thickness and sensitizer choice to achieve well-matched photocurrents for higher performing SSM-DSC devices since current is limited by the lowest current device in the series. However, within this design, significant light losses exist between each subcell, especially at the glass-air interface where diffraction and reflection are the highest due to significantly mismatched refractive indexes of glass (n = 1.52) and air (n = 1) (Figure 1). To minimize these losses, we put forward the use of a simple-to-apply antireflective coating in the form of CYTOP along with an immersion oil with a similar refractive index to glass between each subcell (Figure 2).CYTOP is known in the field of optoelectronics with recent uses as a gate dielectric, a support layer within devices, as a selfcleaning surface, a solution substrate patterning material, and as an insulating tunneling layer within devices. [5] No reports were apparent from our searches for the specific use of CYTOP as an antireflective coating with organic or dye-sensitized solar cells. The use of CYTOP and immersion oil as optical interfacial loss diminishing components allows for an increase of photon flux throughout the SSM-DSC system to boost photocurrent values for a more overall efficient system. Sequential series multijunction dye-sensitized solar cells (SSM-DSCs) canpower solar-to-fuel processes with a single illuminated area device. Dye selection and strategies limiting photon losses are critical in SSM-DSC devices for higher performance systems. Herein, an efficient and readily applicable spin coating protocol on glass surfaces with an antireflective fluoropolymer (CYTOP) is applied to an SSM-DSC architecture. Combining CYTOP with the use of an immersion oil between glass spacers in a three subcell SSM-DSC with judiciously selected TiO 2 photoanode sensitizers and thicknesses, an overall power conversion efficie...

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“…23 Very recently, Cong and coworkers reported a new copper-complex redox shuttle with bis(1,1-bis(2-pyridyl)ethane) copper(I/II), which yielded an overall efficiency of 9.0%. 24 However, the open-circuit voltage (V OC ) was not as high as that of the [Cu(dmp) 2 ] 2+/1+ device due to the relatively low redox potential. Herein, we introduced a copper-complex redox shuttle with [copper (6,6 0 Fig.…”

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confidence: 99%

Efficient dye-sensitized solar cells with [copper(6,6′-dimethyl-2,2′-bipyridine)₂]^2+/1+ redox shuttle

Yang

et al. 2017

RSC Adv.

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Bis(1,1-bis(2-pyridyl)ethane)copper(i/ii) as an efficient redox couple for liquid dye-sensitized solar cells

Abstract: A new redox couple, [Cu(bpye)2]+/2+, has been synthesized and applied in DSSCs. Overall efficiencies above 9.0% and good photostability were obtained. Excellent electrolyte charge transport, fast regeneration and low recombination are the major reasons for the high efficiencies.

Cited by 66 publications

References 18 publications

Metal Complexes as Redox Shuttles in Dye-Sensitized Solar Cells Based on Electrodeposited ZnO: Tuning Recombination Kinetics and Conduction Band Energy

Metal Complexes as Redox Shuttles in Dye-Sensitized Solar Cells Based on Electrodeposited ZnO: Tuning Recombination Kinetics and Conduction Band Energy

The Role of Antireflective Coating CYTOP, Immersion Oil, and Sensitizer Selection in Fabricating a 2.3 V, 10% Power Conversion Efficiency SSM‐DSC Device

Efficient dye-sensitized solar cells with [copper(6,6′-dimethyl-2,2′-bipyridine)₂]^2+/1+ redox shuttle

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Bis(1,1-bis(2-pyridyl)ethane)copper(i/ii) as an efficient redox couple for liquid dye-sensitized solar cells

Abstract: A new redox couple, [Cu(bpye)2]+/2+, has been synthesized and applied in DSSCs. Overall efficiencies above 9.0% and good photostability were obtained. Excellent electrolyte charge transport, fast regeneration and low recombination are the major reasons for the high efficiencies.

Cited by 66 publications

References 18 publications

Metal Complexes as Redox Shuttles in Dye-Sensitized Solar Cells Based on Electrodeposited ZnO: Tuning Recombination Kinetics and Conduction Band Energy

Metal Complexes as Redox Shuttles in Dye-Sensitized Solar Cells Based on Electrodeposited ZnO: Tuning Recombination Kinetics and Conduction Band Energy

The Role of Antireflective Coating CYTOP, Immersion Oil, and Sensitizer Selection in Fabricating a 2.3 V, 10% Power Conversion Efficiency SSM‐DSC Device

Efficient dye-sensitized solar cells with [copper(6,6′-dimethyl-2,2′-bipyridine)2]2+/1+ redox shuttle

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Efficient dye-sensitized solar cells with [copper(6,6′-dimethyl-2,2′-bipyridine)₂]^2+/1+ redox shuttle