Edge-carboxylated graphene nanoplatelets as oxygen-rich metal-free cathodes for organic dye-sensitized solar cells

2014 ◽  
Vol 7 (3) ◽  
pp. 1044-1052 ◽  
Author(s):  
Myung Jong Ju ◽  
In-Yup Jeon ◽  
Kimin Lim ◽  
Jae Cheon Kim ◽  
Hyun-Jung Choi ◽  
...  

Edge-carboxylated graphene nanoplatelets (ECGnPs) prepared by the dry ball-milling of graphite showed lower charge-transfer resistance (RCT) and better electrochemical stability for the JK-303-based solar cell with Co(bpy)32+/3+ redox couple.

2016 ◽  
Vol 4 (23) ◽  
pp. 9029-9037 ◽  
Author(s):  
Hong Mo Kim ◽  
In-Yup Jeon ◽  
In Taek Choi ◽  
Sung Ho Kang ◽  
Sun-Hee Shin ◽  
...  

Edge-selectively antimony-doped graphene nanoplatelet electrocatalysts exhibited an extremely low charge transfer resistance with “zero-loss stability” for a cobalt redox couple.


Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 796
Author(s):  
Edson Meyer ◽  
Raymond Taziwa ◽  
Dorcas Mutukwa ◽  
Nyengerai Zingwe

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.


RSC Advances ◽  
2016 ◽  
Vol 6 (2) ◽  
pp. 1637-1643 ◽  
Author(s):  
Min Zheng ◽  
Jinghao Huo ◽  
Yongguang Tu ◽  
Jinbiao Jia ◽  
Jihuai Wu ◽  
...  

PEDOT/Fe3O4 hybrid is in situ polymerized and used as Pt-free counter electrode in dye-sensitized solar cell. Owing to large active area and low charge transfer resistance for the hybrid, the cell achieves a high power conversion efficiency of 8.69%.


ACS Nano ◽  
2013 ◽  
Vol 7 (6) ◽  
pp. 5243-5250 ◽  
Author(s):  
Myung Jong Ju ◽  
Jae Cheon Kim ◽  
Hyun-Jung Choi ◽  
In Taek Choi ◽  
Sang Gyun Kim ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6563
Author(s):  
Md. Mahbubur Rahman

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.


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 ◽  
...  

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.


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Chien-Te Hsieh ◽  
Bing-Hao Yang ◽  
Wei-Yu Chen

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.


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