title: Improved Performance of Photomultiplication Polymer Photodetectors by Adjustment of P3HT Molecular Arrangement.
abstract: A series of photomultiplication (PM)-type polymer photodetectors (PPDs) were fabricated with polymer poly(3-hexylthiophene)-[6,6]-phenyl-C71-butyric acid methyl ester (P3HT-PC71BM) (100:1, w/w) as the active layers, the only difference being the self-assembly time of the active layers for adjusting the P3HT molecular arrangement. The grazing incidence X-ray diffraction (GIXRD) results exhibit that P3HT molecular arrangement can be adjusted between face-on and edge-on structures by controlling the self-assembly time. The champion EQE value of PPDs, based on the active layers without the self-assembly process, arrives at 6380% under 610 nm light illumination at -10 V bias, corresponding to the face-on molecular arrangement of P3HT in the active layers. The EQE values of PPDs were markedly decreased to 1600%, along with the self-assembly time up to 12 min, which should be attributed to the variation of absorption and hole transport ability of the active layers induced by the change of P3HT molecular arrangement. This finding provides an effective strategy for improving the performance of PM-type PPDs by adjusting the molecular arrangement, in addition to the enhanced trap-assisted charge-carrier tunneling injection.
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: 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: 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: Mile
authors.initials: M
authors.lastname: Gao
authors.affiliation: Key Laboratory of Luminescence and Optical Information, Ministry of Education, Beijing Jiaotong University , Beijing 100044, People's Republic of China.|Department of Materials Science and Engineering, University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Bin
authors.initials: B
authors.lastname: Hu
keywords: mobility; photomultiplication; polymer photodetectors; self-assembly; tunneling injection