Effect of Ligand Exchange on the Photoluminescence Properties of Cu-Doped Zn-In-Se Quantum Dots

• Published in: Journal of electronic materials Vol. 47; no. 4; pp. 2241 - 2248
• Main Authors: Dong, Xiaofei, Xu, Jianping, Yang, Hui, Zhang, Xiaosong, Mo, Zhaojun, Shi, Shaobo, Li, Lan, Yin, Shougen
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.04.2018; Springer Nature B.V
• Subjects: Acoustic coupling; Characterization and Evaluation of Materials; Chemistry and Materials Science; Copper; Coupling (molecular); Electron microscopy; Electron transitions; Electronics and Microelectronics; Electrons; Exchanging; Fourier transforms; Instrumentation; Ligands; Mass spectrometry; Materials research; Materials Science; Melt temperature; NMR; Nuclear magnetic resonance; Optical and Electronic Materials; Photoluminescence; Quantum dots; Quenching; Solid State Physics; Transition temperature; Zinc; ligand density; photoluminescence; Cu-doped Zn-In-Se quantum dots
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-017-6050-3

The surface-bound ligands of a semiconductor nanocrystal can affect its electron transition behavior. We investigate the photoluminescence (PL) properties of Cu-doped Zn-In-Se quantum dots (QDs) through the exchange of oleylamine with 6-mercaptohexanol (MCH). Fourier transform infrared and 1 H nuclear magnetic resonance spectroscopies, and mass spectrometry reveal that the short-chain MCH molecules are bound to the QD surface. The emission peaks remain unchanged after ligand exchange, and the PL quantum yield is reduced from 49% to 38%. The effects of particle size and defect type on the change in PL behavior upon ligand substitution are excluded through high-resolution transmission electron microscopy, UV–Vis absorption, and PL spectroscopies. The origin of the decreased PL intensity is associated with increased ligand density and the stronger ligand electron-donating abilities of MCH-capped QDs that induce an increase in the nonradiative transition probability. A lower PL quenching transition temperature is observed for MCH-capped QDs and is associated with increasing electron-acoustic phonon coupling due to the lower melting temperature of MCH.