| High performance ultraviolet (UV) photodetector is receiving increasingly attention due to its significant applications in fire warning, environmental monitoring, scientific research, astronomical observation etc. The enhancement in performance of UV photodetecor has been impeded by lacking of a high-efficiency heterojunction in which UV photons can efficiently convert into charges. UV photodetector is a kind of important optoelectronic devices that has vital applications in both scientific and engineering fields. The development of UV photodetectors has been impeded because of lacking stable p-type wide-gap semiconductor which is crucial for high-performance, low-cost, large-array UV photovoltaic detector.In this thesis, we have mainly work includes two contents; (1) In this thesis we report a novel UV photovoltaic detector fabricated using 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) as a sole photoactive material, and observed the obvious photovoltaic properties through the systematic study for the microtopography and photoelectric property of this material. Of course, the other characterization technology were carried out, such as photoluminescence excitation spectra(PLE), photoluminescence(PL), Spectroscopic ellipsometry(SE), Transient response spectrum, J-V, C-V property and UV-visible absorbance have been systematically investigated to disclose the internal mechanism. It is obvious that under UV (365 nm LED) illumination (0.50 mW/cm~2) the device shows a dramatic increase (2-3 order of magnitudes) in current density, indicating our device is highly UV sensitive, However, the photoelectric response time of the device is less than 200 ms. At the seam time highest detectivity is gotten at-IV, the value is 9.02×1011 cmHz1/2W-1, compare with the traditional UV photodetectors such as the GaN, SiC, and high photoresponse of 19 mA/W at 2 V bias. The present study paves the way for developing high-performance, low-cost UV focal plane array (FPA) detectors.(2) The planar heterojunction hybrid ultraviolet photodetector adjusted solution spin coating method were fabricated with donor as PVK and acceptor as ZnO nanoplatelets fabricated with wet chemistry method. The device used the PVK and ZnO hybrid thin films as active layer. Under the LED with wavelength at 365 nm for power density with 1.30 mW/cm~2 illumination the device show those performance the current density is 144 mA/cm~2, the corresponding photoresponsivity get 4.66×103 A/W and a ratio of the current under illumination to the dark current is as high as-103 under the bias voltage at 2 V. In order to enhance the performance of the device, we put forward an effective solution, which is the ITO/Glass was replaced with PEDOT:PSS(1000)/quartz and the PVK and ZnO compound thin films used as active layer. This improved device was observed the photoresponsivity is 7.27×103 A/W, which is enhanced 49% compared with the planar heterojunction hybrid ultraviolet photodetector, the (D*) reach 9.02×1011 cmHz1/2W-1 which is enhanced 1 order of magnitude compared with previous device and the device shows a dramatic increase 3 order of magnitudes in current density, indicating our device is highly UV sensitive the same condition. These results indicate the properties of the device were improved by optimized methods.The research results show that the organic semiconductor material is expect ed to, the application of the photoelectric detection research field, continues to deepen the theoretical analysis and understanding of organic semiconductor mate rials and Study on selection of materials and devices for the further expansion of the organic semiconductor purple outside detecting and processing of soluble liquid organic semiconductor purple extension and detection application of mater ials and devices provide a solid foundation. |
PDF Full Text Request