A Light Harvesting Policy on Black Counter Electrode for Enhanced Performance of Dye-Sensitized Solar Cells

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Chi-Hui Chien ◽  
Ming-Lang Tsai ◽  
Chi-Chang Hsieh ◽  
Yan-Huei Li ◽  
Yuh J. Chao

This work presents a novel light harvesting policy for a black counter electrode (BCE) to enhance the performance of dye-sensitized solar cells (DSSCs), which uses a metal-based light scattering layer (MLSL) that is formed from Al@SiO2 core-shell microflakes prepared and coated on BCE. DSSCs based on BCE with and without the MLSL are compared as well. Analysis results of electrochemical impedance spectra (EIS) indicate that, while not affecting the charge transfer resistance at BCE, MLSL exhibits a low electron transport resistance in the TiO2/electrolyte interface. Our results further demonstrate that MLSL reflects light to the TiO2 electrode, subsequently increasing photocurrent density by 68.68% (from 2.65 to 4.47 mA/cm2) and improving the power conversion efficiency by 49.64%.

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3053
Author(s):  
Mariia Becker ◽  
Catherine E. Housecroft ◽  
Edwin C. Constable

The effects of different I2 concentrations and different ionic liquids (ILs) in the electrolyte on the performances of dye-sensitized solar cells (DSCs) containing an iron(II) N-heterocyclic carbene dye and containing the I–/I3– redox shuttle have been investigated. Either no I2 was added to the electrolyte, or the initial I2 concentrations were 0.02, 0.05, 0.10, and 0.20 M. The short-circuit current density (JSC), open-circuit voltage (VOC), and the fill factor (ff) were influenced by changes in the I2 concentration for all the ILs. For 1-hexyl-3-methylimidazole iodide (HMII), low VOC and low ff values led to poor DSC performances. Electrochemical impedance spectroscopy (EIS) showed the causes to be increased electrolyte diffusion resistance and charge transfer resistance at the counter electrode. DSCs containing 1,3-dimethylimidazole iodide (DMII) and 1-ethyl-3-methylimidazole iodide (EMII) showed the highest JSC values when 0.10 M I2 was present initially. Short alkyl substituents (Me and Et) were more beneficial than longer chains. The lowest values of the transport resistance in the photoanode semiconductor were found for DMII, EMII, and 1-propyl-2,3-dimethylimidazole iodide (PDMII) when no I2 was added to the initial electrolyte, or when [I2] was less than 0.05 M. Higher [I2] led to decreases in the diffusion resistance in the electrolyte and the counter electrode resistance. The electron lifetime and diffusion length depended upon the [I2]. Overall, DMII was the most beneficial IL. A combination of DMII and 0.1 M I2 in the electrolyte produced the best performing DSCs with an average maximum photoconversion efficiency of 0.65% for a series of fully-masked cells.


2011 ◽  
Vol 347-353 ◽  
pp. 390-393 ◽  
Author(s):  
Shun Jian Xu ◽  
Yu Feng Luo ◽  
Wei Zhong ◽  
Guan Jun Qiao

A novel counter electrode has been fabricated at low temperature using nanoporous carbon (NC) with about 35 nm pore size as based catalysis materials and silver conductor paste (SCP) as connecting adhesive. The efficiency of dye-sensitized solar cells (DSCs) employing this SCP/NC electrode reaches to 5.91%, which is 15% higher than that of DSCs with NC electrode. The improved efficiency is attributed to the enhancement in the fill factor and the short circuit photocurrent density. Electrochemical impedance spectroscopy reveals that all of charge transfer resistance, ohmic serial resistance and Nernst diffusion impedance of SCP/NC electrode decrease compared with NC electrode. Especially, the efficiency of 5.91% is comparable to that of DSCs with Pt electrode.


2018 ◽  
Vol 5 (2) ◽  
pp. 171054 ◽  
Author(s):  
J. Llanos ◽  
I. Brito ◽  
D. Espinoza ◽  
Ramkumar Sekar ◽  
P. Manidurai

Y 1.86 Eu 0.14 WO 6 phosphors were prepared using a solid-state reaction method. Their optical properties were analysed, and they was mixed with TiO 2 , sintered, and used as a photoelectrode (PE) in dye-sensitized solar cells (DSSCs). The as-prepared photoelectrode was characterized by photoluminescence spectroscopy, diffuse reflectance, electrochemical impedance spectroscopy (EIS) and X-ray diffraction. The photoelectric conversion efficiency of the DSSC with TiO 2 :Y 1.86 Eu 0.14 WO 6 (100:2.5) was 25.8% higher than that of a DSCC using pure TiO 2 as PE. This high efficiency is due to the ability of the luminescent material to convert ultraviolet radiation from the sun to visible radiation, thus improving the solar light harvesting of the DSSC.


2012 ◽  
Vol 512-515 ◽  
pp. 242-245 ◽  
Author(s):  
Shun Jian Xu ◽  
Yu Feng Luo ◽  
Wei Zhong ◽  
Zong Hu Xiao ◽  
Xiao Yun Liu

Hexagonal boron nitride (HBN), which has the same crystal structure as graphite, has been used as catalytic material for a counter electrode in dye-sensitized solar cells (DSCs) to investigate its potential application. X-ray diffraction (XRD) has been used to confirm the crystal structure of HBN, scanning electron microscopy (SEM) has been used to characterize the morphology of HBN film on counter electrode, and electrochemical workstation has been employed to obtain the electrochemical impedance spectroscopy (EIS) and corresponding impedance parameters. Results show that the HBN film has rough surface and porous structure with pore size of less than 1 μm. When employed the HBN counter electrode to DSCs, the conversion efficiency (η) is only about a tenth of that of graphite based DSCs. Low efficiency of HBN based DSCs is induced by high charge transfer resistance (Rct) of HBN counter electrode, which means that HBN can hardly provide catalytic activity for the reduction of the triiodide ion. Therefore, the crystal structure is not a crucial factor to select the catalytic material for a counter electrode in DSCs. Moreover, the short circuit photocurrent density (Jsc) and the open circuit voltage (Voc) of device also evidently depend on the characteristics of catalytic material.


2011 ◽  
Vol 685 ◽  
pp. 1-5 ◽  
Author(s):  
Gui Qiang Wang ◽  
Wei Xing ◽  
Shu Ping Zhuo

Hierarchical porous carbons (HPC) were synthesized by a combination of self-assembly and chemical activation method. A mesoporous carbon with large-size pore was used as raw materials. N2sorption measurement indicated that plenty of micropores generated within the mesopore wall in the mesoporous carbon during KOH activation. Electrochemical impedance spectroscopy measurement demonstrated a high electrocatalytic activity of HPC electrode for triiodide reduction. The overall conversion efficiency of dye-sensitized solar cells with HPC counter electrode was 6.48%, which is similar to that of the device with conventional Pt counter electrode.


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