Nature of Local Charge Carrier Motions in Porphyrin-Based Bulk Heterojunction Films Revealed by Time-Resolved Optical Pump-Terahertz Probe Spectroscopy

2021 ◽  
Author(s):  
Kaoru Ohta ◽  
Yuichi Hiramatsu ◽  
Mitsuharu Suzuki ◽  
Hiroko Yamada ◽  
Keisuke Tominaga
2019 ◽  
Author(s):  
Hannes Hempel ◽  
Andrei Petsiu ◽  
Martin Stolterfoht ◽  
Pascal Becker ◽  
Dieter Neher ◽  
...  

Nanoscale ◽  
2021 ◽  
Author(s):  
Mithun K P ◽  
Srabani Kar ◽  
Abinash Kumar ◽  
Victor Suvisesha Muthu Dharmaraj ◽  
Ravishankar Narayanan ◽  
...  

Collective excitation of Dirac plasmons in graphene and topological insulators have opened new possibilities of tunable plasmonic materials ranging from THz to mid-infrared regions. Using time resolved Optical Pump -...


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Silvia G. Motti ◽  
Jay B. Patel ◽  
Robert D. J. Oliver ◽  
Henry J. Snaith ◽  
Michael B. Johnston ◽  
...  

AbstractMixed halide perovskites can provide optimal bandgaps for tandem solar cells which are key to improved cost-efficiencies, but can still suffer from detrimental illumination-induced phase segregation. Here we employ optical-pump terahertz-probe spectroscopy to investigate the impact of halide segregation on the charge-carrier dynamics and transport properties of mixed halide perovskite films. We reveal that, surprisingly, halide segregation results in negligible impact to the THz charge-carrier mobilities, and that charge carriers within the I-rich phase are not strongly localised. We further demonstrate enhanced lattice anharmonicity in the segregated I-rich domains, which is likely to support ionic migration. These phonon anharmonicity effects also serve as evidence of a remarkably fast, picosecond charge funnelling into the narrow-bandgap I-rich domains. Our analysis demonstrates how minimal structural transformations during phase segregation have a dramatic effect on the charge-carrier dynamics as a result of charge funnelling. We suggest that because such enhanced recombination is radiative, performance losses may be mitigated by deployment of careful light management strategies in solar cells.


ACS Nano ◽  
2015 ◽  
Vol 9 (12) ◽  
pp. 12004-12010 ◽  
Author(s):  
Srabani Kar ◽  
Y. Su ◽  
R. R. Nair ◽  
A. K. Sood

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