Using multi-hosts materials to improve the efficiency and life-time of organic light-emitting diode
| Autor: | Su, Hsiao-Tso, 蘇効佐 |
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| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 Used the blade coating process fabricated red and green organic light-emitting diodes in this study. I divided this study into two part; first part is how to improve device film and second part is change emitting layer structure. The device structure is Glass/ITO/HIL /HTL/EML/EIL/cathode. We formed the organic film by blade coating on the ITO substrate. There was the crystallizations on the organic film because of the unsmooth ITO substrate surface. The film surface defect will produce point discharge effecting device stability. For solving this problem, we increase hole injection layer (PEDOT:PSS) from 50 nm to 100 nm to cover unsmooth ITO substrate surface. Organic light-emitting diode emitting layer with multi-hosts materials system is different from Organic light-emitting diode emitting layer with co-hosts materials system commonly used in the previous paper. Used one host hole transport material and one host electron transport to balance charge in Organic light-emitting diode emitting layer with co-hosts materials system. If there is the big difference between host transport materials, one host transport material needs to dope large dose to balance charge in the emitting layer. When the organic material is doped above a certain dose, it will increase the chance of film surface crystallization. Because of this, we propose Organic light-emitting diode emitting layer with multi-hosts materials system. It can avoid organic materials crystallization by doping multi-hosts organic materials. The main study is changing the host transport material in the emitting layer of device based on simple structure in this study. Doping different hole host transport material combine hole host transport material (TCTA) and electron host transport material (SPPO13) in the emitting layer as an attempt. In these materials the best performance is 9-(4-tert-butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole (CzSi). The medium area device fabricated by CzSi whose current efficiency was 15.4 cd/A at an operating voltage of 8 V and lifetime is 90 hours at 500 cd/m2. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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