biostudies-literatureHan TNatural Science Foundation of Hunan Province (Hunan Provincial Natural Science Foundation)National Natural Science Foundation of China (National Science Foundation of China)1332https://www.ebi.ac.uk/biostudies/studies/S-EPMC8917130biostudies-literatureUnknown13(1)The narrow bandgap of near-infrared (NIR) polymers is a major barrier to improving the performance of NIR phototransistors. The existing technique for overcoming this barrier is to construct a bilayer device (channel layer/bulk heterojunction (BHJ) layer). However, acceptor phases of the BHJ dissolve into the channel layer and are randomly distributed by the spin-coating method, resulting in turn-on voltages (V_o) and off-state dark currents remaining at a high level. In this work, a diffusion interface layer is formed between the channel layer and BHJ layer after treating the film transfer method (FTM)-based NIR phototransistors with solvent vapor annealing (SVA). The newly formed diffusion interface layer makes it possible to control the acceptor phase distribution. The performance of the FTM-based device improves after SVA. V_o decreases from 26 V to zero, and the dark currents decrease by one order of magnitude. The photosensitivity (I_ph/I_dark) increases from 22 to 1.7 × 10⁷.Nature communicationsDiffusion interface layer controlling the acceptor phase of bilayer near-infrared polymer phototransistors with ultrahigh photosensitivity.PMC89171302019JJ5056551801034, 5217206751873068, 51573055Liu LDing SShen NHuang XZhang XJiang CHou XHan TWang ZZhou ZfalseDiffusion interface layer controlling the acceptor phase of bilayer near-infrared polymer phototransistors with ultrahigh photosensitivity.The narrow bandgap of near-infrared (NIR) polymers is a major barrier to improving the performance of NIR phototransistors. The existing technique for overcoming this barrier is to construct a bilayer device (channel layer/bulk heterojunction (BHJ) layer). However, acceptor phases of the BHJ dissolve into the channel layer and are randomly distributed by the spin-coating method, resulting in turn-on voltages (V_o) and off-state dark currents remaining at a high level. In this work, a diffusion interface layer is formed between the channel layer and BHJ layer after treating the film transfer method (FTM)-based NIR phototransistors with solvent vapor annealing (SVA). The newly formed diffusion interface layer makes it possible to control the acceptor phase distribution. The performance of the FTM-based device improves after SVA. V_o decreases from 26 V to zero, and the dark currents decrease by one order of magnitude. The photosensitivity (I_ph/I_dark) increases from 22 to 1.7 × 10⁷.2022-01-01T00:00:00Z2022 Mar2025-04-18T15:07:30.203Z2025-04-07T01:43:46.788ZS-EPMC89171303527748610.1038/s41467-022-28922-4