High Efficiency over 15% by Breaking the Theoretical Efficiency Limit of Fluorescent Organic Light-Emitting Diodes with Localized Surface Plasmon Resonance Effects.

The theoretical efficiency limit of fluorescence organic light-emitting diodes (OLEDs) was successfully surpassed by utilizing the localized surface plasmon resonance (LSPR) effect with conventional emissive materials. The interaction between polaritons and plexcitons generated during the LSPR process was also analyzed experimentally. As a result, the external quantum efficiency (EQE) increased dramatically from 6.01 to 15.43%, significantly exceeding the theoretical efficiency limit of fluorescent OLEDs. Additionally, we introduced a new concept of the LSPR effect, called "LSPR sensitizer", which allowed for simultaneous improvement in color conversion and efficiency through cascade transfer of the LSPR effect. To the best of our knowledge, the EQE and the current efficiency of our LSPR-OLED are the highest among LSPR-based fluorescent OLEDs to date.

Effective Blue Light-Absorbing AuAg Nanoparticles in InP Quantum Dots-Based Color Conversion.

In typical color-by-blue mode-based quantum dot (QD) display devices, only part of the blue excitation light is absorbed by QD emitters, thus it is accompanied by the leakage of blue light through the devices. To address this issue, we offer, for the first time, the applicability of AuAg alloy nanoparticles (NPs) as effective blue light absorbers in InP QD-based color-by-blue platforms. For this, high-quality fluorescent green and red InP QDs with a double shell scheme of ZnSe/ZnS were synthesized and embedded in a transparent polymer film. Separately, a series of Au/Ag ratio-varied AuAg NPs with tunable plasmonic absorption peaks were synthesized. Among them, AuAg NPs possessing the most appropriate absorption peak with respect to spectral overlap with blue emission are chosen for the subsequent preparation of AuAg NP polymeric films with varied NP concentrations. A stack of AuAg NP polymeric film on top of InP QD film is then placed remotely on a blue light-emitting diode, successfully resulting in systematically progressive suppression of blue light leakage with increasing AuAg NP concentration. Furthermore, the beneficial function of the AuAg NP polymeric overlayer in mitigating undesirable QD excitation upon exposure to ambient lights was further examined.