Improvement Of Organic Optoelectronic Devices And Study Of Exciplex Emission

n recently years, organic optoelectronics have drawn more and more attention due to its potential beautiful prospect. Organic optoelectronics device are beginning to find technological application. The aim of this thesis is to investigate the physics process included and hence improve device performance. In this work, organic optoelectronic devices, including organic light-emitting diodes (OLEDs), photovoltaic (PV) devices, and UV photodetectors (PDs), are prepared. As the work mentioned above, I found the role of interface played is a very critical factor in performance of organic device. So I have taken in-depth research on the phenomenon showing on the interface in organic optoelectronic device.Due to the important application of near infrared (NIR) emission in memory, communication, military field and the compatibility difficulty between polymer fiber and inorganic luminescent materials, the development of oganic luminescent materials in NIR wavelength is becoming important. Chen and K. Leo has reported the NIR EL from heavy metal phthalocyanine, and the wavelength of emission is modulated by different heavy metal atom. But the emission intensity and efficiency is low. We selected copper phthalocyanine (CuPc) as NIR luminescent material and a red phosphor, bis(1-phenylisoquinolinato) iridium(III) acetylacetonate [Ir(piq)2acac] with high emission efficiency, as sensitizer. By codping the two phosphors into the same host material, CBP, the EL intensity peaked at 1120 nm of CuPc was enhanced by 15 times comparing with the CuPc monodoped device. The enhancement of NIR emission of CuPc emitter was principally attributed to an energy transfer from Ir(piq)2acac to CuPc. The phosphorescent life time of Ir(piq)2acac is shortend from 1.2μS in codoped system to 0.8μS in Ir(piq)2acac monodoped system, and the EL decreased from 10000cd/m2, 10.17cd/A in Ir(piq)2acac monodoped device to be hardly detected in codoped device. In according to the energy level, we think almost exciton formed in electrical exciting was transferred to CuPc phosphor by F?rster and Dexter process.The developing of OLED accelerate the developing other organic electronics filed, such as organic ultraviolet (UV) photodetector (PD) based on organic photovoltaic effect. The recent reports about UV-PD generally focus on single UV-A wave band, and the photo-current responses extend to visible area. By selecting 1,3,5-tris(3-methylphenyl-phenylamino)-triphenyamine (m-MTDATA) and 1,3,5-tris(N-phenylbenzimidazol-2-yl)-benzene (TPBi) as the electron donor and acceptor, respectively, an organic ultraviolet (UV) photovoltaic (PV) device was fabricated. Based on the work, we found that, for m-MTDATA, the maximum of absorption spectrum and photo current response spectrum locates at 350 nm and 370 nm, respectively. And, for TPBi, the maximum of absorption spectrum and photo current response spectrum locates at 315 nm and 330 nm, respectively. Consideration of the transparence of ITO glass is nearly zero befor 300 nm, and the film of Mg/Ag shows a high transparence at about 330 nm, we selected m-MTDATA as electron donor, TPBi as electron accepter, ITO as anode, Mg/Ag film as cathode, respectively, and fabricated a double wavelength sensitive UV-PD device. We selected the365 nm and 330 nm UV light as detecting source. The OPD device offers responses of 75.2 mA/W and 22.5 mA/W as the 365 nm and 330 nm UV light with intensities 1.0 mW/cm2 illuminate through anode and cathode, respectively.