Interplay Between Triplet-, Singlet-Charge Transfer States and Free Charge Carriers Defining Bimolecular Recombination Rate Constant of Organic Solar Cells

2017 ◽  
Vol 121 (25) ◽  
pp. 13969-13976 ◽  
Author(s):  
Ardalan Armin ◽  
James R. Durrant ◽  
Safa Shoaee
Keyword(s):  
Solar Cells ◽  
Charge Transfer ◽  
Rate Constant ◽  
Organic Solar Cells ◽  
Recombination Rate ◽  
Charge Carriers ◽  
Free Charge ◽  
Bimolecular Recombination ◽  
Recombination Rate Constant

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.

scholarly journals Experimental Evidence Relating Charge-Transfer-State Kinetics and Strongly Reduced Bimolecular Recombination in Organic Solar Cells

2020 ◽  
Vol 11 (24) ◽  
pp. 10519-10525
Author(s):  
Nasim Zarrabi ◽  
Oskar J. Sandberg ◽  
Christina Kaiser ◽  
Jegadesan Subbiah ◽  
David J. Jones ◽  
...  
Keyword(s):  
Solar Cells ◽  
Charge Transfer ◽  
Experimental Evidence ◽  
Organic Solar Cells ◽  
Charge Transfer State ◽  
Bimolecular Recombination ◽  
Transfer State

scholarly journals Organic Solar Cells with Boron- or Nitrogen-Doped Carbon Nanotubes in the P3HT : PCBM Photoactive Layer

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Godfrey Keru ◽  
Patrick G. Ndungu ◽  
Genene T. Mola ◽  
Ana F. Nogueira ◽  
Vincent O. Nyamori
Keyword(s):  
Carbon Nanotubes ◽  
Solar Cells ◽  
Organic Solar Cells ◽  
Acid Methyl Ester ◽  
Charge Carriers ◽  
Spectroscopic Techniques ◽  
Free Charge ◽  
Photoactive Layer ◽  
Nitrogen Doped ◽  
Nitrogen Doped Carbon

Either boron- or nitrogen-doped carbon nanotubes (B- or N-CNTs) were incorporated in bulk heterojunction organic solar cells photoactive layer composed of poly(3-hexylthiophene) (P3HT) : (6,6)-phenyl-C61-butyric acid methyl ester (PCBM). The physical and chemical properties were investigated using different spectroscopic techniques. The cell performance was followed from their current-voltage (J-V) characteristics. Recombination dynamics of the photo-generated free charge carriers were investigated using micro- to milliseconds transient absorption spectroscopy (TAS). Transmission electron microscopy (TEM) images revealed the presence of cone structures and bamboo compartments in B-CNTs and N-CNTs, respectively. X-ray photoelectron spectroscopy (XPS) revealed very little boron was substituted in the carbon network and presence of pyrrolic, pyridinic, and quaternary species of nitrogen in N-CNTs.J-Vcharacteristics were found to be similar for the devices with B- and N-CNTs even though boron- and nitrogen-doped CNTs are known to have different properties, that is, p-type and n-type, respectively. TAS results showed that all devices had long lived free charge carriers but the devices with B- or N-CNTs had low power conservation efficiency and voltage.

The Cost of Converting Excitons into Free Charge Carriers in Organic Solar Cells

2019 ◽  
Vol 11 (1) ◽  
pp. 129-135 ◽  
Author(s):  
Koen Vandewal ◽  
Sigurd Mertens ◽  
Johannes Benduhn ◽  
Quan Liu
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
Charge Carriers ◽  
Free Charge ◽  
The Cost

Additive-induced Miscibility Regulation and Hierarchical Morphology Enables 17.5% Binary Organic Solar Cells

2021 ◽  
Author(s):  
Jie Lv ◽  
Hua Tang ◽  
Jiaming Huang ◽  
Cenqi Yan ◽  
Kuan Liu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Organic Solar Cells ◽  
Organic Solar Cell ◽  
Power Conversion ◽  
Charge Trapping ◽  
Free Charge ◽  
Charge Generation ◽  
Low Charge ◽  
Hierarchical Morphology

Due to the barrierless free charge generation, low charge trapping, and high charge mobilities, the PM6:Y6 organic solar cell (OSC) achieves excellent power conversion efficiency (PCE) of 15.7%. However, the...

Unraveling the Temperature Dependence of Exciton Dissociation and Free Charge Generation in Nonfullerene Organic Solar Cells

Solar RRL ◽  
2021 ◽  
Vol 5 (4) ◽  
pp. 2000789
Author(s):  
Chao Ma ◽  
Christopher C. S. Chan ◽  
Xinhui Zou ◽  
Han Yu ◽  
Jianquan Zhang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Temperature Dependence ◽  
Organic Solar Cells ◽  
Free Charge ◽  
Exciton Dissociation ◽  
Charge Generation
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