Research On Performance Improvement Of Organic Photodetectors By Interface Control

Organic photodetector as one of important optoelectronic devices,by its excellent mechanical flexibility,low production costs,wide selection of materials and other advantages has attracted a lot of research scholars attention and research,which studied more are the the charge transfer characteristics of the OPD,the interface control of the device performance improvement.In order to improve the performance of OPD,it is necessary to ensure that carriers have low energy barrier in the transmission,in addition to the high absorption rate and high carrier mobility of the acceptor material.When the interface of the donor and acceptor appears to bandbending,forming the interface dipole,the energy barrier between the organic materials also have a great impact.OPD devices concerned about the dark current,light and dark current ratio and other parameters,the dark current is the less the better,light and dark current ratio is the more the better.In order to reduce the dark current of the OPD device,the resistivity of the film in the device can be improved by doping,thereby reducing the dark current of the device and improving the device's dark current ratio.The main contents of this paper include two parts,as follows:The first part studies the performance of doping-controlled ZnO nanorods/PVK interface to improve the UV photodetector.The AZO thin films with different concentrations of Al were characterized by XRD and PL,the result show that the increase of Al concentration makes the crystallization qualityof the films worse,and the resistance of the films increases.And then prepared the organic and inorganic composite ZnO/PVK-based UV detector,the ZnO/PVK nanoparticles were prepared by sol-gel method,the ZnO/PVK nanorod arrays were prepared by hydrothermal method.AZO thin films with different Al concentrations were applied to PVK/ZnO-based UV detectors to reduce the dark current of the devices,thereby improving the device's optical and dark current ratio and improving the performance of the devices.By measuring the absorption spectrum of the device,JV curve,EQE spectra were used to improve the performance of the device.When the Al concentration is 10at%,the dark current ratip of the ZnO/PVK-based UV detector reaches the order of 103,the dark current density of the device reached 17.2uA/cm2,the response reached 9.25A/W under a bias voltage of-5V and 365 nm,2mW/cm2 of ultraviolet light.In the second part,the influence of multilayer DCJTB/C60 interface on the performance of organic near infrared detectord is studied.The device is prepared by vacuum deposition method.By changing the number of layers of DCJTB/C60,the performance of the detector is optimized.The device has good performance when it has3 layers of DCJTB/C60 film.The photocurrent density of the device reached 0.18A/cm2 under 980nm near-infrared laser irradiation at-1V bias.Using the method of UPS and XPS,it is found that the interface of the DCJTB/C60 interface has a band bending,and the interface dipole is formed.The working mechanism of the multilayer DCJTB/C60 organic near infrared detector is studied.