title: Trap-assisted photomultiplication polymer photodetectors obtaining an external quantum efficiency of 37,500%.
abstract: A smart strategy is reported to obtain photomultiplication (PM) type polymer photodetectors (PPDs) based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) which are commonly used in polymer solar cells. The PPDs with 1 wt % PC61BM exhibit a champion EQE of 37,500% under 625 nm illumination with an intensity of 8.87 μW cm(-2) at -19 V bias. The PM phenomenon of PPDs with rather low PC61BM doping ratios should be attributed to the enhanced hole tunneling injection assisted by trapped electrons in PC61BM near the Al cathode, which can be completely demonstrated from (i) turning distribution of electron traps by changing P3HT:PC61BM doping weight ratios from 200:1 to 1:1; (ii) adjusting interfacial barrier width by inserting LiF layer between the active layer and the Al cathode.
authors.affiliation: †Key Laboratory of Luminescence and Optical Information, Ministry of Education, Beijing Jiaotong University, Beijing 100044, People's Republic of China.
authors.forename: Lingliang
authors.initials: L
authors.lastname: Li
authors.affiliation: †Key Laboratory of Luminescence and Optical Information, Ministry of Education, Beijing Jiaotong University, Beijing 100044, People's Republic of China.
authors.forename: Fujun
authors.initials: F
authors.lastname: Zhang
authors.affiliation: †Key Laboratory of Luminescence and Optical Information, Ministry of Education, Beijing Jiaotong University, Beijing 100044, People's Republic of China.
authors.forename: Wenbin
authors.initials: W
authors.lastname: Wang
authors.affiliation: †Key Laboratory of Luminescence and Optical Information, Ministry of Education, Beijing Jiaotong University, Beijing 100044, People's Republic of China.
authors.forename: Qiaoshi
authors.initials: Q
authors.lastname: An
authors.affiliation: †Key Laboratory of Luminescence and Optical Information, Ministry of Education, Beijing Jiaotong University, Beijing 100044, People's Republic of China.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.affiliation: †Key Laboratory of Luminescence and Optical Information, Ministry of Education, Beijing Jiaotong University, Beijing 100044, People's Republic of China.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Sun
authors.affiliation: †Key Laboratory of Luminescence and Optical Information, Ministry of Education, Beijing Jiaotong University, Beijing 100044, People's Republic of China.
authors.forename: Miao
authors.initials: M
authors.lastname: Zhang
keywords: band bending; organic photodetector; photomultiplication; trap; tunneling injection