Zhang Heng, Wang Jiming, Chen Shuming
Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, P. R. China.
School of Resources, Environment and Materials, Guangxi University, Nanning, 530004, P. R. China.
Adv Mater. 2024 Apr;36(16):e2312334. doi: 10.1002/adma.202312334. Epub 2024 Jan 23.
Alternating current (AC)-driven quantum-dot light-emitting diodes (QLEDs) are superior to direct current-driven QLEDs because they can be directly integrated into household AC electricity and have high stability. However, achieving high-performance AC-driven QLEDs remains challenging. In this work, a bipolar QLED with coplanar electrodes is realized by horizontally connecting a regular QLED and an inverted QLED in series using an Al bridging layer. The bipolar QLED can be turned on with either a positive or a negative bias voltage, with a high external quantum efficiency (EQE) of 22.9%. By replacing the Al with Ag, the resistances of the electron transport layers are effectively reduced, and thus the bipolar QLED shows an enhanced brightness of 16370 cd m at 15 V. By connecting multiple bipolar QLEDs in series, the resulting light source can be directly driven by a 220 V/50 Hz household power supply without the need for back-end electronics. The bipolar QLED can also be realized by vertically stacking a regular QLED and an inverted QLED with a metallic intermediate connection layer. It is demonstrated that the coplanar or vertical bipolar QLEDs could find potential applications in household AC electricity play-and-plug solid-state lighting and single- or double-sided displays.
交流（AC）驱动的量子点发光二极管（QLED）优于直流驱动的QLED，因为它们可以直接集成到家用交流电中且具有高稳定性。然而，实现高性能的交流驱动QLED仍然具有挑战性。在这项工作中，通过使用Al桥接层将常规QLED和倒置QLED水平串联连接，实现了具有共面电极的双极QLED。该双极QLED可以用正偏压或负偏压开启，具有22.9%的高外量子效率（EQE）。通过用Ag替代Al，有效地降低了电子传输层的电阻，因此该双极QLED在15 V时显示出增强的亮度，为16370 cd m。通过将多个双极QLED串联连接，所得光源可以由220 V/50 Hz的家用电源直接驱动，而无需后端电子设备。双极QLED也可以通过用金属中间连接层垂直堆叠常规QLED和倒置QLED来实现。结果表明，共面或垂直双极QLED在家用交流即插即用固态照明以及单面或双面显示器中具有潜在应用。
