Localized surface plasmon-enhanced blue electroluminescent device based on ZnSeTe quantum dots and AuAg nanoparticles

Abstract

Plasmonic quantum dot-based light-emitting diodes (QLEDs) exploit the localized surface plasmon resonance (LSPR) effect of metal nanoparticles (NPs) for enhancement of electroluminescent (EL) performance. To date, several plasmonic EL devices exclusively based on environment-malign (i.e., Cd- and Pb-containing) quantum dots (QDs) with a special focus on green emissivity have been fabricated by commonly employing Au NPs possessing the characteristic absorption peak in the green region. Meanwhile, the fabrication of other colored plasmonic devices, particularly consisting of Cd-free QDs along with other metal NPs, still remains unexplored. Herein, we demonstrate the first case of LSPR-enhanced Cd-free blue QLEDs integrated with ZnSeTe QDs and AuAg alloy NPs. In the present QLED fabrication, AuAg NPs, whose absorption features are spectrally matched with the emission of ZnSeTe QDs, are embedded in the hole transport layer (HTL) in solution-processed multilayered architecture. In an effort to experimentally find the proper separation between AuAg NPs and QD emitters toward achieving the maximal LSPR effect, the concentrations of AuAg NPs in the HTL and HTL thickness are individually controlled. The optimized AuAg NP-incorporated blue ZnSeTe QLEDs exhibit 19.7 and 20.3% enhancements in luminance and external quantum efficiency, respectively, compared with the device fabricated without AuAg NPs.