Large-scale Roll-to-Roll Micro-gravure Printed Flexible PBDB-T/IT-M Bulk Heterojunction Photodetectors

Abstract

Printed electronics enable the fabrication of large-scale, low-cost electronic devices and systems and thus offer significant possibilities in terms of developing new optoelectronic application in various fields. Organic photodetectors (OPDs) represent an emerging organic optoelectronic device, which have attracted extensive attention due to many advantages such as low cost, mechanical flexibility and chemical tailoring. Herein, flexible bulk heterojunction (BHJ) OPDs are fabricated on polyethylene terephthalate (PET) substrate by large-scale roll-to-roll (R2R) micro-gravure printing technique using the novel printable ink, which consists of a conjugated polymer named PBDB-T and a nonfullerene small molecule named IT-M. The device photoresponse covers the range from ultraviolet (UV) to visible light (Vis). Meanwhile, OPDs show a high photoresponsivity (R) up to 4.18 A/W and a good detectivity (D*) as high as 1.11 × 1011 Jones. Under the different bending curvature or after being bent 5000 times, the flexible OPDs still well maintain the performance parameters. Furthermore, the large-area OPD arrays exhibit good uniformity and high stability in atmospheric conditions without any encapsulation for 40 days. This work reports the high-quality PBDB-T/IT-M BHJ used for UV–Vis photodetectors, which provides an innovation pathway to develop high-performance, flexible OPDs processed via large-scale, low-cost R2R printing technique.