An Efficient Narrowband Near?Infrared at 1040 nm Organic Photodetector Realized by Intermolecular Charge Transfer Mediated Coupling Based on a Squaraine Dye

A highly sensitive short-wave infrared (SWIR, ? > 1000 nm) organic photodiode (OPD) is described based on a well-organized nanocrystalline bulk-heterojunction (BHJ) active layer composed of dicyanovinyl-functionalized squaraine dye (SQ-H) donor material in combination with PC61BM. Through thermal annealing, dipolar SQ-H chromophores self-assemble nanoscale structure intermolecular charge transfer mediated coupling, resulting redshifted and narrow absorption band at 1040 nm as well enhanced carrier mobility. The optimized OPD exhibits an external quantum efficiency (EQE) 12.3% full-width half-maximum only 85 (815 cm?1) 1050 under 0 V, which the first efficient SWIR J-type aggregates. Photoplethysmography application for heart-rate monitoring successfully demonstrated flexible substrates without applying reverse bias, indicating potential OPDs short-range coupled aggregates low-power operating wearable applications.