Enhancing device characteristics of InP quantum dot LED through structural modification with polyethylene glycol blend

Abstract

This study explored the integration of polyethylene glycol (PEG) into InP-based quantum dot (QD) light-emitting diodes (LEDs). By 5 wt% of PEG 400 blended into the QD emission layer (EML), we achieved an enhancement in both current efficiency (100 %) and external quantum efficiency (91 %). X-ray reflectivity revealed significant morphological changes in the QD EML upon PEG incorporation, primarily manifesting as increased thickness in the dense surface region without affecting the total thickness. This adjustment influenced electron density distribution, impacting hole and electron flow. Overall, the addition of PEG not only improved the electrical properties of QD LEDs but also reshaped the internal morphology of the QD EML. Notably, the efficiency improvements observed rival those achieved by integrating traditional hole transport materials into QD EMLs.