Davidson-Hall Tyler, Aziz Hany
Department of Electrical and Computer Engineering and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
ACS Appl Mater Interfaces. 2020 Apr 8;12(14):16782-16791. doi: 10.1021/acsami.9b23567. Epub 2020 Mar 26.
This work investigates the effect of the hole transport layer (HTL) on the stability of electroluminescent quantum dot light-emitting devices (QDLEDs). The electroluminescence half-life (LT50) of QDLEDs can be improved by 25× through the utilization of a cascading HTL (CHTL) structure with consecutive steps in the highest occupied molecular orbital energy level. Using this approach, a LT50 of 864,000 h (for an initial luminance of 100 cd m) is obtained for red QDLEDs using a conventional core/shell QD emitter. The CHTL primarily improves QDLED stability by shifting excessive hole accumulation away from the QD/HTL interface and toward the interlayer HTL/HTL interfaces. The wider electron-hole recombination zone in the CHTL for electrons that have leaked from the QD layer results in less HTL degradation at the QD/HTL interface. This work highlights the significant influence of the HTL on QDLED stability and represents the longest LT50 for a QDLED based on the conventional core/shell QD structure.
本工作研究了空穴传输层（HTL）对电致发光量子点发光器件（QDLED）稳定性的影响。通过利用最高占据分子轨道能级具有连续台阶的级联空穴传输层（CHTL）结构，QDLED的电致发光半衰期（LT50）可提高25倍。采用这种方法，使用传统核壳量子点发射体的红色QDLED在初始亮度为100 cd/m²时获得了864,000小时的LT50。CHTL主要通过将过多的空穴积累从量子点/HTL界面转移到层间HTL/HTL界面来提高QDLED的稳定性。对于从量子点层泄漏的电子，CHTL中更宽的电子 - 空穴复合区导致量子点/HTL界面处的HTL降解更少。这项工作突出了HTL对QDLED稳定性的重大影响，并且代表了基于传统核壳量子点结构的QDLED最长的LT50。
