scholarly journals Electrolyte Concentration Effect of a Photoelectrochemical Cell Consisting of TiO2 Nanotube Anode

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Kai Ren ◽  
Yong X. Gan ◽  
Efstratios Nikolaidis ◽  
Sharaf Al Sofyani ◽  
Lihua Zhang
Keyword(s):  
Open Circuit Voltage ◽  
Electrolyte Concentration ◽  
Uv Light ◽  
Photocurrent Density ◽  
High Viscosity ◽  
Open Circuit ◽  
Photoelectrochemical Cell ◽  
Concentration Effect ◽  
Light Illumination ◽  
Applied Bias Voltage

The photoelectrochemical responses of a TiO2 nanotube anode in ethylene glycol (EG), glycerol, ammonia, ethanol, urea, and Na2S electrolytes with different concentrations were investigated. The TiO2 nanotube anode was highly efficient in photoelectrocatalysis in these solutions under UV light illumination. The photocurrent density is obviously affected by the concentration change. Na2S generated the highest photocurrent density at 0, 1, and 2 V bias voltages, but its concentration does not significantly affect the photocurrent density. Urea shows high open circuit voltage at proper concentration and low photocurrent at different concentrations. Externally applied bias voltage is also an important factor that changes the photoelectrochemical reaction process. In view of the open circuit voltage, EG, ammonia, and ethanol fuel cells show the trend that the open circuit voltage (OCV) increases with the increase of the concentration of the solutions. Glycerol has the highest OCV compared with others, and it deceases with the increase in the concentration because of the high viscosity. The OCV of the urea and Na2S solutions did not show obvious concentration effect.

Optical Adhesion Control of Hydrogel Microtools for On-Demand Immobilization and Measurement of Cells on a Microfluidic Chip

2010 ◽  
Vol 22 (5) ◽  
pp. 631-638 ◽  
Author(s):  
Hisataka Maruyama ◽  
◽  
Toshio Fukuda ◽  
Fumihito Arai ◽  
Keyword(s):  
Optical Tweezers ◽  
Microfluidic Chip ◽  
Electrolyte Concentration ◽  
Ph Value ◽  
Uv Light ◽  
Yeast Cells ◽  
Light Illumination ◽  
Local Conditions ◽  
On Demand ◽  
Adhesion Control

Optical adhesion control of hydrogel microtools, made of hydrophilic photo-crosslinkable resin, was developed for on-demand immobilization and measurement of cells on a microfluidic chip. The hydrogel microtool was manipulated by optical tweezers and modified by spiropyran chromospheres, which was a photochromic polymer. We developed on-demand control of uni/bidirectional adhesiveness of the microtool by control of electrolyte concentration in a solution. Photo illumination controls the adhesiveness of the microtools. In case of unidirectional control of adhesiveness, the microtools adhere to glass, other microtools and cells by illumination of ultraviolet (UV) light. Spiropyran chromospheres were used for bidirectional control of adhesiveness to cell. In case of bidirectional control of adhesiveness, the microtools adhere to cells by UV illumination. On the other hand, the microtool detaches from the adhered cells by visible (VIS) light illumination. Electrolyte concentration in the solution controlled these adhesiveness controls. Adherence of the microtool was enough to keep its position on a microfluidic chip. We applied these immobilization methods to measure the local conditions around cells by modifying the microtool with a pH indicator, bromothymol blue (BTB). Local measurements of the ambient pH value of yeast cells were performed by immobilizing the cell on the surface of the pH sensing microtool. Moreover, culture monitoring of a single yeast cell was demonstrated by immobilization to the microtool.

Crucial Role of the Electron Transport Layer and UV Light on the Open-Circuit Voltage Loss in Inverted Organic Solar Cells

2017 ◽  
Vol 9 (39) ◽  
pp. 34131-34138 ◽  
Author(s):  
Aurélien Tournebize ◽  
Giorgio Mattana ◽  
Thérèse Gorisse ◽  
Antoine Bousquet ◽  
Guillaume Wantz ◽  
...  
Keyword(s):  
Electron Transport ◽  
Organic Solar Cells ◽  
Crucial Role ◽  
Open Circuit Voltage ◽  
Uv Light ◽  
Open Circuit ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Voltage Loss

scholarly journals Development of a New Class of Thiocyanate-Free Cyclometalated Ruthenium(II) Complex for Sensitizing Nanocrystalline TiO2Solar Cells

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Surya Prakash Singh ◽  
Ashraful Islam ◽  
Masatoshi Yanagida ◽  
Liyuan Han
Keyword(s):  
Fill Factor ◽  
Open Circuit Voltage ◽  
Short Circuit ◽  
Power Conversion ◽  
Electrical Energy ◽  
Photocurrent Density ◽  
Open Circuit ◽  
Photoelectrochemical Cells ◽  
Broad Absorption ◽  
New Class

We designed and developed a new class of thiocyanate-free cyclometalated ruthenium sensitizers for sensitizing nanocrystalline TiO2solar cells. This complex shows appreciably broad absorption range. Anchoring to nanocrystalline TiO2films for light to electrical energy conversion in regenerative photoelectrochemical cells achieves efficient sensitization to TiO2electrode. With this new sensitizer, there were a power conversion efficiency of 4.76%, a short-circuit photocurrent density of 11.21 mA/cm2, an open-circuit voltage of 0.62 V, and a fill factor of 0.68 obtained under standard AM 1.5 sunlight.

Anticorrosion Behaviours of the TiO2 / WO3 Composite Photoelectrodes for 304 Stainless Steel

2007 ◽  
Vol 336-338 ◽  
pp. 2203-2206 ◽  
Author(s):  
Hong Yi Li ◽  
Yun Han Ling ◽  
Bo Jiang ◽  
Wu Feng Jiang ◽  
Zhi Hong Guo ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Uv Light ◽  
Composite Coatings ◽  
Dip Coating ◽  
Absorption Efficiency ◽  
High Reactivity ◽  
Open Circuit ◽  
304 Stainless Steel ◽  
Light Illumination ◽  
Coating Method

TiO2 is one kind of semiconductor-based photocatalyst. TiO2 shows relatively high reactivity and chemical stability under ultraviolet (UV) light. However TiO2 is a poor absorber of photons in visible light. In order to improve the absorption efficiency, the coatings of TiO2/WO3, WO3 and TiO2 on ITO were prepared by liquid phase deposition (LPD) and dip coating method, their microstructure, surface properties, photoelectrochemical properties are investigated in this paper. XRD results showed that the phases on the composite coatings are mainly anatase, rutile and WO3 respectively, the SEM results showed that the coatings of TiO2 and TiO2/WO3 are distributed evenly on the materials surface. The electrochemical experiment results showed that open circuit potential of TiO2 and TiO2/WO3 with presence of the UV light illumination were about -343 mV and –650 mV respectively, comparatively the rest potential of 304 stainless steel is about 48 mV, which means that the TiO2 or TiO2/WO3 coatings can protect 304 stainless steel from corrosion, and TiO2/WO3 coatings retained for a while anticorrosion even absence of UV light.

The Impact of Porphyrin Meso-Position Steric Effect on Porphyrin Density on TiO2 Surface of DSSC

2013 ◽  
Vol 683 ◽  
pp. 522-525 ◽  
Author(s):  
Zhe Zeng ◽  
Bao Zhang ◽  
Xiu Jun Liu ◽  
Xiao Peng ◽  
Shu Xian Meng ◽  
...  
Keyword(s):  
Fill Factor ◽  
Steric Effect ◽  
Open Circuit Voltage ◽  
Short Circuit ◽  
Photocurrent Density ◽  
Open Circuit ◽  
Cell Performance ◽  
Meso Position ◽  
The Impact ◽  
The Relationship

We have synthesized three novel porphyrin-based sensitizers, in which different substituents were introduced to meso- position. The relationship between meso- substituent and cell performance was investigated. We find porphyrin density could be a key point that affect cell device performance. The highest cell performance was obtained with 4-trans-vinyl- (2'-(5',10',15',20'-tetra (4''-isobutylphenyl) porphyrinato zinc(II))yl) benzoic acid, a short circuit photocurrent density of 10.25 mA cm-2 , an open –circuit voltage of 0.74 V, a fill factor of 68%, and a power conversion efficiency of 5.15% under standard AM 1.5 sunlight.

Properties of a-SiC:H films and solar cells

2000 ◽  
Vol 77 (9) ◽  
pp. 699-704
Author(s):  
R Gharbi ◽  
M Fathallah ◽  
C F Pirri ◽  
E Tresso ◽  
G Crovini ◽  
...  
Keyword(s):  
Solar Cells ◽  
Vapor Deposition ◽  
Open Circuit Voltage ◽  
Energy Gap ◽  
Chemical Vapor ◽  
Open Circuit ◽  
Light Illumination ◽  
High Hydrogen ◽  
Hydrogen Dilution ◽  
Effect Of Light

a-SiC:H samples and solar cells were made by plasma-enhanced chemical vapor deposition (PECVD) using a multichamber deposition system. The effect of light illumination on samples prepared with and without hydrogen dilution was studied. The phototransport properties of the samples prepared with high hydrogen dilution were more stable versus time of illumination than non diluted ones.The samples were inserted as an intrinsic layer in semitransparent solar cells. The performance of solar cells depends on the energy gap and thickness of the intrinsic layer. High hydrogen dilution may increase the energy gap and act to decrease the structure uniformity. The results show that open circuit voltage Voc decreases with light illumination and depends on the doped p+ layer quality and created defects in the intrinsic layer. PACS Nos.: 70, 72, 40

scholarly journals Catechol as a New Electron Hot Spot of Carbon Nitride

2020 ◽  
Author(s):  
Kimoon Lee ◽  
Jeonga Kim ◽  
Saehan Choi ◽  
Nyeongbeen Jo ◽  
yoonsung Nam
Keyword(s):  
Electron Transfer ◽  
Carbon Nitride ◽  
Hot Spot ◽  
Photocurrent Density ◽  
Light Sensitivity ◽  
Photochemical Activity ◽  
Open Circuit ◽  
Maximum Adsorption Capacity ◽  
Light Illumination ◽  
Post Modification

Graphitic carbon nitride (CNx) is a promising photocatalyst with visible-light sensitivity, attractive band-edge positions, tunable electronic structure, and eco-friendliness. However, their applications are limited by a low catalytic activity due to inefficient charge separation and insufficient visiblelight absorption. Here we show a new method to generate the electron polarization of CNx toward the edge via the chemical conjugation of catechol to CNx for enhanced photochemical activity. The electron-attracting property of catechol/quinone pairs induces the accumulation of photoexcited electrons at the edge of conjugated catechol-CNx hybrid nanostructure (Cat-CNx), , serving as an electron hot spot, as demonstrated by positive open-circuit photovoltage, which increases electron transfer through the conjugated catechol while suppressing charge recombination in the CNx. The catechol conjugation also widens the photoactive spectrum via the larger range delocalization of π-electrons. Accordingly, Cat-CNx reveals a 6.3 higher reductive photocurrent density than CNx. Gold ion reduction dramatically increased due to the enhanced electron transfer activity of Cat-CNx in cooperation with the inherent hydrophilicity and metal chelating property of catechols. Cat-CNx exhibits a 4.3 higher maximum adsorption capacity for gold ions under simulated sun light illumination compared to CNx. This work suggests that the post-modification of CNx’s π-conjugated system is a promising route to handle varied shortcomings and broaden availability of CNx.

scholarly journals Thermoelectric Microsensor Based on Ultrathin Si Films

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 1517
Author(s):  
Gustavo Gonçalves Dalkiranis ◽  
Pablo Ferrando-Villalba ◽  
Aitor Lopeandía-Fernández ◽  
Llibertat Abad-Muñoz ◽  
Javier Rodriguez-Viejo
Keyword(s):  
Seebeck Coefficient ◽  
Diode Laser ◽  
Atmospheric Pressure ◽  
Open Circuit Voltage ◽  
High Vacuum ◽  
Argon Laser ◽  
Open Circuit ◽  
Thermal Mass ◽  
Light Illumination ◽  
Si Films

We show the use as a thermal photosensor of a thermoelectric (TE) microsensor based on ultrathin suspended Si films. The reduced thickness of the structural films enhances the extremely large thermal insulation of the sensing area (~43 µW/K), since phonons scatter in the surfaces, and guarantees a reduced thermal mass (in the µJ/K range). The sensitivity of the device is evaluated by heating with an argon laser (λ = 457 nm) in the range 0–10 mW, reaching sensitivities of around 6 × 108 V/(W·m2) in high vacuum conditions and 5 × 107 V/(W·m2) in environments of air at atmospheric pressure. Open circuit voltage measurements with and without light illumination with a 406 nm diode laser operating at 4 mW were conducted at temperature differences up to 50 K between the central hot region and the Si frame. The slight decrease of the Seebeck coefficient is related to the increase of carriers by photogeneration.

scholarly journals PERFORMANCE of HYDROGENATED a-Si:H SOLAR CELLS with DOWNSHIFTING COATING

2011 ◽  
Vol 1321 ◽  
Author(s):  
Bill Nemeth ◽  
Yueqin Xu ◽  
Haorong Wang ◽  
Ted Sun ◽  
Benjamin G. Lee ◽  
...  
Keyword(s):  
Solar Cell ◽  
Open Circuit Voltage ◽  
Uv Light ◽  
Spectral Response ◽  
Red Light ◽  
Open Circuit ◽  
Narrow Line ◽  
Solar Cell Performance ◽  
Amorphous Si ◽  
Hydrogenated Amorphous

ABSTRACTWe apply a thin luminescent downshifting (LDS) coating to a hydrogenated amorphous Si (a-Si:H) solar cell and study the mechanism of possible current enhancement. The conversion material used in this study converts wavelengths below 400 nm to a narrow line around 615 nm. This material is coated on the front of the glass of the a-Si:H solar cell with a glass/TCO/p/i/n/Ag superstrate configuration. The initial efficiency of the solar cell without the LDS coating is above 9.0 % with open circuit voltage of 0.84 V. Typically, the spectral response below 400 nm of an a-Si:H solar cell is weaker than that at 615 nm. By converting ultraviolet (UV) light to red light, the solar cell will receive more red photons; therefore, solar cell performance is expected to improve. We observe evidence of downshifting in reflectance spectra. The cell Jsc decreases by 0.13 mA/cm2, and loss mechanisms are identified.

scholarly journals Alumina and Hafnia ALD Layers for a Niobium-Doped Titanium Oxide Photoanode

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Naji Al Dahoudi ◽  
Qifeng Zhang ◽  
Guozhong Cao
Keyword(s):  
Open Circuit Voltage ◽  
Dye Sensitized Solar Cells ◽  
Atomic Layer ◽  
Photocurrent Density ◽  
Open Circuit ◽  
Back Reaction ◽  
Photogenerated Electrons ◽  
Layer Deposition ◽  
Niobium Doped ◽  
Sensitized Solar Cells

Niobium-doped titanium dioxide (TiO2) nanoparticles were used as a photoanode in dye-sensitized solar cells (DSCs). They showed a high photocurrent density due to their higher conductivity; however, a low open-circuit voltage was exhibited due to the back-reaction of photogenerated electrons. Atomic layer deposition is a useful technique to form a conformal ultrathin layer of Al2O3and HfO, which act as an energy barrier to suppress the back electrons from reaching the redox medium. This resulted in an increase of the open-circuit voltage and therefore led to higher performance. HfO showed an improvement of the light-to-current conversion efficiency by 74%, higher than the 21% enhancement obtained by utilizing Al2O3layers.

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