Optimum Design Configuration of Thin‐Film Transistors and Quantum‐Dot Light‐Emitting Diodes for Active‐Matrix Displays

Abstract

AbstractActive matrix (AM) quantum‐dot light‐emitting diodes (QLEDs) driven by thin‐film transistors (TFTs) have attracted significant attention for use in next‐generation displays. Several challenges remain for the realisation of AM‐QLEDs, such as device design, fabrication process, and integration between QLEDs and TFTs, depending on their device structures and configurations. Herein, efficient and stable AM‐QLEDs are demonstrated using conventional and inverted structured QLEDs (C‐ and I‐QLEDs, respectively) combined with facile type‐convertible (p‐ and n‐type) single‐walled carbon nanotube (SWNT)‐based TFTs. Based on the four possible configurations of the QLED–TFT subpixel, the performance of the SWNT TFT‐driven QLEDs and the fabrication process to determine the ideal configuration are compared, taking advantage of each structure for AM‐QLEDs. The QLEDs and TFTs are also optimized to maximise the performance of the AM‐QLEDs—the inner shell composition of quantum dots and carrier type of TFTs—resulting in a maximum external quantum efficiency and operational lifetime (at an initial luminance of 100 cd m2) of 21.2% and 38 100 000 h for the C‐QLED, and 19.1% and 133100000 h for the I‐QLED, respectively. Finally, a 5×5 AM‐QLED display array controlled using SWNT TFTs is successfully demonstrated. This study is expected to contribute to the development of advanced AM‐QLED displays.