Enhanced thermal stability of InP quantum dots coated with Al-doped ZnS shell
- 관리정보기술 faculty
- 등재 SCIE, SCOPUS
- 발행기관 American Institute of Physics Inc.
- 발행년도 2019
- URI http://www.dcollection.net/handler/ewha/000000162335
- 본문언어 영어
- Published As http://dx.doi.org/10.1063/1.5121619
- PubMed https://pubmed.ncbi.nlm.nih.gov/31615236
- 저작권 이화여자대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Colloidal InP quantum dots (QDs) have attracted a surge of interest as environmentally friendly light-emitters in downconversion liquid crystal displays and light-emitting diodes (LEDs). A ZnS shell on InP-based core QDs has helped achieve high photoluminescence (PL) quantum yield (QY) and stability. Yet, due to the difficulty in the growth of a thick ZnS shell without crystalline defects, InP-based core/shell QDs show inferior stability against QY drop compared to Cd chalcogenide precedents, e.g., CdSe/CdS core/thick-shell QDs. In this work, we demonstrate the synthesis of InP-based core/shell QDs coated with an Al-doped ZnS outer shell. QDs with an Al-doped shell exhibit remarkable improvement in thermal and air stability even when the shell thickness is below 2 nm, while the absorption and PL spectra, size, and crystal structure are nearly the same as the case of QDs with a pristine ZnS shell. X-ray photoelectron spectroscopy reveals that Al3+ in Al-doped QDs forms an Al-oxide layer at elevated temperature under ambient atmosphere. The as-formed Al-oxide layer blocks the access of external oxidative species penetrating into QDs and prevents QDs from oxidative degradation. We also trace the chemical pathway of the incorporation of Al3+ into ZnS lattice during the shell growth. Furthermore, we fabricate QD-LEDs using Al-doped and undoped QDs and compare the optoelectronic characteristics and stability. © 2019 Author(s).
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