Highly Luminescent Shell-Less Indium Phosphide Quantum Dots Enabled by Atomistically Tailored Surface States.

Contrary to the prevailing notion that shell structures arise from the intricate chemistry and surface defects of InP quantum dots (QDs), an innovative strategy that remarkably enhances the luminescence efficiency of core-only InP QDs to over 90% is introduced. This paradigm shift is achieved through the concurrent utilization of group 2 and 3 metal-derived ligands, providing an effective remedy for surface defects and facilitating charge recombination. Specifically, a combination of Zn carboxylate and Ga chloride is employed to address the undercoordination issues associated with In and P atoms, leading to the alleviation of in-gap trap states. The intricate interplay and proportional ratio between Ga- and Zn-containing ligands play pivotal roles in attaining record-high luminescence efficiency in core-only InP QDs, as successfully demonstrated across various sizes and color emissions. Moreover, the fabrication of electroluminescent devices relying solely on InP core emission opens a new direction in optoelectronics, demonstrating the potential of the approach not only in optoelectronic applications but also in catalysis or energy conversion by charge transfer.

Electrically Tunable Single Polaritonic Quantum Dot at Room Temperature.

Exciton-polaritons confined in plasmonic cavities are hybridized light-matter quasiparticles, with distinct optical characteristics compared to plasmons and excitons alone. Here, we demonstrate the electric tunability of a single polaritonic quantum dot operating at room temperature in electric-field tip-enhanced strong coupling spectroscopy. For a single quantum dot in the nanoplasmonic tip cavity with variable dc local electric field, we dynamically control the Rabi frequency with the corresponding polariton emission, crossing weak to strong coupling. We model the observed behaviors based on the quantum confined Stark effect in the strong coupling regime.

Bright and Stable Quantum Dot Light-Emitting Diodes.

Quantum dot light-emitting diodes (QLEDs) are one of the most promising candidates for next-generation displays and lighting sources, but they are barely used because vulnerability to electrical and thermal stresses precludes high brightness, efficiency, and stability at high current density (J) regimes. Here, bright and stable QLEDs on a Si substrate are demonstrated, expanding their potential application boundary over the present art. First, a tailored interface is granted to the quantum dots, maximizing the quantum yield and mitigating nonradiative Auger decay of the multiexcitons generated at high-J regimes. Second, a heat-endurable, top-emission device architecture is employed and optimized based on optical simulation to enhance the light outcoupling efficiency. The multilateral approaches realize that the red top-emitting QLEDs exhibit a maximum luminance of 3 300 000 cd m-2 , a current efficiency of 75.6 cd A-1 , and an operational lifetime of 125 000 000 h at an initial brightness of 100 cd m-2 , which are the highest of the values reported so far.