Optical and Electrical Analysis of Annealing Temperature of High-Molecular Weight Hole Transport Layer for Quantum-dot Light-emitting Diodes

• Published in: Scientific reports 2019-07, Vol.9 (1), p.10385-9, Article 10385
• Main Authors: Han, Young Joon, An, Kunsik, Kang, Kyung Tae, Ju, Byeong-Kwon, Cho, Kwan Hyun
• Format: Article
• Language: English
• Subjects: 639/166/987; 639/301/1005/1007; Annealing; Capacitance; Fourier transforms; Hardness; Humanities and Social Sciences; Light emitting diodes; Molecular weight; multidisciplinary; Science; Science (multidisciplinary); Voltage
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-019-46858-6

In this study, we introduce optimization of the annealing conditions for improvement of hardness and hole transporting properties of high-molecular weight poly [9, 9-dioctylfluorene-co-N-(4-(3-methylpropyl)) diphenylamine] (TFB) film used as a Hole Transport Layer (HTL) of Quantum-dot Light-emitting Diodes (QLEDs). As annealing temperatures were increased from 120 °C to 150 °C or more, no dissolving or intermixing phenomena at the interface between HTL and Quantum-Dot Emission Layer (QDs EML) was observed. However, when the annealing temperatures was increased from 150 °C to 210 °C, the intensity of the absorbance peaks as determined by Fourier Transform Infrared (FT-IR) measurement was found to relatively decrease, and hole transporting properties were found to decrease in the measurement of current density - voltage (CD - V) and capacitance - voltage (C - V) characteristics of Hole Only Devices (HODs) due to thermal damage. At the annealing temperature of 150 °C, the QLEDs device was optimized with TFB films having good hardness and best hole transporting properties for solution processed QLEDs.