Improved electrical ideality and photoresponse in near-infrared phototransistors realized by bulk heterojunction channels

Ning Li; Yanlian Lei; Yanqin Miao; Furong Zhu

doi:10.1016/j.isci.2021.103711

Improved electrical ideality and photoresponse in near-infrared phototransistors realized by bulk heterojunction channels

iScience. 2021 Dec 30;25(1):103711. doi: 10.1016/j.isci.2021.103711. eCollection 2022 Jan 21.

Authors

Ning Li¹, Yanlian Lei^{1

2}, Yanqin Miao^{1

3}, Furong Zhu¹

Affiliations

¹ Department of Physics, Research Centre of Excellence for Organic Electronics, and Institute of Advanced Materials, Hong Kong Baptist University, Hong Kong, China.
² School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
³ Key Laboratory of Interface Science and Engineering in Advanced Materials of Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China.

Abstract

The factors that affect the electrical ideality and photoresponse in near-infrared (NIR) organic phototransistors (OPTs) are still nebulous. Here, simultaneous increase in electrical ideality and NIR response in the OPTs is realized by applying a bulk heterojunction (BHJ) channel. The acceptor in the channel helps to trap the undesirable injected electrons, avoiding the accumulation of the electrons at the active channel/dielectric interface, and thereby improving the hole transporting. Use of a BHJ channel also helps reducing the contact resistance in the OPTs. The electrical stability is then improved with mitigated dependence of charge mobility on gate voltage in the saturation region. The BHJ channel also offers an improved photoresponse through enhanced exciton dissociation, leading to more than one order of magnitude increase in responsivity than that in a control OPT. The results are encouraging, which pave the way for the development of high-performing NIR OPTs.

Keywords: Electronic engineering; Electronic materials; Optical Materials; Optoelectronics.