scholarly journals Preparation of Novel ZnO/Cu2O Heterojunctions Composite Film by Codeposition Method and Their Enhanced Photocatalytic Performance Analysis

2021 ◽  
Author(s):  
xiaojiao yu ◽  
Qinggong Ji ◽  
Yuchen Wei ◽  
Zongbin Liu ◽  
Ningning Zhao ◽  
...  
Keyword(s):  
Fermi Level ◽  
Composite Film ◽  
Photocatalytic Performance ◽  
Open Circuit ◽  
Significant Shift ◽  
Photogenerated Carrier ◽  
Internal Electric Field ◽  
Dye Pollutants ◽  
Photoelectric Properties ◽  
Cu2o Film

Abstract IIn this paper, a codeposition method is used to prepare ZnO/Cu2O composite film with a heterojunction structure in one step. The microstructure and photoelectric properties of the prepared ZnO/Cu2O composite film are characterized and analyzed, and its photocatalytic performance is evaluated. Compared with pure the Cu2O film, the composite film exposes more (111) crystal planes, and has a smaller impedance and a larger photocurrent and open circuit voltage value. These findings indicate that the ZnO/Cu2O composite film exhibits excellent photogenerated carrier separation and migration efficiencies. Among the prepared samples, M2 demonstrates the highest photocatalytic and recycling performance. The calculation of the band position shows that the Fermi level of the composite film exhibits a significant shift compared to that of the pure Cu2O film. The analysis shows that the decrease in the recombination probability of photogenerated carriers caused by the shift of the Fermi level and formation of an internal electric field is the main factor for the significant enhancement in the Cu2O photocatalytic performance. This article provides a novel method and idea to realize the efficient removal of organic dye pollutants in sewage.

scholarly journals Anion-exchange-mediated internal electric field for boosting photogenerated carrier separation and utilization

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tong Han ◽  
Xing Cao ◽  
Kaian Sun ◽  
Qing Peng ◽  
Chenliang Ye ◽  
...  
Keyword(s):  
Electric Field ◽  
Photocatalytic Performance ◽  
Separation Efficiency ◽  
Photogenerated Carrier ◽  
Internal Electric Field ◽  
Design And Optimization ◽  
Halide Anions ◽  
Valence Electrons ◽  
Simple Chemical ◽  
Carrier Separation

AbstractHeterojunctions modulated internal electric field (IEF) usually result in suboptimal efficiencies in carrier separation and utilization because of the narrow IEF distribution and long migration paths of photocarriers. In this work, we report distinctive bismuth oxyhydroxide compound nanorods (denoted as BOH NRs) featuring surface-exposed open channels and a simple chemical composition; by simply modifying the bulk anion layers to overcome the limitations of heterojunctions, the bulk IEF could be readily modulated. Benefiting from the unique crystal structure and the localization of valence electrons, the bulk IEF intensity increases with the atomic number of introduced halide anions. Therefore, A low exchange ratio (~10%) with halide anions (I–, Br–, Cl–) gives rise to a prominent elevation in carrier separation efficiency and better photocatalytic performance for benzylamine coupling oxidation. Here, our work offers new insights into the design and optimization of semiconductor photocatalysts.

scholarly journals On the Relation between the Open‐Circuit Voltage and Quasi‐Fermi Level Splitting in Efficient Perovskite Solar Cells

2019 ◽  
Vol 9 (33) ◽  
pp. 1901631 ◽  
Author(s):  
Pietro Caprioglio ◽  
Martin Stolterfoht ◽  
Christian M. Wolff ◽  
Thomas Unold ◽  
Bernd Rech ◽  
...  
Keyword(s):  
Solar Cells ◽  
Fermi Level ◽  
Open Circuit Voltage ◽  
Perovskite Solar Cells ◽  
Open Circuit ◽  
Quasi Fermi Level ◽  
Level Splitting

scholarly journals Investigation of the Carrier Movement through the Tunneling Junction in the InGaP/GaAs Dual Junction Solar Cell Using the Electrically and Optically Biased Photoreflectance Spectroscopy

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 638
Author(s):  
Sanam SaeidNahaei ◽  
Hyun-Jun Jo ◽  
Sang Jo Lee ◽  
Jong Su Kim ◽  
Sang Jun Lee ◽  
...  
Keyword(s):  
Solar Cell ◽  
Electric Field ◽  
Electric Fields ◽  
Bias Voltage ◽  
Tunnel Junction ◽  
Photogenerated Carrier ◽  
Internal Electric Field ◽  
Junction Solar Cell ◽  
Photoreflectance Spectroscopy ◽  
Dc Bias

For examining the carrier movements through tunnel junction, electrically and optically-biased photoreflectance spectroscopy (EBPR and OBPR) were used to investigate the internal electric field in the InGaP/GaAs dual junction solar cell at room temperature. At InGaP and GaAs, the strength of p-n junction electric fields (Fpn) was perturbed by the external DC bias voltage and CW light intensity for EBPR and OBPR experiments, respectively. Moreover, the Fpn was evaluated using the Fast Fourier Transform (FFT) of the Franz—Keldysh oscillation from PR spectra. In the EBPR, the electric field decreased by increasing the DC bias voltage, which also decreased the potential barrier. In OBPR, when incident CW light is absorbed by the top cell, the decrement of the Fpn in the GaAs cell indicates that the photogenerated carriers are accumulated near the p-n junction. Photogenerated carriers in InGaP can pass through the tunnel junction, and the PR results show the contribution of the modification of the electric field by the photogenerated carriers in each cell. We suggest that PR spectroscopy with optical-bias and electrical-bias could be analyzed using the information of the photogenerated carrier passed through the tunnel junction.

Self Powered Flexible Electronics Based on Self Poled “Ferroelectretic” Nanogenerator

MRS Advances ◽  
2016 ◽  
Vol 1 (45) ◽  
pp. 3083-3088 ◽  
Author(s):  
Sujoy Kumar Ghosh ◽  
Dipankar Mandal
Keyword(s):  
Composite Film ◽  
Flexible Electronics ◽  
Light Emitting Diode ◽  
Open Circuit ◽  
Pvdf Film ◽  
Light Emitting ◽  
Single Finger ◽  
Finger Touch ◽  
Self Powered ◽  
Pure Pvdf

ABSTRACTA ferroelectric nanogenerator without any electric poling treatment has been realized by incorporation of ytterbium (Yb) salt incorporated porous PVDF composite film. The composite film compose of electroactive β- and γ-phases, demonstrates higher dielectric and ferroelectric polarization responses than pure PVDF film. The 3 V of open circuit voltage with 0.47 µW/cm2 power density was generated by the nanogenerator upon single finger touch. It can also operate capacitor and light emitting diode without any subsidiary batteries.

Cu2O Film via Hydrothermal Redox Approach: Morphology and Photocatalytic Performance

2013 ◽  
Vol 118 (30) ◽  
pp. 16335-16343 ◽  
Author(s):  
Lun Pan ◽  
Ji-Jun Zou ◽  
Tierui Zhang ◽  
Songbo Wang ◽  
Zhe Li ◽  
...  
Keyword(s):  
Photocatalytic Performance ◽  
Cu2o Film

Fermi level pinning or semiconductor electrodes in aqueous and non aqueous electrolytes: influence of the modification of the electrode surface

1989 ◽  
Vol 67 (3) ◽  
pp. 382-388 ◽  
Author(s):  
O. Savadogo
Keyword(s):  
Fermi Level ◽  
Acidic Medium ◽  
Open Circuit ◽  
Flat Band ◽  
Flat Band Potential ◽  
Fermi Level Pinning ◽  
Material Surfaces ◽  
Electrolyte Interface ◽  
Semiconductor Electrodes ◽  
Minority Carriers

Modification of several semiconductors material surfaces with H4SiW12O40•nH2O have been carried out to produce an increase in the open circuit photopotential at the semiconductor/electrolyte interface (Voc) without changing the flat-band potential. The augmentation of Voc is shown to be attributed to a decrease of the minority carriers recombination at the semiconductor/electrolyte interface along with the suppression of Fermi level pinning. The enhancement of Voc and the electrocatalytic activity of the hydrogen evolution reaction in acidic medium of the derivatized electrodes is attributed to the Fermi level unpinning. Keywords: photoelectrodes, photoelectrocatalysis, pinning, modification improvement.

scholarly journals Nonequilibrium site distribution governs charge-transfer electroluminescence at disordered organic heterointerfaces

2019 ◽  
Vol 116 (47) ◽  
pp. 23416-23425 ◽  
Author(s):  
Armantas Melianas ◽  
Nikolaos Felekidis ◽  
Yuttapoom Puttisong ◽  
Stefan C. J. Meskers ◽  
Olle Inganäs ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Light Emission ◽  
Kinetic Monte Carlo ◽  
Light Emitting Diode ◽  
Open Circuit ◽  
Photogenerated Carrier ◽  
Weak Current ◽  
3 Dimensional ◽  
Site Distribution ◽  
Reciprocity Relations

The interface between electron-donating (D) and electron-accepting (A) materials in organic photovoltaic (OPV) devices is commonly probed by charge-transfer (CT) electroluminescence (EL) measurements to estimate the CT energy, which critically relates to device open-circuit voltage. It is generally assumed that during CT-EL injected charges recombine at close-to-equilibrium energies in their respective density of states (DOS). Here, we explicitly quantify that CT-EL instead originates from higher-energy DOS site distributions significantly above DOS equilibrium energies. To demonstrate this, we have developed a quantitative and experimentally calibrated model for CT-EL at organic D/A heterointerfaces, which simultaneously accounts for the charge transport physics in an energetically disordered DOS and the Franck–Condon broadening. The 0–0 CT-EL transition lineshape is numerically calculated using measured energetic disorder values as input to 3-dimensional kinetic Monte Carlo simulations. We account for vibrational CT-EL overtones by selectively measuring the dominant vibrational phonon-mode energy governing CT luminescence at the D/A interface using fluorescence line-narrowing spectroscopy. Our model numerically reproduces the measured CT-EL spectra and their bias dependence and reveals the higher-lying manifold of DOS sites responsible for CT-EL. Lowest-energy CT states are situated ∼180 to 570 meV below the 0–0 CT-EL transition, enabling photogenerated carrier thermalization to these low-lying DOS sites when the OPV device is operated as a solar cell rather than as a light-emitting diode. Nonequilibrium site distribution rationalizes the experimentally observed weak current-density dependence of CT-EL and poses fundamental questions on reciprocity relations relating light emission to photovoltaic action and regarding minimal attainable photovoltaic energy conversion losses in OPV devices.

scholarly journals A “concentration-induced self-assembly” strategy for AgxH3−xPMo12O40 nanorods: synthesis, photoelectric properties and photocatalytic applications

2021 ◽  
Author(s):  
Xinxin Wang ◽  
Yuting Song ◽  
Fengyan Li ◽  
Wenjuan Xu ◽  
Yue Zheng ◽  
...  
Keyword(s):  
Self Assembly ◽  
Photocatalytic Performance ◽  
Assembly Strategy ◽  
Photoelectric Properties ◽  
Photocatalytic Applications

Pristine polyoxometalate AgHPMo12 nanorods have been successfully synthesized, and a nanorods/phthalocyanine photocatalyst was also prepared to show an efficient photocatalytic performance.

scholarly journals Ag as Cocatalyst and Electron-Hole Medium in CeO2 QDs/Ag/Ag2Se Z-scheme Heterojunction Enhanced the Photo-Electrocatalytic Properties of the Photoelectrode

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 253 ◽  
Author(s):  
Lingwei Li ◽  
Hange Feng ◽  
Xiaofan Wei ◽  
Kun Jiang ◽  
Shaolin Xue ◽  
...  
Keyword(s):  
High Speed ◽  
Oxygen Vacancies ◽  
Photocatalytic Performance ◽  
Interfacial Region ◽  
Photogenerated Carrier ◽  
Electron Hole ◽  
Carrier Recombination ◽  
Photocatalytic System ◽  
Nano Channel ◽  
Active Substances

A recyclable photoelectrode with high degradation capability for organic pollutants is crucial for environmental protection and, in this work, a novel CeO2 quantum dot (QDs)/Ag2Se Z-scheme photoelectrode boasting increased visible light absorption and fast separation and transfer of photo-induced carriers is prepared and demonstrated. A higher voltage increases the photocurrent and 95.8% of tetracycline (TC) is degraded by 10% CeO2 QDs/Ag2Se in 75 minutes. The degradation rate is superior to that achieved by photocatalysis (92.3% of TC in 90 min) or electrocatalysis (27.7% of TC in 90 min). Oxygen vacancies on the CeO2 QDs advance the separation and transfer of photogenerated carriers at the interfacial region. Free radical capture tests demonstrate that •O2−, •OH, and h+ are the principal active substances and, by also considering the bandgaps of CeO2 QDs and Ag2Se, the photocatalytic mechanism of CeO2 QDs/Ag2Se abides by the Z-scheme rather than the traditional heterojunction scheme. A small amount of metallic Ag formed in the photocatalysis process can form a high-speed charge transfer nano channel, which can greatly inhibit the photogenerated carrier recombination, improve the photocatalytic performance, and help form a steady Z-scheme photocatalysis system. This study would lay a foundation for the design of a Z-scheme solar photocatalytic system.

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