Green-Solvent-Processed\nHigh-Performance Broadband\nOrganic Photodetectors

Abstract

Solution-processed\norganic photodetectors with broadband activity\nhave been demonstrated with an environmentally benign solvent, <i>ortho</i>-xylene (<i>o</i>-xylene), as the processing\nsolvent. The organic photodetectors employ a wide band gap polymer\ndonor PBDB-T and a narrow band gap small-molecule non-fullerene acceptor\nCO1-4F, both dissolvable in <i>o</i>-xylene at a controlled\ntemperature. The <i>o</i>-xylene-processed devices have\nshown external quantum efficiency of up to 70%, surpassing the counterpart\nprocessed with chlorobenzene. With a well-suppressed dark current,\nthe device can also present a high specific detectivity of over 10¹² Jones at −2 V within practical operation frequencies\nand is applicable for photoplethysmography with its fast response.\nThese results further highlight the potential of green-solvent-processed\norganic photodetectors as a high-performing alternative to their counterparts\nprocessed in toxic chlorinated solvents without compromising the excellent\nphotosensing performance.