Metal Oxide-Induced Surface Trap-Filling in Quantum Dot Electroluminescent Devices
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초록
내용
Recently, metal oxide-based electron transport layers (ETLs) are widely adopted in quantum dot light-emitting diodes (QLEDs) due to their exceptional performance. Despite the success, the underlying mechanism responsible for the enhancement is controversial. Interestingly, QLED efficiencies often surpass theoretical limits envolped by the photoluminescence quantum yield, hinting at a concealed mechanism. Our studies shows the charge transfer between ZnO-based ETLs and QDs influences the optical properties of QDs. we analyze the carrier occupations in QDs on metal oxides using the ultrafast transient spectroscopy, allowing us to quantify the emissive probability. The surface trap-filling by metal oxides lead to a substantial increase in the emissive probability. Such electrobrightening phenomenon enhances QLED efficiency by mitigating intrinsic surface defects. Our findings pave the way for novel approaches to enhance the efficiency of QLEDs and advancing optoelectronics.