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Effect of GeI2 and GeBr2 incorporation on perovskite properties and performance of carbon-based perovskite solar cells
(2023-04-01)
Aunping, Namfon
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Kumlangwan, Pantiwa
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Towannang, Madsakorn
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Chanlek, Narong
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Kumnorkaew, Pisist
CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> (MAPbI<inf>3</inf>) film was prepared by a convective method, and its X-ray diffraction spectrum displays the tetragonal perovskite structure. GeI<inf>2</inf> and GeBr<inf>2</inf> powders dissolve poorly in a mixed dimethylformamide-dimethylsulfoxide (DMF-DMSO) solvent, but the introduction of 5 wt% 5-ammonium valeric acid iodide (5-AVAI) into the mixed DMF-DMSO solvent greatly promotes GeI<inf>2</inf> and GeBr<inf>2</inf> solubility. XRD spectra of the (5-AVAI)MAPbI<inf>3</inf>, MAGe<inf>x</inf>Pb<inf>1–x</inf>I<inf>3</inf>, and MAGe<inf>x</inf>Pb<inf>1–x</inf>Br<inf>2x</inf>I<inf>3–2x</inf> (x = 0.0625 and 0.125) films exhibit a tetragonal perovskite structure, but the film morphologies become rougher than that of the pristine MAPbI<inf>3</inf> film. Discontinuous islands are formed on MAGe<inf>x</inf>Pb<inf>1–x</inf>I<inf>3</inf> and MAGe<inf>x</inf>Pb<inf>1–x</inf>Br<inf>2x</inf>I<inf>3–2x</inf> (x = 0.125) films. X-ray photoemission spectroscopy (XPS) analysis detected the Ge element on all Ge-doped films. The best performance levels of the carbon-based hole transport layer-free MAGe<inf>x</inf>Pb<inf>1–x</inf>I<inf>3–x</inf> (x = 0.0625, η= 3.63%) and MAGe<inf>x</inf>Pb<inf>1–x</inf>Br<inf>2x</inf>I<inf>3–2x</inf> (x = 0.0625, η = 2.95%) perovskite solar cells are lower than that of the pristine MAPbI<inf>3</inf>–based perovskite solar cell (η = 5.28%). This is likely due to the increased surface roughness, pin-holes, isolated islands, and the decreased light absorbance of the Ge-doped films in comparison with the pristine MAPbI<inf>3</inf> film.
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Influence of SCN− moiety on CH3NH3PbI3 perovskite film properties and the performance of carbon-based hole-transport-layer-free perovskite solar cells
(2022-01-01)
Prasan, Primprapha
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Aunping, Namfon
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Chanlek, Narong
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Kumlangwan, Pantiwa
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Towannang, Madsakorn
CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> perovskite films were prepared via a hot-casting method using six different CH<inf>3</inf>NH<inf>3</inf>I, PbI<inf>2</inf> and Pb(SCN)<inf>2</inf> solutions. Surface morphology of perovskite films with low SCN− dopant levels (0.0625 M and 0.125 M Pb(SCN)<inf>2</inf>) showed smooth surfaces and large grain sizes. However, with the high SCN− dopant levels (0.1875 M and 0.25 M Pb(SCN)<inf>2</inf>), rough surfaces were produced with pinholes. The crystal of pure CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> (0 M Pb(SCN)<inf>2</inf>) film is a tetragonal perovskite structure. XRD spectra of all five Pb(SCN)<inf>2</inf> added films show the present of CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> films and the additional peak at 12.66°. Rietveld refinement analysis reveals that the Pb(SCN)<inf>2</inf> addition causes the second phase PbI<inf>2</inf> formation along with the tetragonal MAPbI<inf>3</inf> perovskite film rather than the CH<inf>3</inf>NH<inf>3</inf>Pb(SCN)<inf>x</inf>I<inf>3-x</inf> perovskite formation. The carbon-based hole-transport-layer (HTL)-free perovskite (from 0.0625 M Pb(SCN)<inf>2</inf> dopant) solar cell is the optimal ratio in generating a promising cell efficiency, 6.34%, with a good efficiency retention of 79.43% after 30 days of testing in comparison to a pure CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> (0 M Pb(SCN)<inf>2</inf> dopant) perovskite solar cell with an efficiency retention of only 26.92%. The great stability of the Pb(SCN)<inf>2</inf> added perovskite solar cells is attributed to the PbI<inf>2</inf> layer covered MAPbI<inf>3</inf> grains blocking oxygen and/or water molecules from degrading MAPbI<inf>3</inf> perovskite.
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Effect of cell temperatures and flow-field patterns of bipolar plate electrodes on the performance of proton exchange membrane fuel cell by computational simulation
(2017-10-01)
Saraihom, Lirada
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Srimongkon, Kridsanapan
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Ruttanapun, Chesta
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Tangtrakarn, Apishok
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Faibut, Narit
The performances of fuel cell employing a bipolar plate with different gas-flow-field patterns for proton exchange membrane fuel cell (PEMFC) were simulated using higher-order polynomials (h-p) finite element method (h-p FEM). The patterns of each model were as follows: the straight pipe on both sides (Model 1), the serpentine flow-field for anode and the straight pipe for cathode (Model 2), the slotted serpentine for anode and the straight pipe for cathode (Model 3), and the serpentine on both sides (Model 4). It was found that as the cell temperature increased, the diffusion velocity of reactant gases and Maxwell-Stefan-diffusion coefficient of proton dramatically increased. The performance of PEMFC reached the highest value as the flow velocity of reactant gases and the diffusion coefficient of proton through membrane were optimized at the temperature of 80 °C. The most efficient flow-field pattern in this study is Model 2.
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A Flexible plastic-stainless steel dye-sensitized solar cell based on organic T-/T2 electrolyte
(2014-03-25)
Pimanpang, Samuk
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Towannang, Madsakorn
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Thiangkaew, Anongnad
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Maiaugree, Wasan
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Uppachai, Pikaned
SUMMARY: Flexible dye-sensitized solar cells (DSSCs) were fabricated using a TiO<inf>2</inf> film coated on stainless steel (TiO<inf>2</inf>/SS) as the working electrode and a Pt film coated on conductive plastic (Pt/plastic) as the counter electrode. Thin Pt film was deposited on conductive plastic specimens for four different deposition times (30, 60, 90 and 120s) using an electrochemical deposition process. Scanning electron micrographs of the resulting Pt films showed that Pt nanoparticles formed on conductive plastic. The DSSC characteristics were analyzed by illuminating light on the counter electrode. The performance of the cell with 30s of Pt deposition (30s-Pt) showed the highest DSSC efficiency, ~2.72%. Cell efficiency decreased with the duration of Pt deposition (or Pt thickness). This is attributed to the reduced transmittance through the thicker Pt films, which is supported by UV-visible spectroscopic measurements. © 2013 John Wiley & Sons, Ltd.
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Chemically deposited polypyrrole-nanoparticle counter electrode for inorganic I -/I 3 - and organic T -/T 2 dye-sensitized solar cells
(2012-12-01)
Towannang, Madsakorn
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Pimanpang, Samuk
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Thiangkaew, Anongnad
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Rutphonsan, Phikun
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Maiaugree, Wasan
Pure polypyrrole (PPy) and composited PPy-nanoparticles (multiwall carbon nanotubes (MWCNTs), nickel (Ni) or, titanium dioxide (TiO <inf>2</inf>)) films were coated on conductive glass by a chemical deposition method. They were used as dye-sensitized solar cell counter electrodes. The performance of pure PPy based dye-sensitized solar cells (DSSCs) was ∼6.00% and ∼2.81% for I -/I <inf>3</inf> - and T -/T <inf>2</inf> electrolytes, respectively. The efficiencies increased after MWCNTs and Ni nanoparticle incorporation for both electrolytes, but decreased with TiO <inf>2</inf> addition. PPy-MWCNTs DSSCs delivered the highest efficiency; ∼7.20% and ∼3.19% for I -/I <inf>3</inf> - and T -/T <inf>2</inf> electrolytes, respectively. The improvement of the energy conversion efficiency after MWCNTs and Ni incorporation is attributed to an increase in the electrode surface area and/or a reduction of charge-transfer resistance at the electrolyte/counter electrode interface. © 2012 Elsevier B.V.
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Co-electrophoretic deposition multiwall carbon nanotubes/Pt counter electrodes for dye-sensitized solar cell
(2012-10-01)
Maiaugree, Wasan
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Pimanpang, Samuk
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Towannang, Madsakorn
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Rutphonsan, Phikun
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Laupa, Seksan
Multiwall carbon nanotubes (MWCNTs) and platinum (Pt) were coated on fluorine doped tin oxide (FTO) coated glass by a direct current electrophoretic method, and were used as dye-sensitized solar cell counter electrodes. Scanning electron microscopy (SEM) detected the deposition of carbon nanotubes on FTO-glass. The deposition of Pt nanoparticles on carbon nanotube surfaces was confirmed by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Cell efficiencies of MWCNTs, Pt and MWCNTs/Pt dye-sensitized solar cells (DSSCs) were ∼1:41, ∼8:13, and ∼8:90%, respectively. The improvement of the composited MWCNTs/Pt cell efficiency is due to the presence of both catalysts (MWCNTs and Pt) enhancing counter electrode catalytic activity as observed by cyclic voltammetry (CV) and reducing charge-transfer resistance as observed by electrochemical impedance spectroscopy (EIS). © 2012 The Japan Society of Applied Physics.
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Optimization of TiO 2 nanoparticle mixed PEDOT-PSS counter electrodes for high efficiency dye sensitized solar cell
(2012-09-01)
Maiaugree, Wasan
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Pimanpang, Samuk
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Towannang, Madsakorn
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Saekow, Saman
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Jarernboon, Wirat
Poly(3,4-Ethylendioxythiophene)-Poly(Styrene Sulfonate) (PEDOT-PSS) mixed with titanium dioxide (TiO <inf>2</inf>) nanoparticles was coated on conductive glass substrate by a doctor blading method and used as dye-sensitized solar cell (DSSC) counter electrodes. The energy conversion efficiency is significantly improved after TiO <inf>2</inf> nanoparticle incorporation. This improvement is attributed to an increase in counter electrode catalytic activity and a decrease in counter electrode charge transfer resistance. These phenomena were observed using Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS), respectively. The efficiency of polymer-TiO <inf>2</inf> based DSSCs varied with the ratio of small (∼ 25 nm) to large (∼ 100 nm) TiO <inf>2</inf> nanoparticles. The highest efficiency (∼ 8.49%) was obtained with a ratio of 30% large to 70% small (wt/wt) nanoparticles inTiO <inf>2</inf> electrodes. This efficiency is superior to that of Pt DSSC (∼ 7.50%). © 2011 Elsevier B.V.
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High performance dye-sensitized solar cell based on hydrothermally deposited multiwall carbon nanotube counter electrode
(2012-06-11)
Siriroj, Sumeth
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Pimanpang, Samuk
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Towannang, Madsakorn
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Maiaugree, Wasan
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Phumying, Santi
Conductive glass was coated with multiwall carbon nanotubes (MWCNTs) by a hydrothermal method. MWCNTs films were subsequently used as dye-sensitized solar cell (DSSC) counter electrodes. The performance of hydrothermal MWCNT DSSC was ∼2.37%. After film annealing in an Ar atmosphere, annealed-hydrothermal MWCNT (AHT-CNT) DSSC efficiency was significantly increased to ∼7.66%, in comparison to ∼8.01% for sputtered-Pt DSSC. Improvement of AHT-CNT DSSC performance is attributed to a decrease in charge-transfer resistance from 1500Ω to 30Ω as observed by electrochemical impedance spectroscopy. © 2012 American Institute of Physics.

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