论文标题
全面取向的胶体量子井的高方向，高效的解决方案加工发光二极管
Highly-directional, highly-efficient solution-processed light-emitting diodes of all-face-down oriented colloidal quantum wells
论文作者
论文摘要
半导体胶体量子井（CQWS）由于其独特的特性，包括其高度各向异性的光学转变偶极偶极力矩（TDM），因此使纳米晶体的纳米晶体具有令人兴奋的准2D类纳米晶体。因此，在电致发光设备中，采用面向下向取向的CQW膜作为发射层（EML），预计将大大提高光子超过耦合效率。在这里，我们使用单个全面向底面的自我组装单层（SAM）CQWS的单个全面处理的胶体量子发光二极管（CQW-LEDS），可实现高水平的内置（IP）TDMS的高水平。该SAM膜将远程偶联的效率从22％（标准的随机发射器中的22％）提高到34％（面向下方的发射器）和电荷注入效率。这种由SAM-CQW领导的体系结构使溶液处理类型的CQW LED类型的高水平的外部量子效率为18.1％，使其效率的性能与基于混合有机无机蒸发的CQW-LED和所有其他最佳解决方案处理的LED相同。此外，该体系结构提供的高最大亮度为19,800 cd/m2，在100 cd/m2时长247小时，以及饱和的深红发射（651 nm）。这些发现表明，CQWS定向自组装的有效性是电动驱动的发射层在改善CQW领导的算法和外部量子效率方面的有效性。
Semiconductor colloidal quantum wells (CQWs) make an exciting quasi-2D class of nanocrystals thanks to their unique properties including their highly anisotropic optical transition dipole moment (TDM). Thus, employing a film of CQWs with face-down orientation as an emissive layer (EML) in an electroluminescent device is expected to substantially boost photon outcoupling efficiency. Here, we show all-solution-processed colloidal quantum well light-emitting diodes (CQW-LEDs) using a single all-face-down oriented self-assembled monolayer (SAM) film of CQWs that enables a high level of in-plane (IP) TDMs of 92%. This SAM film significantly enhances the outcoupling efficiency from 22% (of standard randomly-oriented emitters) to 34% (of face-down oriented emitters) and charge injection efficiency. This SAM-CQW-LED architecture enables a record high level of external quantum efficiency of 18.1% for the solution-processed type of CQW-LEDs, putting their efficiency performance on par with the hybrid organic-inorganic evaporation-based CQW-LEDs and all other best solution-processed LEDs. In addition, this architecture provides a high maximum brightness of 19,800 cd/m2 with a long operational lifetime of 247 h at 100 cd/m2 along with saturated deep-red emission (651 nm). These findings indicate the effectiveness of oriented self-assembly of CQWs as electrically-driven emissive layers in improving outcoupling and external quantum efficiencies in the CQW-LEDs.
