Photoelectrochemical hydrogen generation employing a Cu2O-based photocathode with improved stability and activity by using NixPy as the cocatalyst

2018 ◽  
Vol 20 (22) ◽  
pp. 15300-15306 ◽  
Author(s):  
Manjeet Chhetri ◽  
C. N. R. Rao
Keyword(s):  
Hydrogen Generation ◽  
Charge Recombination ◽  
Band Edge ◽  
Improved Stability ◽  
Reduce Charge Recombination

With the tactical integration of band edge energetics concepts in semiconducting films to reduce charge recombination and photocorrosion, an improvement in the photocurrent can be achieved by introducing CuO and NixPy into Cu2O films.

scholarly journals How to Reduce Charge Recombination in Organic Solar Cells: There are Still Lessons to Learn from P3HT:PCBM

2021 ◽  
pp. 2001056
Author(s):  
Sebastian Wilken ◽  
Dorothea Scheunemann ◽  
Staffan Dahlström ◽  
Mathias Nyman ◽  
Jürgen Parisi ◽  
...  
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
Charge Recombination ◽  
Reduce Charge Recombination

SURFACE-CHARGE-ENABLED PHOTOLYTIC HYDROGEN GENERATION IN V2O5·H2O/Au NANOCONJUGATES

MRS Advances ◽  
2016 ◽  
Vol 1 (46) ◽  
pp. 3121-3126
Author(s):  
Sunith Varghese ◽  
Charuksha Walgama ◽  
Mark Wilkins ◽  
Sadagopan Krishnan ◽  
Kaan Kalkan
Keyword(s):  
Surface Charge ◽  
Hydrogen Generation ◽  
Hydrogen Reduction ◽  
Energy Levels ◽  
Sol Gel ◽  
Band Edge ◽  
Conduction Band Edge ◽  
Current Voltage ◽  
Negative Surface ◽  
Negative Surface Charge

ABSTRACTThe present work investigates sol-gel synthesized vanadium oxyhydrate (V2O5·H2O) nanowires decorated with Au nanoparticles as potential photolytic H2 generators. As determined by UV photoelectron and optical spectroscopies, the conduction band edge of V2O5·H2O lies 0.6 eV below standard H+ reduction potential, implying no H2 can be generated. On the contrary, as measured by gas chromatography, our nanoconjugates yield reproducible light-to-hydrogen conversion efficiency of 5.3%, for the first hour of photolysis under 470 nm excitation. To explain the observed hydrogen reduction, we have hypothesized the vanadia electron energy levels are raised by some negative surface charge. With the objective of validating this hypothesis, we have performed cyclic current-voltage measurements. The derived conduction and valence band edge energies are not only consistent with the optical band gaps, but also validate the hypothesized energy increase by 1.6 eV, respectively. The negative surface charge is also corroborated by the ζ-potential. Based on the measured pH of 2.4, we attribute the negative surface charge to Lewis acid nature of the nanowires, establishing dative bonding with OH−. The present work establishes the importance of surface charge in photoelectrochemical reactions, where it can be instrumental and enabling in photolytic fuel production.

Charge Recombination and Band-Edge Shift in the Dye-Sensitized Mg2+-Doped TiO2Solar Cells

2011 ◽  
Vol 115 (33) ◽  
pp. 16418-16424 ◽  
Author(s):  
Changneng Zhang ◽  
Shuanghong Chen ◽  
Li’e Mo ◽  
Yang Huang ◽  
Huajun Tian ◽  
...  
Keyword(s):  
Charge Recombination ◽  
Band Edge ◽  
Dye Sensitized

Fluorine Substituents Reduce Charge Recombination and Drive Structure and Morphology Development in Polymer Solar Cells

2013 ◽  
Vol 135 (5) ◽  
pp. 1806-1815 ◽  
Author(s):  
Andrew C. Stuart ◽  
John R. Tumbleston ◽  
Huaxing Zhou ◽  
Wentao Li ◽  
Shubin Liu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Polymer Solar Cells ◽  
Charge Recombination ◽  
Structure And Morphology ◽  
Morphology Development ◽  
Reduce Charge Recombination

Effects of GaN Thin Layer on InGaN at Electrolyte-Semiconductor Interface for the Application of Photoelectrochemical Water Splitting

2012 ◽  
Vol 1387 ◽  
Author(s):  
Katsushi Fujii ◽  
Kayo Koike ◽  
Mika Atsumi ◽  
Takashi Itoh ◽  
Takenari Goto ◽  
...  
Keyword(s):  
Visible Light ◽  
Water Splitting ◽  
Hydrogen Generation ◽  
Uv Light ◽  
Photocurrent Density ◽  
Crystal Quality ◽  
Band Edge ◽  
Tunneling Effect ◽  
Conduction Band Edge ◽  
Indium Composition

ABSTRACTPhotoelectrochemical properties of nitride semiconductors are paid attention due to their possibilities of water splitting by visible light absorption. However, the photocurrent density of InxGa1-xN, which absorbs visible light, is usually lower than that of GaN, which has larger band-gap and absorbing only UV light. The reasons of this are thought to be the band-edge position at the semiconductor-electrolyte interface and the crystal quality. The conduction band-edge decreases with increasing of indium composition and across the hydrogen generation energy at around the indium composition of 0.2. This means that the hydrogen generation ability decreases with increasing of indium composition. Low crystal quality is obtained because the lower growth temperature of InxGa1-xN than that of GaN to achieve the indium incorporation. In order to improve the photocurrent density, band-edge energy control and quantum tunneling effect are tried using the structure of thin GaN layer on InxGa1-xN here. The effect for the photocurrent densities is also discussed.

scholarly journals Strain-Tunable Visible-Light-Responsive Photocatalytic Properties of Two-Dimensional CdS/g-C3N4: A Hybrid Density Functional Study

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 244 ◽  
Author(s):  
Guangzhao Wang ◽  
Feng Zhou ◽  
Binfang Yuan ◽  
Shuyuan Xiao ◽  
Anlong Kuang ◽  
...  
Keyword(s):  
Visible Light ◽  
Density Functional ◽  
Hydrogen Generation ◽  
Ph Value ◽  
Band Edge ◽  
Functional Study ◽  
Two Dimensional ◽  
Biaxial Strain ◽  
Narrow Bandgap ◽  
Hybrid Density Functional

By means of a hybrid density functional, we comprehensively investigate the energetic, electronic, optical properties, and band edge alignments of two-dimensional (2D) CdS/g-C 3 N 4 heterostructures by considering the effect of biaxial strain and pH value, so as to improve the photocatalytic activity. The results reveal that a CdS monolayer weakly contacts with g-C 3 N 4 , forming a type II van der Waals (vdW) heterostructure. The narrow bandgap makes CdS/g-C 3 N 4 suitable for absorbing visible light and the induced built-in electric field between the interface promotes the effective separation of photogenerated carriers. Through applying the biaxial strain, the interface adhesion energy, bandgap, and band edge positions, in contrast with water, redox levels of CdS/g-C 3 N 4 can be obviously adjusted. Especially, the pH of electrolyte also significantly influences the photocatalytic performance of CdS/g-C 3 N 4 . When pH is smaller than 6.5, the band edge alignments of CdS/g-C 3 N 4 are thermodynamically beneficial for oxygen and hydrogen generation. Our findings offer a theoretical basis to develop g-C 3 N 4 -based water-splitting photocatalysts.

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