Near-unity photoluminescence quantum yield of quantum dots with thick and continuously graded shell
발표자
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초록
내용
Core/shell structures, chemical and electronic envelopment of emissive cores with wider band gap semiconductors, have been widely adopted for colloidal quantum dots (QDs) to improve photoluminescence quantum yield (PL QY) and chemical stability. Ceaseless efforts made over two decades have reached nearly unity PL QYs of QDs. And recently, continuously graded (cg-) structure has been proposed to detrimental multicarrier Auger decay that lowers performance of QD-based light-emitting diodes. However, PL QY of cg-QDs is necessarily limited up to ~70% due to interfacial defect originating from accumulated lattice strain. Here, we address that minute shell design allows us to attain near unity PL QY without loss of suppressed Auger decay. Multilateral analysis on strain and morphology development in the course of shell growth reveals that the lattice parameter management in shell phase is crucial to realize defect-free QDs despite gigantic shell thickness over 10 nm.