Charge transfer from internal electrostatic fields is superior to surface defects for 2,4-dichlorophenol degradation in K3−xNaxB6O10Br photocatalysts

Nanoscale ◽  
2018 ◽  
Vol 10 (43) ◽  
pp. 20443-20452 ◽  
Author(s):  
Xiaoyun Fan ◽  
Yang Zhang ◽  
Kangdi Zhong
Keyword(s):  
Charge Transfer ◽  
Charge Separation ◽  
Driving Force ◽  
Surface Defects ◽  
Degradation Process ◽  
Electrostatic Fields

The driving force from the bulk could offer greater motivation for charge separation than from surface defects during 2,4-DCP degradation process.

scholarly journals The binding energy and dynamics of charge-transfer states in organic photovoltaics with low driving force for charge separation

2019 ◽  
Vol 150 (10) ◽  
pp. 104704 ◽  
Author(s):  
Yifan Dong ◽  
Hyojung Cha ◽  
Jiangbin Zhang ◽  
Ernest Pastor ◽  
Pabitra Shakya Tuladhar ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Binding Energy ◽  
Organic Photovoltaics ◽  
Charge Separation ◽  
Driving Force

The lowest-energy charge-transfer state and its role in charge separation in organic photovoltaics

2016 ◽  
Vol 18 (26) ◽  
pp. 17546-17556 ◽  
Author(s):  
Guangjun Nan ◽  
Xu Zhang ◽  
Gang Lu
Keyword(s):  
Charge Transfer ◽  
Quantum Efficiency ◽  
Charge Separation ◽  
Driving Force ◽  
Internal Quantum Efficiency ◽  
Energy Charge ◽  
Charge Transfer State ◽  
Dynamic Disorder ◽  
Configuration Entropy ◽  
Transfer State

The localized charge transfer state can lead to >90% internal quantum efficiency provided by the driving force from dynamic disorder and configuration entropy.

scholarly journals Colloidal CdSe nanocrystals are inherently defective

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tamar Goldzak ◽  
Alexandra R. McIsaac ◽  
Troy Van Voorhis
Keyword(s):  
Charge Transfer ◽  
Energy Spectrum ◽  
Surface Structure ◽  
Short Range ◽  
Surface Defects ◽  
Low Energy ◽  
Lewis Base ◽  
Cdse Nanocrystals ◽  
Photoinduced Charge Transfer ◽  
Photoinduced Charge

AbstractColloidal CdSe nanocrystals (NCs) have shown promise in applications ranging from LED displays to medical imaging. Their unique photophysics depend sensitively on the presence or absence of surface defects. Using simulations, we show that CdSe NCs are inherently defective; even for stoichiometric NCs with perfect ligand passivation and no vacancies or defects, we still observe that the low energy spectrum is dominated by dark, surface-associated excitations, which are more numerous in larger NCs. Surface structure analysis shows that the majority of these states involve holes that are localized on two-coordinate Se atoms. As chalcogenide atoms are not passivated by any Lewis base ligand, varying the ligand should not dramatically change the number of dark states, which we confirm by simulating three passivation schemes. Our results have significant implications for understanding CdSe NC photophysics, and suggest that photochemistry and short-range photoinduced charge transfer should be much more facile than previously anticipated.

scholarly journals Anion-enhanced excited state charge separation in a spiro-locked N-heterocycle-fused push-pull zinc porphyrin

2021 ◽  
Author(s):  
Mandeep K. Chahal ◽  
Anuradha Liyanage ◽  
Ajyal Z. Alsaleh ◽  
Paul A. Karr ◽  
Jonathan P. Hill ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Charge Separation ◽  
Charge Transfer Complex ◽  
Zinc Porphyrin ◽  
New Type ◽  
State Charge

A new type of push–pull charge transfer complex, viz., a spiro-locked N-heterocycle-fused zinc porphyrin, ZnP-SQ, is shown to undergo excited state charge separation, which is enhanced by axial F− binding to the Zn center.

scholarly journals Long-lived charge separation following pump-wavelength–dependent ultrafast charge transfer in graphene/WS2 heterostructures

2021 ◽  
Vol 7 (9) ◽  
pp. eabd9061
Author(s):  
Shuai Fu ◽  
Indy du Fossé ◽  
Xiaoyu Jia ◽  
Jingyin Xu ◽  
Xiaoqing Yu ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Charge Separation ◽  
Transient Absorption ◽  
Transition Metal Dichalcogenides ◽  
Thermionic Emission ◽  
Great Promise ◽  
Metal Dichalcogenides ◽  
Ultrafast Charge Transfer ◽  
Device Operation ◽  
Interfacial Charge

Van der Waals heterostructures consisting of graphene and transition metal dichalcogenides have shown great promise for optoelectronic applications. However, an in-depth understanding of the critical processes for device operation, namely, interfacial charge transfer (CT) and recombination, has so far remained elusive. Here, we investigate these processes in graphene-WS2 heterostructures by complementarily probing the ultrafast terahertz photoconductivity in graphene and the transient absorption dynamics in WS2 following photoexcitation. We observe that separated charges in the heterostructure following CT live extremely long: beyond 1 ns, in contrast to ~1 ps charge separation reported in previous studies. This leads to efficient photogating of graphene. Furthermore, for the CT process across graphene-WS2 interfaces, we find that it occurs via photo-thermionic emission for sub-A-exciton excitations and direct hole transfer from WS2 to the valence band of graphene for above-A-exciton excitations. These findings provide insights to further optimize the performance of optoelectronic devices, in particular photodetection.

ORGANIC CuPc COATING INDUCED IMPROVED PHOTOLUMINESCENCE AND PHOTOCONDUCTIVITY OF ZnO NANOWIRES ARRAY

2012 ◽  
Vol 05 (03) ◽  
pp. 1250021 ◽  
Author(s):  
SOUMEN DHARA ◽  
P. K. GIRI
Keyword(s):  
Charge Transfer ◽  
Dark Current ◽  
Surface Defects ◽  
Green Emission ◽  
Charge Transfer Process ◽  
Current Ratio ◽  
Uv Emission ◽  
Surface Covering ◽  
Interfacial Charge ◽  
Nanowires Array

In this work, we investigated the effect of organic CuPc coating on the surface of the ZnO NWs for possible improvement in the photoluminescence, photoconductivity and photoresponse. As a result of surface covering, the UV emission is enhanced by a factor of 7–8 while the green emission is reduced to half. Despite an increase in dark current after the CuPc covering, we obtained a significant improvement in the photocurrent and photoresponse rate. The photocurrent-to-dark current ratio is nearly doubled and the photoresponse process becomes faster for the ZnO/CuPc heterostructure. Improvements in the photoluminescence and photoconductivity for the ZnO/CuPc heterostructure are explained on the basis of modification of surface defects and interfacial charge transfer process.

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