Organic light emitting device

A technology of organic light-emitting device and light-emitting layer, applied in the field of OLED, can solve problems such as difficulty in hole injection

Active Publication Date: 2007-12-12
SAMSUNG DISPLAY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Conventionally, it is well known in the art that when a layer having a large work function, ionization energy or HOMO absolute value of HIL is formed on ITO, the work function is 4.7-4.9 eV, and thus there is a high energy between ITO and HIL barrier, and thus hole injection becomes difficult

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation Embodiment 1

[0208] Preparation Example 1: Polyaniline (PANI) Conductive Polymer Composition

[0209] Polystyrenesulfonic acid-graft-polyaniline (PSSA-g-PANI) was polymerized as a self-doping conductive material using the known synthetic method of [W.J.Bae et al., Chem. Comm., pp2768-2769, 2003]. In this embodiment, the weight ratio of PSSA polymer chains and grafted PANI chains is 1:0.15. The number average molecular weight of PSSA-g-PANI was 35,000. This material was melted in water to 1.0% by weight. Then, a perfluorinated ionomer (PFI) was purchased from Aldrich Co., dispersed to 5 wt% in a solvent with a water to alcohol volume ratio of 0.45:0.55, and isopropanol and 5 wt% PFI at 1.0 wt% The PSSA-g-PANI solution was mixed and used as the material to form HIL 11. This sample is referred to as Sample A.

[0210] [Formula 14]

[0211]

[0212] (where x=1300, y=200, x=1)

preparation Embodiment 2

[0213] Preparation Example 2: Preparation of PEDOT-PSS / PFI Conductive Polymer Composition

[0214] PEDOT-PSS (model: Baytron P VP A14083) from H.C. Starck, a subsidiary of Bayer Aktien AG, was purified to control the Na and sulfate content to 5 ppm or less. Then, PFI of formula 14 was purchased from Aldrich Co. dispersed to 5 wt% in water and alcohol. Then, HIL 11 with each different composition of PEDOT-PSS was prepared. The proportions of this composition are listed in Table 1 below.

[0215] [Table 1]

[0216] sample code

Embodiment 1

[0217] Evaluation Example 1 - Work Function Evaluation of Conductive Polymer Films

[0218] The conductive polymer compositions obtained in Preparation Examples 1 and 2 were spin-coated on an ITO substrate to form a thin layer to a thickness of 50 nm, and heated on a hot plate in air at 200° C. for 5 minutes, and the conductive polymer was evaluated The work function of the composition. Surface Analyzer Model AC2 as a photoelectron spectrometer in air (PESA) manufactured by RIKEN KEIKI, Co., Ltd. was used as an evaluation apparatus. Sample A shows a work function of 5.6 eV, sample B shows a work function of 5.55 eV, sample C shows a work function of 5.63 eV, sample D shows a work function of 5.72 eV, and sample E shows a work function of 5.79 eV, and sample F showed a work function of 5.95 eV.

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Abstract

Provided are an organic light emitting device (OLED) comprising: a first electrode; a second electrode; a hole injection layer (HIL), a hole transporting layer (HTL), and an emitting layer sequentially formed between the first electrode and the second electrode, wherein the work function, the IP or the absolute value of the highest occupied molecular orbital (HOMO) level of the HIL is greater than or equal to the absolute value of HOMO level of the HTL. In the OLED, the energy relationships between organic layers are controlled to facilitate hole injection and optimize the charge balance. Thus the efficiency of the OLED improves and the lifetime of the OLED increases.

Description

technical field [0001] The present invention relates to an organic light emitting device (OLED), and more particularly, to an OLED in which the energy relationship of the layers forming the OLED is controlled to facilitate hole injection and optimize charge balance for improved efficiency and OLEDs with increased lifespan. Background technique [0002] The organic light-emitting device is a self-emission display device utilizing the principle that when a current is applied to a thin layer of a fluorescent or phosphorescent organic compound (hereinafter referred to as an "organic layer"), electrons and holes are combined in the organic layer, thereby emitting light . Organic light-emitting devices can be made lightweight, easy to fabricate due to their simple components, and can provide wide viewing angles and high-quality images. Also, the light emitting device can realize perfect moving images and high color purity, and can operate at low power and low voltage, and thus i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L51/50H01L51/54H05B33/12
CPCH01L51/0037H01L51/0059H01L51/0081H01L51/5048H01L51/5088H10K85/1135H10K85/631H10K85/324H10K50/14H10K50/17C09K11/06H05B33/22H05B33/14
Inventor 李泰雨朴钟辰金茂显蒋胜旭
Owner SAMSUNG DISPLAY CO LTD
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