Dipole Modulation\nEngineering Enhances Structural\nOrder of PEDOT:PSS for Efficient and Stable InP-Based QLEDs

Indium phosphide (InP)-based quantum dot light-emitting\ndiodes\n(QLEDs) are promising for future lighting and display applications\ndue to their high color purity and brightness. However, their efficiency\nand stability are often limited by the disordered structure of the\nwidely used poly(3,4-ethylenedioxythiophene):polystyrenesulfonate\n(PEDOT:PSS), which impairs charge transport. Herein, we present a\nstrategy to enhance the performance of InP-based QLEDs by modifying\nPEDOT:PSS through interfacial dipole modulation using molybdenum oxide\n(MoO<sub><i>x</i></sub>) nanoparticles. The strong hydrogen\nbonding between MoO<sub><i>x</i></sub> and PSS creates strong\ndipole–dipole interactions, reducing the separation of PEDOT-rich\nregions, enhancing π–π stacking and conductivity.\nThis optimization facilitates balanced electron and hole injection,\nincreasing external quantum efficiency (EQE) from 12.2% in control\ndevices to 17.8% in the treated devices, along with a brightness enhancement\nfrom 32,998 to 43,567 cd m<sup>–2</sup>. Notably, our treated\ndevices exhibit a reduction in efficiency attenuation compared to\nother reported InP-based QLEDs, particularly at high brightness levels\nof 5000 and 10,000 cd m<sup>–2</sup>, with EQE attenuation\nof only 4 and 9%, respectively, compared to 16 and 30% for controls.\nThis work highlights the potential of dipole engineering in advancing\nInP-based QLED technology, providing a pathway for developing high-performance,\nstable, and eco-friendly lighting and displays.