Study Of Anisotropic Polymer Heterojunction From The Self-assembly And Its Promising Polarization Photodetection

Heterojunctions are widely used in the active layers of various organic optoelectronic devices and play a vital role in charge separation and transmission.Due to the requirements of anisotropic optical and electronic characteristics,the research of heterojunction orientation engineering has received much attention in the field of optoelectronics,and has been used in light emitting transistor diodes,solar cells,memory devices,field effect transistors,and photodetectors.Unlike traditional polarized photodetectors,which require additional optical elements to achieve polarization detection,polarized photodetectors made from anisotropic heterojunction optical films can achieve polarization detection without additional optical elements,thus meeting the future miniaturized light detection systems.The advantages of miniaturization,flexibility,integration,and controllable detection wavelength have good application prospects in the field of polarized photodetectors.In this thesis,the preparation process of anisotropic heterojunction and its photoelectric properties of polarized photodetectors are studied in depth.In this work,an anisotropic heterojunction polymer film was prepared by a bottom-up self-assembly method for the first time,and was applied to a photodetector with its sensitivity to polarization detection and effect.Floating film transfer method is a simple one-step self-assembly method,which can make P-type and N-type polymers simultaneously form anisotropic heterojunction films.The correspondingly prepared photodetectors show significant photocurrent anisotropy and polarization detection capabilities,in which the relative photodetector sensitivity?D*?is 1.04×10¹² Jones?@660 nm,-1.2 V bias?.With a responsivity of 0.12 A/W,it can even be compared with conventional organic non-polarized photodetectors.The ratio of the photocurrents from the two orthotropic polarization directions is up to 6,which is better than most intrinsic polarization photodetectors.To reduce the dark current of the device,atomic force deposition technology is used to prepare the interface layer of the polarized photodetector.Based on the research of polarized light microscope image,ultraviolet absorption spectrum,atomic force microscope?AFM?and grazing incidence X-ray scattering image?GIXD?,the relationship between the optical performance and structure of the detector is discussed.This results indicate that the organic polarization photodetector prepared by one-step self-assembly method has great development potential in the emerging intrinsic organic polarization photodetector.