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Organic electroluminescent light emitting device and its associated performance based on the long-wave transmitter .

Author: QianJinCheng
Tutor: YuJunSheng
School: University of Electronic Science and Technology
Course: Optical Engineering
Keywords: The organic electroluminescent Polyvinylcarbazole Fluorene class of small molecules Long wave transmitters Exciplex
CLC: TN383.1
Type: Master's thesis
Year: 2010
Downloads: 64
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Abstract

Organic Light Emitting Diode (Organic light emitting diode OLED) With its high-brightness, high-efficiency, all-solid-state self-luminous, large viewing angle, thin, fast response, and can realize many advantages such as flexible displays, is very likely to become the LCD the mainstream of the next generation of displays and plasma display devices, at the same time, given that the world is facing energy crisis, the white OLED as a new type of energy-efficient lighting, caused widespread concern. The research and application of the organic electroluminescent device but there still exist many bottlenecks, for example, in the preparation of the OLED, often appear longer wavelength than the organic material of the intrinsic emission long-wave transmitter, seriously affecting the color purity of the device. Of organic electroluminescent light emitting device in the longwave transmitter has an important significance on the purity of the control and improve the color of the device for this problem, this thesis Expand the following work: (1) for the polyvinylcarbazole (PVK) electrically electroluminescent (EL) spectra often the phenomenon of long-wave transmitter, the systematic study of the impact of ultraviolet light irradiation of different solvents PVK photoluminescence (PL) spectrum, and inspected in the PL spectrum of UV irradiation on the PVK chloroform solution and the film, and absorption spectrum of the impact, and the EL spectrum characterization. The results showed that UV irradiation influence on PVK chloroform solution and film, along with a red shift of the PL spectra of irradiation time increases PVK (and more obvious solution redshift), its EL spectra in the red light area longwave emission enhanced. Moreover, the PVK emission layer, compared bcp TPBI as an electron transporting and hole blocking layer of the impact on the optical performance of the device, as well as the electrical properties, the results showed that the TPBi device of higher brightness, lower turn-on voltage, the device-based better performance. (2) Detailed analysis of the impact TPD doped EL spectra of PVK in the longwave transmitter PVK: TPD doped system for the luminescent layer, compared with BCP, TPBi as an electron transporting and hole blocking layer of the device performance. The structure of ITO / PVK: TPD (70 nm) / TPBi (10 nm) / Mg: Ag device performance and stable blue light and red emission. This bilayer devices based on the design of the structure of ITO / PVK: TPD (70 nm) / TPBi (10 nm) / Alq3 (20 nm) / Mg: Ag white device, by optimizing the PVK and TPD doping ratio , EL spectra adjustment device, when the PVK doped with TPD 1:4, the device in 11 V ~~ 15 V voltage range (0.33, 0.33) near the stability of white light emission. Meanwhile, the study of the influence of the doping ratio on the electrical properties of the white light devices, and found that with the increase in the proportion of TPD doped the brightness of the device, the current increases, the lower turn-on voltage, the performance of the device is more desirable. (3) In view of fluorene material often occurs the phenomenon of long-wave transmitter, small molecule materials BFLBBFLYQ fluorene as the core material, the first analysis BFLBBFLYQ: TPD doped system in the absorption spectrum and the PL spectra of the solution in the film state, characterized In doping system for the light-emitting layer of the EL spectra of the organic electroluminescent device, the systematic study of the long-wave transmitter the doped systems exciplex generated; discussed TPD of the influence of the incorporation of the device current and brightness. Prepared structure for the ITO / BFLBBFLYQ: TPD (50 nm) / Alq3 (40 nm) / Mg: Ag bilayer devices, in view of the doping system Alq3 emission spectrum coincide, a red fluorescent dye as a probe by its doped in the device in different locations, the inference the carrier recombination region of the bilayer devices located by Alq3 layer BFLBBFLYQ: TPD/Alq3 vicinity of the interface. Preparation Based the monolayer devices BFLBBFLYQ bilayer devices, the EL spectra of structures BFLBBFLYQ / BCP bilayer devices exist in a different from a single-layer device is located in an emission peak of 590 nm, which may is formed with BCP BFLBBFLYQ electrostrictive exciplex products, in addition, studies show that incorporated in BFLBBFLYQ PVK can eliminate this long-wave transmitter. To sum up, the work is based on carbazole and fluorene-based functional groups PVK and fluorene-based optical and electrical properties of the material depth and meticulous research laid the foundation for the production of high-performance, color stability Blu-ray and white light OLED devices.

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