P‐9.6: High Efficiency Deep‐Red Colloidal Quantum Well Light‐Emitting Diodes Enabled by Balanced Carrier Injection

Colloidal quantum wells (CQWs) are regarded as a frontier class of light‐emitting diodes (LEDs) owing to their efficient and ultranarrow luminescence spectrum, directional emission, and high light extraction. However, CQW‐LEDs with deep‐red (> 660 nm) light emission, a vital part for high‐definition color displays, optical medical, and horticultural lighting, remain a great challenge. Herein, high‐efficiency deep‐red CQW‐LEDs are reported. With the enhancement of device engineering, the LED devices that based new CQW materials have shown high external quantum efficiency of 9.89%. Additionally, Mg‐doped zinc oxide (ZnMgO) and In2O3 as electron transport layer (ETL) are introduced into CQW‐LEDs for the first time, and the effect of different ETLs on carrier injection balance of CQW‐LEDs is investigated. Furthermore, the first prototype active‐matrix CQW‐LED (AMCQW‐LED) pixel circuit was constructed by connecting thin film transistor (TFT) source terminal with CQW‐LED. The findings may not only begin the first step that TFT drives CQW‐LED, but also reveal the carrier injection balance mechanism of CQW‐LEDs, and can be further applied to other wavelengths of CQW‐LEDs.