scholarly journals Impact of quantized vibrations on the efficiency of interfacial charge separation in photovoltaic devices

2015 ◽  
Vol 91 (4) ◽  
Author(s):  
Soumya Bera ◽  
Nicolas Gheeraert ◽  
Simone Fratini ◽  
Sergio Ciuchi ◽  
Serge Florens
Keyword(s):  
Charge Separation ◽  
Photovoltaic Devices ◽  
Interfacial Charge

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.

scholarly journals Long-lived and disorder-free charge transfer states enable endothermic charge separation in efficient non-fullerene organic solar cells

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Ture F. Hinrichsen ◽  
Christopher C. S. Chan ◽  
Chao Ma ◽  
David Paleček ◽  
Alexander Gillett ◽  
...  
Keyword(s):  
Solar Cells ◽  
Charge Transfer ◽  
Organic Solar Cells ◽  
Charge Separation ◽  
Free Charge ◽  
Charge Generation ◽  
Time Resolved ◽  
Thermodynamic Conditions ◽  
Donor Acceptor ◽  
Interfacial Charge

Abstract Organic solar cells based on non-fullerene acceptors can show high charge generation yields despite near-zero donor–acceptor energy offsets to drive charge separation and overcome the mutual Coulomb attraction between electron and hole. Here, we use time-resolved optical spectroscopy to show that free charges in these systems are generated by thermally activated dissociation of interfacial charge-transfer states that occurs over hundreds of picoseconds at room temperature, three orders of magnitude slower than comparable fullerene-based systems. Upon free electron–hole encounters at later times, both charge-transfer states and emissive excitons are regenerated, thus setting up an equilibrium between excitons, charge-transfer states and free charges. Our results suggest that the formation of long-lived and disorder-free charge-transfer states in these systems enables them to operate closely to quasi-thermodynamic conditions with no requirement for energy offsets to drive interfacial charge separation and achieve suppressed non-radiative recombination.

An Efficient Strategy for Boosting Photogenerated Charge Separation by Using Porphyrins as Interfacial Charge Mediators

2019 ◽  
Vol 131 (47) ◽  
pp. 16956-16961 ◽  
Author(s):  
Xingming Ning ◽  
Bingzhang Lu ◽  
Zhen Zhang ◽  
Peiyao Du ◽  
Hongxia Ren ◽  
...  
Keyword(s):  
Charge Separation ◽  
Efficient Strategy ◽  
Photogenerated Charge Separation ◽  
Interfacial Charge

scholarly journals Interfacial charge separation in Cu2O/RuOx as a visible light driven CO2 reduction catalyst

2014 ◽  
Vol 16 (13) ◽  
pp. 5922-5926 ◽  
Author(s):  
Ernest Pastor ◽  
Federico M. Pesci ◽  
Anna Reynal ◽  
Albertus D. Handoko ◽  
Mingjia Guo ◽  
...  
Keyword(s):  
Visible Light ◽  
Absorption Spectroscopy ◽  
Charge Separation ◽  
Transient Absorption ◽  
Co2 Reduction ◽  
Charge Carriers ◽  
Transient Absorption Spectroscopy ◽  
Visible Light Driven ◽  
Interfacial Charge

Transient absorption spectroscopy as a tool to monitor charge carriers in Cu2O–RuOx photocathodes for CO2 reduction.

Interfacial Charge Separation and Recombination in InP and Quasi-Type II InP/CdS Core/Shell Quantum Dot-Molecular Acceptor Complexes

2013 ◽  
Vol 117 (32) ◽  
pp. 7561-7570 ◽  
Author(s):  
Kaifeng Wu ◽  
Nianhui Song ◽  
Zheng Liu ◽  
Haiming Zhu ◽  
William Rodríguez-Córdoba ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Charge Separation ◽  
Core Shell ◽  
Type Ii ◽  
Interfacial Charge

scholarly journals Enhanced photoelectrochemical water splitting performance using morphology-controlled BiVO4 with W doping

2017 ◽  
Vol 8 ◽  
pp. 2640-2647 ◽  
Author(s):  
Xin Zhao ◽  
Zhong Chen
Keyword(s):  
Surface Area ◽  
Light Absorption ◽  
Charge Separation ◽  
High Surface ◽  
High Surface Area ◽  
Charge Injection ◽  
Volume Ratio ◽  
Solvent Ratio ◽  
Photoelectrochemical Performance ◽  
Interfacial Charge

Nanostructures exhibit numerous merits to improve the efficiency in solar-to-energy conversion. These include shortened carrier collection pathways, an increased volume ratio between depletion layer and bulk, enhanced light capture due to multiple light scattering in nanostructures, and a high surface area for photochemical conversion reactions. In this study, we describe the synthesis of morphology-controlled W-doped BiVO4 by simply tuning the solvent ratio in precursor solutions. Planar and porous W-doped BiVO4 thin films were prepared and compared. The porous film, which exhibits increased surface area and enhanced light absorption, has displayed enhanced charge separation and interfacial charge injection. Our quantitative analysis showed an enhancement of about 50% of the photoelectrochemical performance for the porous structure compared to the planar structure. This enhancement is attributed to improved light absorption (13% increase), charge separation (14% increase), and interfacial charge injection (20% increase).

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