Study Of Organic Ultraviolet Photodetectors Based On NPB Donor

The technologies of ultraviolet photodetectors (UVPDs) have been widely appliedin national defense, astrophysical analysis, environmental pollution monitoring, firedetection, flame sensor, combustible gas analyzer, mineral exploration and mining,biological engineering, medical treatment and public health, as well as many otherfields. In military science, UVPDs are also widely applied, including missile warning,missile guidance, ultraviolet communication etc. It has a low false alarm rate, highanti-interference, good concealment, all-weather, good propagation characteristics etc.However, the characteristics of traditional inorganic UV detectors, such as thepreparation process complexity, high cost and difficulty of mass production, etc., limitits further development. Since the organic semiconductor materials havecharacteristics of a low price, simple preparation, a large area of thin film growth, etc.,Organic UV detectors cause widespread concern in the domestic and foreign scholars.Based on the above background, this thesis aims using the excellent electrondonor material NPB to explore its application in organic UV detection. UsingITO/quartz Glass as substrate, we select the BCP and C60two electron acceptormaterial to produce near-ultraviolet detectors.First, we prepared a “visible-blind” organic UV detector, whose structure wasGlass/ITO/NPB/BCP/Al. We briefly introduced device fabrication process, andoptimized the thickness of the donor NPB and the acceptor BCP. We tested thecharacteristics of the device, such as J-V characteristics, UV light responsecharacteristics. Finally, we got a UV-visible rejection ratio as high as509organic UVdetector.Second, in order to improve the UV light response of the device, we introduced anew organic acceptor material C60layer between NPB layer and BCP layer, whichhas a high electron mobility. We also tested the characteristic parameters of the deviceand optimized the thickness of the new active layer. Finally, under350nm UVirradiation, we got a photoresponsivity as high as315mA W-1organic UV detector at -5V bias.