Diffusion interface layer controlling the acceptor phase of bilayer near-infrared polymer phototransistors with ultrahigh photosensitivity.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35277486.
- Also identified by DOI 10.1038/s41467-022-28922-4 and PMC identifier 8917130.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
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<sub>o</sub>) 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<sub>o</sub> decreases from 26 V to zero, and the dark currents decrease by one order of magnitude. The photosensitivity (I<sub>ph</sub>/I<sub>dark</sub>) increases from 22 to 1.7 × 10<sup>7</sup>.