Presentation Information
[TuA2-02]Rethinking Electroluminescence in ZnS:Cu ACELs: Why Are Crystal Defects a Fundamental Prerequisite for Light Emission?
〇Roberto Hernandez1,3, Lorenzo Rigutti2, Jonathan Houard2, Ludovic Largeau1, Stefano Pirotta1, Nathaniel Findling1, Francois Julien1, Jules Duraz1, Sidahmed Beddar3, Maria Tchernycheva1 (1. Centre de Nanosciences et de Nanotechnologies (C2N), UMR 9001 CNRS, Univ. Paris-Saclay (France), 2. UNIROUEN, CNRS, Groupe de Physique des Matériaux, Univ. Normandie (France), 3. Valeo Vision (France))
ZnS:Cu powders are vital for low-cost, large-area flexible electronics; however, a full understanding of their light-emission mechanism has remained elusive for nearly a century. While traditional models attributed Alternating Current Electroluminescence (ACEL) to copper precipitates or segregation at defects, we provide experimental evidence that decisively refutes these theories.
In this work, we resolve this long-standing uncertainty through pioneering nanoscale analysis using correlative Atom Probe Tomography (APT) and Transmission Electron Microscopy (TEM). We reveal a stochastic copper distribution, proving that Cu segregation is not the driver of emission. Instead, we identify Zincblende-Wurtzite (ZB-WZ) superlattices as the fundamental prerequisite for electroluminescence. Our findings show that EL is strictly governed by these internal structural defects, distinguishing it from photoluminescence or cathodoluminescence pathways.
We propose a novel mechanism where alternating ZB and WZ phases generate built-in electric fields. These arise from spontaneous polarization in the hexagonal phase and the band gap offset between structures, facilitating carrier recombination. By shifting the paradigm from chemical impurities to structural defect-driven physics, we provide a transformative roadmap for next-generation, large-area deformable light sources.
In this work, we resolve this long-standing uncertainty through pioneering nanoscale analysis using correlative Atom Probe Tomography (APT) and Transmission Electron Microscopy (TEM). We reveal a stochastic copper distribution, proving that Cu segregation is not the driver of emission. Instead, we identify Zincblende-Wurtzite (ZB-WZ) superlattices as the fundamental prerequisite for electroluminescence. Our findings show that EL is strictly governed by these internal structural defects, distinguishing it from photoluminescence or cathodoluminescence pathways.
We propose a novel mechanism where alternating ZB and WZ phases generate built-in electric fields. These arise from spontaneous polarization in the hexagonal phase and the band gap offset between structures, facilitating carrier recombination. By shifting the paradigm from chemical impurities to structural defect-driven physics, we provide a transformative roadmap for next-generation, large-area deformable light sources.
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