Dark Current Reduction Strategy via a Layer-By-Layer Solution Process for a High-Performance All-Polymer Photodetector

• Published in: ACS applied materials & interfaces Vol. 11; no. 8; pp. 8350 - 8356
• Main Authors: Zhong, Zhiming, Bu, Laju, Zhu, Peng, Xiao, Tong, Fan, Baobing, Ying, Lei, Lu, Guanghao, Yu, Gang, Huang, Fei, Cao, Yong
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 27.02.2019
• Subjects: electrical conductivity; equipment performance; polymers; wavelengths; layer-by-layer process; imide functionalized benzotriazole; gradient bulk heterojunction; noise spectral density; all-polymer photodetector
• ISSN: 1944-8244; 1944-8252; 1944-8252
• DOI: 10.1021/acsami.8b20981

The ideal bulk-heterojunction for high-performance organic photodetectors prefers a morphology with a vertically gradient component to suppress the leaking current. Here, we demonstrate an all-polymer photodetector with a segregated bulk-heterojunction active layer. This all-polymer photodetector exhibits a dramatically reduced dark current density because of its built-in charge blocking layer, with a responsivity of 0.25 A W–1 at a wavelength of approximately 600 nm and specific detectivity of 5.68 × 1012 cm Hz1/2 W–1 as calculated from the noise spectra at 1 kHz. To our knowledge, this is among the best performances reported for photodetectors based on both polymeric donor and acceptor in the photoactive layer. These findings present a facile approach to improving the specific detectivity of polymer photodetectors via a layer-by-layer solution process.