中国物理B ›› 2019, Vol. 28 ›› Issue (3): 38501-038501.doi: 10.1088/1674-1056/28/3/038501
• INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY • 上一篇 下一篇
Wei Gong(龚伟), Tao An(安涛), Xinying Liu(刘欣颖), Gang Lu(卢刚)
Wei Gong(龚伟), Tao An(安涛), Xinying Liu(刘欣颖), Gang Lu(卢刚)
摘要:
Photomultiplication (PM) structure has been widely employed to improve the optoelectronic performance of organic photodetectors (OPDs). However, most PM-type OPDs require a high negative operating voltage or complex fabrication. For obtaining high-efficiency OPDs with low voltage and easy process, here the bulk heterojunction (BHJ) structure of high exciton dissociation efficiency combined with the method of trap-assisted PM are applied to the OPDs. In this paper, we investigate the operating mechanism of OPDs based on poly(3-hexylthiophene) (P3HT):(phenyl-C61-butyric-acid-methyl-ester) (PC61BM), and poly-{[4,8-bis[(2-ethylhexyl)oxy]-benzo[1,2-b:4,5-b]dithiophene-2,6-diyl]-alt-[3-fluore-2-(octyloxy)carbonyl-thieno[3,4-b]thiophene-4,6-diyl]} (PBDT-TT-F):PC61BM doped with C60 as active layer. Furthermore, the influence of C60 concentration on the optoelectronic performances is also discussed. With 1.6 wt.% C60 added, the P3HT:PC61BM:C60 OPD exhibits a 327.5% external quantum efficiency, a 1.21 A·W-1 responsivity, and a 4.22×1012 Jones normalized detectivity at -1 V under 460 nm (0.21 mW·cm-2) illumination. The experimental results show that the effective electron traps can be formed by doping a small weight of C60 into BHJ active layer. Thus the PM-type OPDs can be realized, which benefits from the cathode hole tunneling injection assisted by the trapped electrons in C60 near the Al side. The efficiency of PM is related to the C60 concentration. The present study provides theoretical basis and method for the design of highly sensitive OPDs with low operating voltage and facile fabrication.
中图分类号: (Photodetectors (including infrared and CCD detectors))