The Effect Of Benzenethiol Ligand On Cdse / Zns Core / Shell Quantum Dots

985 Words Sep 3rd, 2015 4 Pages
In this study, the effect of benzenethiol ligand on CdSe/ZnS core/shell quantum dots was investigated. Conventional long-chain oleic acid (OA) and trioctylphosphine (TOP) capping ligands were partially replaced by short benzenethiol ligands, and the improvement in the luminescence performance was observed in quantum dot light emitting diodes (QD-LED). Approximately 1.8 fold improvement was achieved for both the maximum luminance and maximum current efficiency for the QD-LEDs fabricated with bezenethiol ligand QDs. The turn-on voltage was reduced by ∼0.6 V by shifting the energy level of QDs with the benzenethiol ligands when compared to the conventional OA and TOP ligands. The mobility of the QD film approximately doubled to 2.42 x 10-5 cm2/V·S from 1.19 x 10-5cm2/V·S and the quantum yield of the QDs solution were 80% from 40%, respectively. The stability during the purification processes was also found to be improved.

I. Introduction
Colloidal quantum dots (QDs) are considered as promising light emitting materials owing to their superior optical properties such as broad absorption, narrow emission bandwidth, and easy control of the emission peak wavelength.[1–5] The performances of colloidal QD light emitting diodes (QD-LED) are rapidly improving in terms of brightness and external quantum efficiency with the development of high quantum yield QD and with the improvement of charge transfer layers. For example, metal oxide charge transfer materials such as ZnO nanoparticles…

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