scholarly journals Are Alkynyl Spacers in Ancillary Ligands in Heteroleptic Bis(diimine)copper(I) Dyes Beneficial for Dye Performance in Dye-Sensitized Solar Cells?

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1528 ◽  
Author(s):  
Guglielmo Risi ◽  
Mariia Becker ◽  
Catherine E. Housecroft ◽  
Edwin C. Constable

The syntheses of 4,4′-bis(4-dimethylaminophenyl)-6,6′-dimethyl-2,2′-bipyridine (1), 4,4′-bis(4-dimethylaminophenylethynyl)-6,6′-dimethyl-2,2′-bipyridine (2), 4,4′-bis(4-diphenylaminophenyl)-6,6′-dimethyl-2,2′-bipyridine (3), and 4,4′-bis(4-diphenylaminophenylethynyl)-6,6′-dimethyl-2,2′-bipyridine (4) are reported along with the preparations and characterisations of their homoleptic copper(I) complexes [CuL2][PF6] (L = 1–4). The solution absorption spectra of the complexes exhibit ligand-centred absorptions in addition to absorptions in the visible region assigned to a combination of intra-ligand and metal-to-ligand charge-transfer. Heteroleptic [Cu(5)(Lancillary)]+ dyes in which 5 is the anchoring ligand ((6,6′-dimethyl-[2,2′-bipyridine]-4,4′-diyl)bis(4,1-phenylene))bis(phosphonic acid) and Lancillary = 1–4 have been assembled on fluorine-doped tin oxide (FTO)-TiO2 electrodes in dye-sensitized solar cells (DSCs). Performance parameters and external quantum efficiency (EQE) spectra of the DSCs (four fully-masked cells for each dye) reveal that the best performing dyes are [Cu(5)(1)]+ and [Cu(5)(3)]+. The alkynyl spacers are not beneficial, leading to a decrease in the short-circuit current density (JSC), confirmed by lower values of EQEmax. Addition of a co-absorbent (n-decylphosphonic acid) to [Cu(5)(1)]+ lead to no significant enhancement of performance for DSCs sensitized with [Cu(5)(1)]+. Electrochemical impedance spectroscopy (EIS) has been used to investigate the interfaces in DSCs; the analysis shows that more favourable electron injection into TiO2 is observed for sensitizers without the alkynyl spacer and confirms higher JSC values for [Cu(5)(1)]+.

2018 ◽  
Vol 9 ◽  
pp. 3069-3078 ◽  
Author(s):  
Mariia Karpacheva ◽  
Catherine E Housecroft ◽  
Edwin C Constable

We demonstrate that the performances of dye-sensitized solar cells (DSCs) sensitized with a previously reported N-heterocyclic carbene iron(II) dye in the presence of chenodeoxycholic acid co-adsorbant, can be considerably improved by altering the composition of the electrolyte while retaining an I−/I3 − redox shuttle. Critical factors are the solvent, presence of ionic liquid, and the use of the additives 1-methylbenzimidazole (MBI) and 4-tert-butylpyridine (TBP). For the electrolyte solvent, 3-methoxypropionitrile (MPN) is preferable to acetonitrile, leading to a higher short-circuit current density (J SC) with little change in the open-circuit voltage (V OC). For electrolytes containing MPN, an ionic liquid and MBI (0.5 M), DSC performance depended on the ionic liquid with 1-ethyl-3-methylimidazolium hexafluoridophosphate (EMIMPF) > 1,2-dimethyl-3-propylimidazolium iodide (DMPII) > 1-butyl-3-methylimidazolium iodide (BMII) ≈ 1-butyl-3-methylimidazolium hexafluoridophosphate (BMIMPF). Omitting the MBI leads to a significant improvement in J SC when the ionic liquid is DMPII, BMII or BMIMPF, but with EMIMPF the removal of the MBI additive results in a dramatic decrease in V OC (542 to 42 mV). For electrolytes containing MPN and DMPII, the effects of altering the MBI concentration have also been investigated. Although the addition of TBP improves V OC, it causes significant decreases in J SC. The best performing DSCs with the NHC-iron(II) dye employ an I−/I3 −-based electrolyte with MPN as solvent, DMPII ionic liquid (0.6 M) with no or 0.01 M MBI; values of J SC = 2.31 to 2.78 mA cm−2, V OC = 292 to 374 mV have been achieved giving η in the range of 0.47 to 0.57% which represents 7.8 to 9.3% relative to an N719 reference DSC set at 100%. Electrochemical impedance spectroscopy has been used to understand the role of the MBI additive in the electrolytes.


Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4181 ◽  
Author(s):  
Mariia Karpacheva ◽  
Vanessa Wyss ◽  
Catherine E. Housecroft ◽  
Edwin C. Constable

By systematic tuning of the components of the electrolyte, the performances of dye-sensitized solar cells (DSCs) with an N-heterocyclic carbene iron(II) dye have been significantly improved. The beneficial effects of an increased Li+ ion concentration in the electrolyte lead to photoconversion efficiencies (PCEs) up to 0.66% for fully masked cells (representing 11.8% relative to 100% set for N719) and an external quantum efficiency maximum (EQEmax) up to approximately 25% due to an increased short-circuit current density (JSC). A study of the effects of varying the length of the alkyl chain in 1-alkyl-3-methylimidazolium iodide ionic liquids (ILs) shows that a longer chain results in an increase in JSC with an overall efficiency up to 0.61% (10.9% relative to N719 set at 100%) on going from n-methyl to n-butyl chain, although an n-hexyl chain leads to no further gain in PCE. The results of electrochemical impedance spectroscopy (EIS) support the trends in JSC and open-circuit voltage (VOC) parameters. A change in the counterion from I− to [BF4]− for 1-propyl-3-methylimidazolium iodide ionic liquid leads to DSCs with a remarkably high JSC value for an N-heterocyclic carbene iron(II) dye of 4.90 mA cm−2, but a low VOC of 244 mV. Our investigations have shown that an increased concentration of Li+ in combination with an optimized alkyl chain length in the 1-alkyl-3-methylimidazolium iodide IL in the electrolyte leads to iron(II)-sensitized DSC performances comparable with those of containing some copper(I)-based dyes.


2010 ◽  
Vol 93-94 ◽  
pp. 31-34 ◽  
Author(s):  
A. Chindaduang ◽  
Pattasuda Duangkaew ◽  
Sirapat Pratontep ◽  
Gamolwan Tumcharern

We focus on the energy conversion improvement of dye-sensitized solar cells by using poly(ethylene oxide)-multi-walled carbon nanotube (PEO-MWCNT) electrolyte. Compared with the MWCNT-free solar cells, the addition of 0.05 wt.% MWCNTs in the polymer electrolyte results in a dramatic increase of the short-circuit current (Jsc), consequently raising the device performance by approximately 9% under a direct light of the Air Mass 1.5 irradiation at 100 mW cm-2. The role of the conductive carbon materials in the polymer electrolyte have been investigated by means of ionic conductometry, electrochemical impedance spectroscopy and UV-visible spectroscopy. This work demonstrates that MWCNT additives in polymer electrolytes is a convenient yet effective strategy for improving the performance of photovoltaic devices.


2007 ◽  
Vol 31 ◽  
pp. 176-178
Author(s):  
Hyeon Seok Lee ◽  
Heon Yong Lee ◽  
S.Y. Ahn ◽  
K.H. Kim ◽  
J.Y. Kwon

We fabricated improved carbon counter electrodes to improve conversion efficiency of dye sensitized solar cells (DSSCs). Unlike conventional carbon counter electrodes, we added small quantity of TiO2 nano powder and used chemical sintering methodology developed by Park’s group to make surface morphology of the electrodes to change. Through these methods, we could observe change of surface morphology of carbon electrodes and influences on short circuit current density (JSC) and conversion efficiency.


2018 ◽  
Vol 6 (45) ◽  
pp. 22508-22512 ◽  
Author(s):  
Naohiko Kato ◽  
Shinya Moribe ◽  
Masahito Shiozawa ◽  
Ryo Suzuki ◽  
Kazuo Higuchi ◽  
...  

To realize highly efficient solid-state dye-sensitized solar cells (SDSCs), the absorption range of the dye should be extended to the near-IR range to increase short-circuit current density (Jsc); a high Jsc in turn requires a highly conductive p-type semiconductor.


2021 ◽  
Vol 15 (1) ◽  
pp. 58
Author(s):  
Najihah M.Z. ◽  
Winie Tan

Current work employs dye extracted from leaves of Costus woodsonii as a new sensitizer for dye-sensitized solar cells (DSSCs). The leave was extracted in three different solvents namely ethanol, methanol, and acetone. Extraction of leaves was carried out by the freezing method. DSSCs with the configuration of TiO2/dye/electrolyte/Pt were assembled. The dyes in DSSCs were Costus woodsonii leaves extracted in methanol, ethanol, and acetone. DSSC with methanol extract of leaves has an efficiency of 0.23 % and short-circuit current density (Jsc) of 0.63 mA cm-2.  DSSC sensitized with ethanol extract of leaves has an efficiency of 0.37 % and Jsc of 0.85 mA cm-2. DSSC sensitized with acetone extract of leaves shows the highest efficiency of 0.48 % and Jsc of 1.35 mA cm-2. The performance of the DSSCs in this work is compared with other natural dye-based DSSCs. The efficiency obtained in this work is better or at par with the works reported by other researchers. Keywords: Natural dye; Costus woodsonii; Leave; Dye-sensitized solar cells


RSC Advances ◽  
2014 ◽  
Vol 4 (80) ◽  
pp. 42252-42259 ◽  
Author(s):  
Shengbo Zhu ◽  
Zhongwei An ◽  
Xinbing Chen ◽  
Pei Chen ◽  
Qianfeng Liu

The modification of the π-linker of cyclic thiourea functionalized dyes has a significant effect on the short-circuit current density and open-circuit voltage of dye-sensitized solar cells.


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
D. M. B. P. Ariyasinghe ◽  
H. M. N. Bandara ◽  
R. M. G. Rajapakse ◽  
K. Murakami ◽  
M. Shimomura

The surface modification of a TiO2electrode with diethyldithiocarbamate (DEDTC) in dye-sensitized solar cells (DSSCs) was studied. Results from X-ray photoelectron spectroscopy (XPS) indicate that over half of the sulfur atoms become positively charged after the DEDTC treatment of the TiO2surface. DSSCs were fabricated with TiO2electrodes modified by adsorbing DEDTC using a simple dip-coating process. The conversion efficiency of the DSSCs has been optimized to 6.6% through the enhancement of the short-circuit current density ( mA/cm2). This is substantially higher compared to the efficiency of 5.9% ( mA/cm2) for the DSSCs made with untreated TiO2electrodes.


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