Research on Donor-Mixing-Acceptor Sandwich-Structured Organic Photodetectors Based on the “Sponge Permeation” Model

Organic photodetectors (OPDs) have garnered significant attention due to their cost-effectiveness, high optical absorption coefficients, solution processability, energy-efficient production methods, exceptional mechanical flexibility, and customizable spectral responses. However, noise suppression has consistently presented a great challenge for the development of the use of OPDs. This study introduces the "sponge permeation" model, which facilitates the fabrication of distinct donor-mix-acceptor (D-m-A) sandwich-structured OPDs through sequential deposition techniques. The resulting D-m-A structure significantly suppresses the noise current and shortens the charge transfer paths, leading to pseudoplanar heterojunction (PPHJ) OPDs that exhibit higher detectivity (6.81 × 1012 Jones) and faster response speeds (0.59/0.73 μs) compared to conventional bulk heterojunction (BHJ) OPDs. Furthermore, the PPHJ devices exhibited greater stability than the BHJ devices, maintaining 90% of their original performance after 30 days of storage in nitrogen. Notably, the acceptor material can be easily separated from the PPHJ film, enabling a straightforward recycling process that can reduce the costs associated with the manufacture of organic electronic devices.