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 Anion-Exchange-Mediated Internal Electric Field: Boosting Photogenerated Carrier Separation and Utilization

2020 ◽  
Author(s):  
Yadong Li ◽  
Tong Han ◽  
Xing Cao ◽  
Kaian Sun ◽  
Qing Peng ◽  
...  
Keyword(s):  
Electric Field ◽  
Separation Efficiency ◽  
Photogenerated Carrier ◽  
Internal Electric Field ◽  
Design And Optimization ◽  
Halide Anions ◽  
Valence Electrons ◽  
Simple Chemical ◽  
Carrier Separation ◽  
First Time

Abstract Constructing heterojunctions is a commonly used method for heterogeneous photocatalysts to modulate the internal electric field (IEF); however, this method suffers from narrow IEF distribution (primarily limited at the heterojunction interface) and long migration paths of photocarriers, and therefore results in suboptimal efficiencies in carrier separation and utilization. In this work, we report for the first time novel basic bismuth nitrate 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. A low exchange ratio (~10%) with halide anions (I–, Br–, Cl–) would give rise to a prominent elevation in carrier separation efficiency; for the reaction of photocatalytic oxidative coupling of benzylamine, the conversions over the modified catalysts are 1.6–2 times as high as that over pristine BOH. Benefiting from the unique crystal structure and the localization of valence electrons, the IEF intensity increases with the atomic number of introduced halide anions, leading to an enhanced efficiency of carrier separation and utilization. Our work here offers new insights into the design and optimization of semiconductor photocatalysts.

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.

Photogenerated-carrier separation along edge dislocation of WO3single-crystal nanoflower photoanode

2018 ◽  
Vol 6 (18) ◽  
pp. 8604-8611 ◽  
Author(s):  
Yuyu Bu ◽  
Jun Ren ◽  
Huawei Zhang ◽  
Dongjiang Yang ◽  
Zhuoyuan Chen ◽  
...  
Keyword(s):  
Edge Dislocation ◽  
Separation Efficiency ◽  
Photogenerated Carrier ◽  
Crystal Face ◽  
Carrier Separation

Edge dislocation on WO3nanosheet can induce a crystal face heterojunction system to promote the separation efficiency of photogenerated carrier.

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 Photoreduction route for Cu2O/TiO2 nanotubes junction for enhanced photocatalytic activity

RSC Advances ◽  
2018 ◽  
Vol 8 (22) ◽  
pp. 12420-12427 ◽  
Author(s):  
Van Viet Pham ◽  
Dai Phat Bui ◽  
Hong Huy Tran ◽  
Minh Thi Cao ◽  
Tri Khoa Nguyen ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Electric Field ◽  
Tio2 Nanotubes ◽  
Photocatalytic Performance ◽  
Internal Electric Field ◽  
Lower Power ◽  
Uv Lamp ◽  
Good Photocatalytic Performance

Good photocatalytic performance is demonstrated by Cu2O NPs directly loaded onto hydrothermally synthesized TiO2 NTs via photoreduction method conducted with a lower power UV lamp at room temp. This is due to narrowing bandgap and forming an internal electric field.

scholarly journals A facile synthesis of Zn-doped TiO2 nanoparticles with highly exposed (001) facets for enhanced photocatalytic performance

RSC Advances ◽  
2021 ◽  
Vol 11 (13) ◽  
pp. 7627-7632
Author(s):  
Kun Jiang ◽  
Jin Zhang ◽  
Rui Luo ◽  
Yingfei Wan ◽  
Zengjian Liu ◽  
...  
Keyword(s):  
Visible Light ◽  
Tio2 Nanoparticles ◽  
Light Absorption ◽  
Photocatalytic Performance ◽  
Separation Efficiency ◽  
Absorption Capacity ◽  
Facile Synthesis ◽  
Visible Light Absorption ◽  
Doped Tio2 ◽  
Carrier Separation

It is a great challenge to simultaneously improve the visible light absorption capacity and enhance photon-generated carrier separation efficiency of photocatalysts.

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