Authors: Tao Han, Zejiang Wang, Ning Shen, Zewen Zhou, Xuehua Hou, Shufang Ding, Chunzhi Jiang, Xiaoyi Huang, Xiaofeng Zhang, Linlin Liu
Published: 2022-03-11
DOI: 10.1038/s41467-022-28922-4
Source: Full article
AbstractThe 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 (Vo) 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.Vodecreases from 26 V to zero, and the dark currents decrease by one order of magnitude. The photosensitivity (Iph/Idark) increases from 22 to 1.7 × 107.