Ultrafast dynamics of the liquid deposited blend film of porphyrin donor and perylene diimide acceptor

Porphyrin and perylene diimide have great application potential in organic optoelectronic devices. However, large plane frames of porphyrin and PDI tend to aggregate, resulting in low power conversion efficiency. In this work, four side chain modified porphyrins (H2TCPP, ZnTCPP, H2TCPP(CH3)4, ZnTCPP(CH3)(4)), and one per-ylene diimide (PDI-C5) were synthesized. The blended films of the donor and acceptor were prepared by a simple and low-cost liquid deposition method. Femtosecond transient absorption spectroscopy and global analysis revealed that ZnTCPP(CH3)(4):PDI-C5 showed a higher rate of charge transfer and radical ions formation compared to the other porphyrin donors, which means that the ZnTCPP(CH3)(4) has good compatibility with PDI-C5. In addition, we also characterized these blended films by ultraviolet-visible absorption spectroscopy, cyclic voltammetry (CV), and AFM techniques. The CV results show that the difference between the LUMO of each porphyrin donor and PDI-C5 acceptor is about 0.3 eV, which is sufficient for exciton dissociation.

Automated summary

The study demonstrated that ZnTCPP(CH3)(4) modified with side chains showed better performance in charge transfer and radical ions formation with PDI-C5, indicating good compatibility. Additionally, cyclic voltammetry analysis revealed that the difference in LUMO between each porphyrin donor and PDI-C5 acceptor is sufficient for exciton dissociation.