Molecular-Device Co-Engineering of Ultra-Low Dark Current SWIR Organic Photodetectors for High-Quality Blood-Pressure Monitoring and Optical Communication.

The limited noise-responsivity balance in Short-wave infrared (SWIR) organic photodetectors (OPDs) restricts their biomedical and optoelectronic applications. In this study, this challenge is addressed through molecular-device co-engineering by designing two fluorinated narrow-bandgap non-fullerene acceptors (BTT-DTPn and BTT-DTPn-2F) coupled with solvent vapor annealing (SVA), achieving low noise and high detectivity in SWIR OPDs. The optimized devices based on BTT-DTPn-2F, which features enhance π-π stacking due to terminal fluorination, extend its absorption capability to 1300 nm.