Simultaneous Intra- and Intermolecular Singlet Fission in Bipentacene Macrocycle Aggregates
Zhangxia Wang1, Xiaoyu Xie2, Haibo Ma2
1School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China.
The Journal of Physical Chemistry Letters
|March 24, 2024
Summary
Singlet fission (SF) in bipentacene macrocycles (BPc) thin films enhances intermolecular SF efficiency. Orderly crystal domains are not required for optimal device performance, enabling diverse device designs.
Area of Science:
- Photophysics and optoelectronics
- Materials science of organic semiconductors
Background:
- Singlet fission (SF) converts one singlet exciton into two triplet excitons, boosting optoelectronic device efficiency.
- Macrocyclic structures offer precise chromophore control in solution-based SF.
- SF behavior in thin films, critical for solid-state devices, is not well understood.
Purpose of the Study:
- To investigate the aggregation and SF properties of bipentacene macrocycles (BPc) in thin films.
- To correlate thin-film morphology with SF efficiency for device optimization.
Main Methods:
- Molecular dynamics (MD) simulations to model aggregation and film formation.
- Electronic structure calculations to determine SF rates (intramolecular and intermolecular).
Main Results:
- BPc exhibits faster aggregation and parallel alignment to the substrate with reduced solvent (chloroform).
- Intramolecular SF (iSF) rates remain largely unchanged during film evaporation.
- Intermolecular SF (xSF) efficiency increases due to enhanced packing domains.
Conclusions:
- Thin-film morphology significantly influences SF efficiency, particularly xSF.
- Highly ordered crystalline domains are not essential for efficient SF in devices.
- Findings support diverse device architectures and traditional solution-based fabrication methods for SF optimization.
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