Effects of TiO2 Blocking Layer on Photovoltaic Characteristics of TiO2/Nb2O5 Dye Sensitized Solar Cells

MRS Advances ◽  
2020 ◽  
Vol 5 (20) ◽  
pp. 1049-1058
Author(s):  
Brian O. Owino ◽  
Francis W. Nyongesa ◽  
Alex A. Ogacho ◽  
Bernard O. Aduda ◽  
Benjamin V. Odari

ABSTRACTThis study reports on the effect of introducing TiO2 compact layer on the photovoltaic characteristics of TiO2/Nb2O5 composite dye sensitized solar cell. The compact layer was deposited by spray pyrolysis technique. It was observed that introduction of 60 nm thick compact layer improved the short circuit current density Jsc ,Open circuit voltage Voc, and efficiency of the cell from 4.9 mA/cm2 to 8.2 mA/cm2, 6.8×10-1 V to 7.2×10-1 V and 1.9 % to 3.4 % respectively compared to traditional cell prepared without compact layer. Electrochemical impedance spectroscopy confirmed an increase in recombination resistance from 5.5×101 Ω.cm2 for bare DSSC to 9.0×101 Ω.cm2 for DSSC with compact layer thereby improving electron lifetime of the cells from 2.5×10-4 s to 386.9×10-4 s.

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.


2017 ◽  
Vol 80 (1) ◽  
Author(s):  
Zainal Arifin ◽  
Sudjito Soeparman ◽  
Denny Widhiyanuriyawan ◽  
Suyitno Suyitno ◽  
Argatya Tara Setyaji

Natural dyes have attracted much researcher’s attention due to their low-cost production, simple synthesis processes and high natural abundance. However the dye-sensitized solar cells (DSSCs) based natural dyes have higher tendency to degradation. This article reports on the enhancement of performance and stability of dye-sensitized solar cells (DSSCs) using natural dyes. The natural dyes were extracted from papaya leaves by ethanol solvent at a temperature of 50 °C. Then the extracted dyes were isolated and modified into Mg-chlorophyll using column chromatography. Mg-chlorophyll was then synthesized into Fe-chlorophyll to improve stability. The natural dyes were characterized using ultraviolet-visible spectrometry, Fourier transform infrared spectroscopy, and cyclic voltammetry. The performance of DSSCs was tested using a solar simulator. The results showed the open-circuit voltage, the short-circuit current density, and the efficiency of the extracted papaya leaves-based DSSCs to be 325 mV, 0.36 mA/cm2, and 0.07%, respectively. Furthermore, the DSSCs with purified chlorophyll provide high open-circuit voltage of 425 mV and short-circuit current density of 0.45 mA/cm2. The use of Fe-chlorophyll for sensitizing the DSSCs increases the efficiency up to 2.5 times and the stability up to two times. The DSSCs with Fe-chlorophyll dyes provide open-circuit voltage, short-circuit current density, and efficiency of 500 mV, 0.62 mA/cm2, and 0.16%, respectively. Further studies to improve the current density and stability of natural dye-based DSSCs along with an improvement in the anchor between dyes and semiconducting layers are required.


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.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Parth Bhatt ◽  
Kavita Pandey ◽  
Pankaj Yadav ◽  
Brijesh Tripathi ◽  
Manoj Kumar

This paper investigates the effect of ageing on the performance of dye-sensitized solar cells (DSCs). The electrical characterization of fresh and degraded DSCs is done under AM1.5G spectrum and the current density-voltage (J-V) characteristics are analyzed. Short circuit current density (JSC) decreases significantly whereas a noticeable increase in open circuit voltage is observed. These results have been further investigated electroanalytically using electrochemical impedance spectroscopy (EIS). An increase in net resistance results in a lower JSC for the degraded DSC. This decrease in current is mainly due to degradation of TiO2-dye interface, which is observed from light and dark J-V characteristics and is further confirmed by EIS measurements. A reduction in the chemical capacitance of the degraded DSC is observed, which is responsible for the shifting of Fermi level with respect to conduction band edge that further results in an increase of open circuit voltage for the degraded DSC. It is also confirmed from EIS that the degradation leads to a better contact formation between the electrolyte and Pt electrode, which improves the fill factor of the DSC. But the recombination throughout the DSC is found to increase along with degradation. This study suggests that the DSC should be used under low illumination conditions and around room temperature for a longer life.


2011 ◽  
Vol 64 (7) ◽  
pp. 951 ◽  
Author(s):  
Perumal Rajakumar ◽  
Kathiresan Visalakshi ◽  
Shanmugam Ganesan ◽  
Pichai Maruthamuthu ◽  
Samuel Austin Suthanthiraraj

Synthesis of polyolefinic aromatic molecules with pyrene as the surface group, and their role as an additive in the redox couple of dye-sensitized solar cells, is described. The studies yield a promising power conversion efficiency of 5.27% with a short circuit current density of 6.50 mA cm–2, an open circuit voltage of 0.60 V, and a fill factor of 0.54 under 40 mW cm–2 simulated air mass (A.M.) 1.5 illumination. Most importantly, the photocurrent responsivity increases with an increase in the number of pyrene units on the surface.


2011 ◽  
Vol 378-379 ◽  
pp. 636-641
Author(s):  
Cheng Chiang Chen ◽  
Lung Chien Chen ◽  
Shu Jung Kuo

This study examined the nanostructure InN compact layer and Au nano particles to dye-sensitized solar cells (DSSCs).We presents the DSSCs with Nitrided indium compact layer (InN-CPL) prepared by radiofrequency magnetron sputtering and doping Au particle in photoelectrode. The InN-CPL effectively reduces the back reaction in the interface between the indium tin oxide (ITO) transparent conductive film and the electrolyte in the DSSC. The Au particles effect conduction band of the TiO2 to rise open-circuit voltage to 0.7 v. The Au particles effectively rise inject electrons efficiency. For the DSSC without InN-CPL, the short-circuit current density and solar energy conversion efficiency are 15.6 mA/cm2 and 6.35 %, respectively. However, DSSCs with InN-CPL effectively rise short-circuit current density. The DSSC fabricated on 90 nm InN-CPL and doping Au particle showed the maximum power conversion efficiency of 8.9 % (AM1.5G) due to effective prevention of the electron transfer to electrolyte.


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Seigo Ito ◽  
Kaoru Takahashi

To improve the durability of dye-sensitized solar cells (DSCs), monolithic DSCs with ionic liquid electrolyte were studied. Deposited by screen printing, a carbon layer was successfully fabricated that did not crack or peel when annealing was employed beforehand. Optimized electrodes exhibited photovoltaic characteristics of 0.608 V open-circuit voltage, 6.90 cm−2 mA short-circuit current, and 0.491 fill factor, yielding 2.06% power conversion efficiency. The monolithic DSC using ionic liquid electrolyte was thermally durable and operated stably for 1000 h at 80°C.


Author(s):  
Edwin Peng ◽  
Halil Berberoglu

This paper reports the temperature and irradiance dependence of dye-sensitized solar cells (DSSCs) with acetonitrile-based electrolytes. The prototyped DSSCs had nanocrystalline titanium dioxide photoanodes and platinum thin film cathode. The photoanodes were sensitized with N-749 dye. The current-voltage characteristics of the DSSCs were measured at temperatures from 5 to 50 °C and under 500, 1000, and 1500 W m−2 irradiance. The open circuit voltage, VOC, decreased linearly with increasing temperature and had positive, logarithmic relation with irradiance. At temperatures lower than 15 °C, short circuit current density, JSC, was limited by the diffusion of I3− in the electrolyte and increased with increasing temperature. At higher temperatures the recombination of electrons injected into the TiO2 conduction band was dominant over diffusion and JSC decreased with increasing temperature. Moreover, JSC increaed linearly with increasing irradiance. The DSSC photoconversion efficiency did not vary appreciably at temperatures lower than 15 °C but decreased with increasing temperature. Finally, the efficiency increased with increasing irradiance.


2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
Ru-Yuan Yang ◽  
Huang-Yu Chen ◽  
Fu-Der Lai

We investigated the change of the electric characteristics in dye-sensitized solar cell (DSSC) when the electrolyte has been injected and measured initially and lately for a period of time. It was found that the short-circuit current density decreased from 9.799 mA/cm2to 7.056 mA/cm2and the fill factor increased from 0.406 to 0.559 when the cell had stood for an hour, while the open-circuit photovoltage did not change due to fixed difference between the Fermi level of TiO2and the oxidation-reduction potential of electrolyte. The results can be explained by using the variation of the series resistance in the equivalent circuit of the DSSC.


2014 ◽  
Vol 602-603 ◽  
pp. 888-892
Author(s):  
Yan Xiang Wang ◽  
Yu Hong Ye ◽  
Jian Sun

Titanium dioxide (TiO2) nanotubes film was deposited on conducting glass oxide (FTO) by using ZnO nanorods as template, and the TiO2nanotubes film was applied in DSCs. First, ZnO nanorods were fabricated on ZnO-doped TiO2seed layer coated substrates by the hydrothermal method. Second, the obtained ZnO nanorods were used as a template to synthesize ZnOTiO2coreshell structure through the immersion method. Third, the ZnO nanorods template was removed by etching method to obtained TiO2nanotubes film. The thickness of ZnO-doped TiO2seed layer is about 200nm and the crystalline size of nanoparticles are about 5~10nm. The length of the ZnO nanorods are about 1~3μm. The TiO2nanotube was composed of TiO2nanoparticles. The short-circuit current density (Jsc), open-circuit voltage, fill factor (FF) and efficiency of TiO2nanotubes DSC were 4.63 mA·cm-2, 0.74V, 62% and 2.15%, respectively.


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