Effective Configuration of Hole Transport Layers for Solution-Processed Perovskite Light-Emitting Diodes

다국어 초록 (Multilingual Abstract)

Effective Configuration of Hole Transport Layer for Solution- Processed Quantum-Dot Light-Emitting Diodes Gwang-il Kim , Department of Chemistry The Graduate School Hanyang University Perovskite quantum-dots based light emitting diodes (PeLEDs) are promising for future the display industry due to their adjustable band gap, high photoluminescence quantum yield (PLQY) and high color purity. To improve the performance of PeLEDs, it is very important not only effective charge injection to EML but also match the charge balance of hole and electron. Here I report green perovskite quantum–dots based light emitting diodes with the employment of a triple hole transport layer (HTL) structure of (Poly[bis(4-phenyl)(2,4,6- trimethylphenyl)amine]) (PTAA)/ poly[(9,9-dioctylfluorenyl-2,7-diyl)-co- (4,40-(N-(p-butylphenyl))-diphenylamine)] (TFB)/PVK poly(9-vinylcarb azole) (PVK). Their highest occupied molecular orbital (HOMO) energy levels are - 5.2ev, -5.4ev, and -5.8ev, respectively. I estimated that, PTAA/TFB/PVK triple HTL provides an advantage for hole injection to EML. To Fabrication of PTAA/TFB/PVK triple HTL in solution process, must address the problem of solvent erosion. Therefore, I adopted the 1,4-dioxane as the solvent for PVK and the 1,2-dichloroethane as the solvent for TFB. After that, PeLEDs with PTAA single HTL, PTAA/TFB double HTL and PTAA/TFB/PVK triple HTL were fabricated. As a results, PeLEDs were exhibited that the device performance improved in the order of PTAA single HTL, PTAA/TFB double HTL and PTAA/TFB/PVK triple HTL. In addition, to match the charge balance with PTAA/TFB/PVK triple HTL, I adopted TPBi/PO-T2T double ETL. The final fabricated PeLEDs with PTAA/TFB/PVK triple HTL exhibited not only very low driving voltage of 2.22 V at 10 nits but also maximum current efficiency (CEmax), maximum power efficiency (PEmax), and maximum external quantum efficiency (EQEmax) of 35.76 cd A-1, 45.07 lm W-1, and 12.01%, respectively.

목차 (Table of Contents)

• List of Figures. iii
• List of Tables vi
• Abstract .vii
• Chapter 1. Introduction １
• 1.1. History of Perovskite １
• 1.2. Structure of Perovskite ２
• 1.3. Properties of Perovskite . ５
• 1.3.1. Advantage of Perovskite QDs . ５
• 1.3.2. Issues of Perovskite QDs ６
• 1.4. Perovskite Light-Emitting Diodes (PeLEDs) ９
• 1.4.1. Emission mechanism and structure of PeLEDs ９
• 1.4.2. Characteristics of PeLEDs １１
• 1.4.3. Strategies for improving performance of
• PeLEDs １２
• 1.5. Fabrication PeLEDs in Solution Process １４
• Chapter 2. Results and Discussion １７
• 2.1. Solvent Resistance １７
• 2.2. Investigation of the Stacking Status ２５
• 2.3. Investigation of Optoelectronic Characterization . ２９
• 2.4. Device Performance . ３２
• 2.4.1. Triple HTL with Single ETL of TPBi ３２
• 2.4.2. Triple HTL with Double ETL of TPBi/PO-T2T .. ４２
• Chapter 3. Conclusion ４８
• Chapter 4. Experimental Section . ４９
• 4.1. Materials ４９
• 4.2. Device Fabrication ４９
• 4.3. Characterization ５０
• References ５２
• 국문 요지 ５６