Phosphine-Free-Synthesized ZnSe/ZnS Core/Shell Quantum Dots for White Light-Emitting Diodes

• Published in: Applied sciences Vol. 11; no. 21; p. 10060
• Main Authors: Byambasuren, Nyamsuren, Jo, Jiyeon, Ko, Hyungduk, Ju, Byeong-Kwon, Byun, Ji Young, Jang, Ho Seong
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.11.2021
• Subjects: Absorption spectroscopy; blue LED; Cadmium; core/shell structure; Crystallography; Gas flow; Ligands; Light emitting diodes; Optical properties; Paraffins; Photoluminescence; Photons; Quantum dots; Quantum efficiency; Spectrum analysis; Thermal decomposition; Transmission electron microscopy; warm white LED; White light; X-ray crystallography; Zinc oxides; Zinc selenide; Zinc sulfide; ZnSe/ZnS quantum dots
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app112110060

Blue-light-emitting ZnSe core (C) and ZnSe/ZnS core/shell (C/S) quantum dots (QDs) were synthesized with phosphine-free precursors by a thermal decomposition method in paraffin oil solvent and applied to QD-converted light-emitting diodes (LEDs). The optical properties of the synthesized ZnSe C and ZnSe/ZnS C/S QDs were characterized by absorption spectroscopy and photoluminescence spectroscopy. Additionally, the quantum efficiency of the QDs was investigated. Their structural properties were studied with X-ray crystallography and transmission electron microscopy. The ZnSe/ZnS C/S QDs showed deep-blue light peaking at 425 nm. The blue-light-emitting ZnSe/ZnS C/S QDs were used as color-converting materials for near-ultraviolet LED-pumped blue LEDs and combined with yellow-light-emitting Zn-Cu-In-S/ZnS C/S QDs to fabricate white LEDs. The white LEDs showed warm white light [(CIE x, CIE y) = (0.4088, 0.3987)], Tc = 3488 K, and Ra = 61.2]. The results indicate that the ZnSe/ZnS C/S QDs have good potential for white light application after further improvements to their optical properties.