High-performance inkjet-printed inverted QD-LEDs based on cross-linkable electron regulation layers

Abstract

In all-solution-processed quantum dot light-emitting diodes (QD-LEDs), zinc oxide nanoparticles (ZnO NPs) have been one of the most widely used electron transport layer materials. However, the high electron mobility and abundant surface defects of ZnO NPs usually entail not only charge imbalance in the QDs, but also exciton quenching at the QDs/ZnO interface. To overcome the shortcomings, a strategy is proposed by employing cross-linkable organics (isomeric TV-TmPY or TV-T2T) as an electron regulation layer (ERL) in inverted QD-LEDs. The spin-coated RGB QD-LEDs with TV-T2T inserts exhibit less sensitivity to interlayer thickness and great performance enhancements, with EQEs up to 20.2% for the red devices, 15.3% for the green devices, and 9.1% for the blue devices. The inkjet-printed RGB QD-LEDs with TV-T2T inserts also achieve EQEs of 18.4%, 13.3%, and 5.6%, respectively, representing the highest reported performance for inkjet-printed inverted QD-LEDs to date.