정공 전달층용 고분자 합성과 백색 OLED 소자의 특성평가 = Effect of polymer HTL and Device Structure on the Properties of White OLED

다국어 초록 (Multilingual Abstract)

White light emitting OLED(organic light emitting diode)s were fabricated utilizing DPVBi as blue host material and rubrene as orange light emitting dopant with different structures. Of the 4 different structure OLED devices the one configuration was found to give high luminescence(12,360 cd/㎡), efficiency(2.7 cd/A) and white color coordinates(X=0.33, Y=0.32).
The copolymer containing carbazole and aromatic amine unit were also synthesized by using Pd-catalyzed polycondensation reaction. The polymers were characterized and their UV and PL properties were examined in solution and film state .
The two polymer samples, poly [N-(2ethylhexyl)-3,6-carbazole-alt-aniline] [P1] and poly[(bis(6-N-(2-ethylhexyl)-carbazole-3-yl))-alt-aniline] [P2],
were tested both as light emitting layer and hole injection/transparent layer in the OLED devices.
The polymers P1 and P2 were then tried as hole injection/transport layer in the OLED devices since the polymers contained aromatic amine moiety in the repeating unit. The OLED devices fabricated had structure of (ITO/PEDOT : PSS/conjugatedpolymer/DPVBI(rubrene 0.2 %)/DPVBi/BCP/Alq3/Al) and (ITO/conjugatedpolymer
/DPVBi(rubrene 0.2 %) /DPVBi/BCP/Alq3/Al). Here PEDOT:PSS is a commercially available polymer currently used as hole injection material. The former OLED device had PEDOT:PSS as hole injection layer and synthesized polymer as hole transport layer and the latter OLED device had synthesized polymer both as hole injection and transport layer.
The performance of white OLED devices with polymer P1, P2 as HIL/HTL layer contained blue host(DPVBi) and orange dopant(rubrene) as emitting layer. The OLED device with polymer(P1) as HIL/HTL layer exhibited white color coordinate at (X=0.32, Y=0.31), luminescence 347 cd/㎡ at 19V and efficiency 0.10 cd/A. The OLED device with polymer(2) as HIL/HTL layer showed white color coordinate at (X=0.33, Y=0.29), luminescence 470 cd/㎡ at 20V and efficiency 0.30 cd/A.
It was noted that the new polymer synthesized showed the potential as new hole injection/transport layer material which could replace the known PEDOT:PSS hole injection layer material.

목차 (Table of Contents)

• I. 서 론 1
• 1-1. OLED 소자 재료 및 기술 1
• 1-2. 백색 OLED 소자 및 재료 5
• II. 실 험 9
• 1. 시약 및 재료 9
• 2. 정공 전달층용 고분자의 합성 11
• 2-1. Poly[N-(2-ethylhexyl)-3,6-carbazole-alt-aniline] (P1)의 합성 11
• 2-2. Poly[(bis(6-N-(2-ethylhexyl)-carbazole-3-yl))-alt-aniline] (P2)의 합성 13
• 3. 백색 OLED 소자의 제작 16
• 3-1. ITO 유리 전처리 공정 16
• 3-2. 백색 OLED 소자의 제작 18
• 3-2-1. 백색 OLED의 구조 및 사용한 재료 18
• 3-2-2. 정공 주입층의 형성 22
• 3-2-3. 정공 전달층의 형성 22
• 3-2-4. 발광층의 형성 23
• 3-2-5. 전자 주입층과 음극 전극의 형성 23
• 4. 측정기기 및 분석 24
• III. 결과 및 고찰 26
• 1. 정공 전달층용 고분자의 합성 확인 및 특성 분석 26
• 1-1. Poly[N-(2-ethylhexyl)-3,6-carbazole-alt-aniline](P1)의 특성 26
• 1-2. Poly[(bis(6-N-(2-ethylhexyl)-carbazole-3-yl))-alt-aniline](P2)의 특성 30
• 2. OLED용 재료들의 전기 광학적 특성 평가 36
• 3. 백색 OLED 소자 제작 및 특성 평가 40
• 3-1. DPVBi/Rubrene 발광 재료를 이용한 백색 OLED 소자 제작 및 특성 40
• 3-2. 3 파장 방식 백색 OLED 소자 제작 및 특성 46
• 3-3. 블록킹 층을 이용한 백색 OLED 소자 제작 및 특성 49
• 3-4. 2 파장 방식 백색 OLED 소자의 제작 및 특성 52
• 3-5. 고분자를 사용한 정공 전달층의 백색 OLED 소자 제작 및 특성 55
• 3-5-1. 고분자 정공 전달층의 형성 조건 및 표면특성 55
• 3-5-2. P1 고분자를 정공 전달층으로 사용한 백색 OLED 59
• 3-5-3. P2 고분자를 정공 전달층으로 사용한 백색 OLED 66
• IV. 결 론 69
• 참 고 문 헌 71