scholarly journals Preparation of Nano-Ag-TiO2 Composites by Co-60 Gamma Irradiation to Enhance the Photocurrent of Dye-Sensitized Solar Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Le Thanh Nguyen Huynh ◽  
Viet Hai Le ◽  
Thanh Long Vo ◽  
Thi Kim Lan Nguyen ◽  
Quoc Hien Nguyen ◽  
...  
Keyword(s):  
Solar Cells ◽  
Charge Transfer ◽  
Electrochemical Impedance ◽  
Dye Sensitized Solar Cells ◽  
Energy Conversion Efficiency ◽  
Charge Transfer Resistance ◽  
Open Circuit ◽  
Transfer Resistance ◽  
Dye Sensitized ◽  
Sensitized Solar Cells

Nano-silver-titanium dioxide (Ag-TiO2) composites were prepared from commercial TiO2 (P25, Degussa) and silver nitrate (AgNO3) by gamma Co-60 irradiation method with various initial concentrations of AgNO3. The nano-AgTiO2 composites are utilized as the photoanode for dye-sensitized solar cells (DSCs). Under full sunlight illumination (1000 W/m2, AM 1.5), the efficiency of DSCs has improved significantly despite the Ag content of below 1%. The DSC—assembled with 0.75 Ag-TiO2 (0.75% Ag) photoanode—showed that the photocurrent was significantly enhanced from 8.1 mA.cm−2 to 9.5 mA.cm−2 compared to the DSCs using bared TiO2 photoanode. The unchanged open-circuit voltage resulted in the overall energy conversion efficiency to be increased by 25% from 3.75% to 4.86%. Electrochemical impedance spectroscopy (EIS) analysis showed that the charge transfer resistance is reduced when increasing Ag content, demonstrating that the charge transfer at TiO2/dye interface was enhanced in the presence of silver nanoparticles.

scholarly journals Electrochemical, Structural and Morphological Characterization of Hydrothermally Fabricated Binary Palladium Alloys PdCo and PdNi

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 796
Author(s):  
Edson Meyer ◽  
Raymond Taziwa ◽  
Dorcas Mutukwa ◽  
Nyengerai Zingwe
Keyword(s):  
Solar Cells ◽  
Charge Transfer ◽  
Binary Alloys ◽  
Dye Sensitized Solar Cells ◽  
Charge Transfer Resistance ◽  
Palladium Alloys ◽  
Transfer Resistance ◽  
Dye Sensitized ◽  
Sensitized Solar Cells

This article details the development and characterization of binary palladium alloys synthesized via a hydrothermal process. Palladium alloys, being good redox catalysts, could potentially replace platinum in many applications such as in dye sensitized solar cells, capacitors and vehicular catalytic converters where platinum is vital for maximum productivity. A good replacement should be cheap, readily available and be able to offer comparable catalytic activity to that of platinum. As such we hereby attempt to hydrothermally fabricate and characterize binary palladium alloys PdNi and PdCo that could be ideal replacements for platinum. XRD analysis of the as-synthesized binary alloys revealed the existence of only palladium peaks at 2θ values of 40.1°, 46.7°, 68.1°, 82.1° and 86.6°, indicative of the successful formation of the binary alloys. SEM micrographs revealed that both alloys consisted of spherical particles with PdCo agglomerating to an extent, whereas PdNi was widely distributed, thus it could enhance electrolyte adsorption during catalytic reduction reactions. Cyclic voltammetry analysis at 50 mV∙s−1 revealed that PdNi is more electrocatalytically active with a reduction current density of 41 mA∙cm−2 compared to 18 mA∙cm−2 for PdCo. Lower charge transfer resistance from electrochemical impedance spectroscopy confirmed the superior catalytic ability of PdNi. The two palladium alloys also produced maximum specific capacitances of 68 and 27 F∙g−1 for PdNi and PdCo respectively. Analysis of the sample stability yielded coulombic efficiency retention of 98.7 and 97% for PdNi and PdCo respectively after 1000 cycles. Results obtained have shown that the palladium alloys with their low charge transfer resistance could be ideal replacements for platinum in dye sensitized solar cells. Modest specific capacitance for PdNi illustrates its potential as an electrode catalyst in capacitors.

Study on the Change in Photovoltage by Control of Cell Gap in Dye-Sensitized Solar Cells

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Chaehyeon Lee ◽  
Weekyung Kang ◽  
Min Jae Ko ◽  
Kyoungkon Kim ◽  
Nam-Gyu Park
Keyword(s):  
Solar Cells ◽  
Electrochemical Impedance ◽  
Dye Sensitized Solar Cells ◽  
Energy Conversion Efficiency ◽  
Open Circuit ◽  
Electrolyte System ◽  
Counter Electrodes ◽  
Dye Sensitized ◽  
Transient Photovoltage ◽  
Sensitized Solar Cells

Photo-electrochemical properties of dye-sensitized solar cells (DSSCs) were investigated by changing the gap between working and counter electrodes. The open-circuit voltage (VOC) of DSSCs was significantly increased from 616 mV to 776 mV by about 26% with 1-methyl-3-butyl imidazolium iodide (BMII) based electrolyte and from 428 mV to 513 mV by 20% with lithium iodide (LiI) based electrolyte as the cell gap increased from 16 μm to 224 μm. From the electrochemical impedance spectroscopy, it was found that the resistance of the electrolyte was increased as the cell gap widened. This resulted in the reduction in the dark current associated with the VOC enhancement. The transient photovoltage spectroscopic measurement confirmed that the time constant for charge recombination between TiO2 and electrolyte became slower as the cell gap of the DSSC with LiI electrolyte increased, which could be an additional reason for the VOC enhancement. The optimal cell gap was determined to be around 31.3 μm for the BMII electrolyte system, and around 75.5 μm for the LiI electrolyte system in terms of the energy-conversion efficiency.

scholarly journals Dye-Sensitized Solar Cells Using Mesocarbon Microbead-Based Counter Electrodes

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Chien-Te Hsieh ◽  
Bing-Hao Yang ◽  
Wei-Yu Chen
Keyword(s):  
Solar Cells ◽  
Charge Transfer ◽  
Dye Sensitized Solar Cells ◽  
Charge Transfer Resistance ◽  
Counter Electrodes ◽  
Transfer Resistance ◽  
Dye Sensitized ◽  
Catalytic Sites ◽  
Low Charge ◽  
Sensitized Solar Cells

The dye-sensitized solar cells (DSCs) equipped with mesocarbon microbead (MCMB)-based counter electrodes were explored to examine their cell performance. Three types of nanosized additives including platinum, carbon nanotubes (CNTs), and carbon black (CB) are well dispersed and coated over microscaled MCMB powders. In the design of the counter electrodes, the MCMB graphite offers an excellent medium that allows charge transfer from the ITO substrate to the dye molecule. The active materials such as Pt, CNT, and nanosize CB act as an active site provider for the redox reaction. Among these counter electrodes, the DSCs fabricated with CB electrode exhibit the highest power conversion efficiency. This improved efficiency can be attributed to the fact that the CB nanoparticles not only offer a large number of catalytic sites but also low charge transfer resistance, facilitating a rapid reaction kinetics. Such design of carbon counter electrode has been confirmed to be a promising candidate for replacing Pt electrodes.

Copolymer-templated nitrogen-enriched nanocarbons as a low charge-transfer resistance and highly stable alternative to platinum cathodes in dye-sensitized solar cells

2015 ◽  
Vol 3 (8) ◽  
pp. 4413-4419 ◽  
Author(s):  
Myung Jong Ju ◽  
In Taek Choi ◽  
Mingjiang Zhong ◽  
Kimin Lim ◽  
Jaejung Ko ◽  
...  
Keyword(s):  
Solar Cells ◽  
Charge Transfer ◽  
Block Copolymers ◽  
High Performance ◽  
Dye Sensitized Solar Cells ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Dye Sensitized ◽  
Low Charge ◽  
Sensitized Solar Cells

High performance N-enriched nanocarbon CEs for organic DSSCs were synthesized by pyrolysis of self-assembled block copolymers.

An Efficient Metal Conductor Paste/Nanoporous Carbon Composite Counter Electrode for Dye-Sensitized Solar Cells

2011 ◽  
Vol 347-353 ◽  
pp. 390-393 ◽  
Author(s):  
Shun Jian Xu ◽  
Yu Feng Luo ◽  
Wei Zhong ◽  
Guan Jun Qiao
Keyword(s):  
Solar Cells ◽  
Counter Electrode ◽  
Electrochemical Impedance ◽  
Short Circuit ◽  
Dye Sensitized Solar Cells ◽  
Nanoporous Carbon ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Dye Sensitized ◽  
Sensitized Solar Cells

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.

scholarly journals There Is a Future for N-Heterocyclic Carbene Iron(II) Dyes in Dye-Sensitized Solar Cells: Improving Performance through Changes in the Electrolyte

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4181 ◽  
Author(s):  
Mariia Karpacheva ◽  
Vanessa Wyss ◽  
Catherine E. Housecroft ◽  
Edwin C. Constable
Keyword(s):  
Solar Cells ◽  
Alkyl Chain ◽  
Electrochemical Impedance ◽  
Short Circuit ◽  
Dye Sensitized Solar Cells ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Ion Concentration ◽  
Dye Sensitized ◽  
Sensitized Solar Cells

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.

scholarly journals Low-Cost and Efficient Nickel Nitroprusside/Graphene Nanohybrid Electrocatalysts as Counter Electrodes for Dye-Sensitized Solar Cells

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6563
Author(s):  
Md. Mahbubur Rahman
Keyword(s):  
Solar Cells ◽  
Low Cost ◽  
Photovoltaic Performance ◽  
Dye Sensitized Solar Cells ◽  
Solution Process ◽  
Charge Transfer Resistance ◽  
Counter Electrodes ◽  
Transfer Resistance ◽  
Dye Sensitized ◽  
Sensitized Solar Cells

Novel nickel nitroprusside (NNP) nanoparticles with incorporated graphene nanoplatelets (NNP/GnP) were used for the first time as a low-cost and effective counter electrode (CE) for dye-sensitized solar cells (DSSCs). NNP was synthesized at a low-temperature (25 °C) solution process with suitable purity and crystallinity with a size range from 5 to 10 nm, as confirmed by different spectroscopic and microscopic analyses. The incorporation of an optimized amount of GnP (0.2 wt%) into the NNP significantly improved the electrocatalytic behavior for the redox reaction of iodide (I-)/tri-iodide (I3-) by decreasing the charge-transfer resistance at the CE/electrolyte interface, lower than the NNP- and GnP-CEs, and comparable to the Pt-CE. The NNP/GnP nanohybrid CE when applied in DSSC exhibited a PCE of 6.13% (under one sun illumination conditions) with the Jsc, Voc, and FF of 14.22 mA/cm2, 0.628 V, and 68.68%, respectively, while the PCE of the reference Pt-CE-based DSSC was 6.37% (Jsc = 14.47 mA/cm2, Voc = 0.635 V, and FF = 69.20%). The low cost of the NNP/GnP hybrid CE with comparable photovoltaic performance to Pt-CE can be potentially exploited as a suitable replacement of Pt-CE in DSSCs.

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