n-Type polythiophene as a hole-blocking layer in inverted organic photodetectors
Jiahui Wang,
Sihui Deng,
Jun Ma,
Junli Hu,
Jun Liu
Affiliations
Jiahui Wang
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 PR China; School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026 PR China
Sihui Deng
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 PR China; School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026 PR China
Jun Ma
Key Laboratory of UV-Emitting Materials and Technology, Northeast Normal University, Ministry of Education, Changchun 130024 PR China
Junli Hu
Key Laboratory of UV-Emitting Materials and Technology, Northeast Normal University, Ministry of Education, Changchun 130024 PR China; Corresponding authors.
Jun Liu
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 PR China; School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026 PR China; Corresponding authors.
Organic photodetectors (OPDs) own unique advantages such as light weight, flexibility, low production cost, tunable detection wavelength, and thus are promising for a variety of applications. The lack of hole-blocking layer (HBL) materials impedes the reduction of dark current density and the enhancement of the performance of OPDs. Herein, we employed an n-type polythiophene n-PT1 as a HBL material for inverted OPDs. The specific solubility of n-PT1 in o-dichlorobenzene facilitates solution processing and enables multilayer device fabrication. The ultradeep-lying highest occupied molecular orbital energy level ensures a large hole injection barrier between cathode and active layer that suppresses dark current. As a result, compared to the control devices without n-PT1, the inverted OPD devices with n-PT1 as HBL demonstrate a two-order-of-magnitude reduction in dark current density and a one-order-of-magnitude increase in specific detectivity. To the best of our knowledge, this is the first solution processable HBL material for inverted OPDs.
