Highly Luminescent ZnO Quantum Dots Made in a Nonthermal Plasma

Abstract

Nonthermal plasmas allow the preparation of ligand‐free quantum dots combining high production rates with superior crystalline quality and luminescence properties. Here, ZnO quantum dots are produced in a radiofrequency capacitively‐coupled plasma, exhibiting size dependent photoluminescent quantum yields up to 60% after air exposure—the highest reported to date for any compound semiconductor quantum dots prepared in the gas phase. Systematic studies indicate the importance of the surface for the observed luminescence behavior. The high luminescent quantum yields in the visible range of the spectrum and the ligand‐free, scalable synthesis make these quantum dots good candidates for light emitting applications.

Surface modified Mg-doped ZnO QDs for biological imaging

“…For instance, correlations have been observed between the presence of surface hydroxide moieties and visible luminescence intensity. As observed by Felbier et al, when surface oxygen containing species, such as OH groups, were desorbed under vacuum, the visible emission vanished while the UV emission was significantly enhanced (49). Of note, the decrease in QY when Mg-doped QDs are capped by oleic acid is consistent with the hypothesis of the role of OH groups in visible emission.…”

High electron mobility in thin films formed via supersonic impact deposition of nanocrystals synthesized in nonthermal plasmas

“…Zinc oxide nanocrystals were synthesized in the two-stage plasma reactor 13,14 illustrated in Supplementary Fig. 1.…”

Enhanced Red Emission in Ultrasound‐Assisted Sol‐Gel Derived ZnO/PMMA Nanocomposite

“…Zinc oxide (ZnO) is a n-type semiconducting material with a great application potential as electron conduit in (opto) electronic devices [1,2], photocatalysts [3,4], and photoluminescence materials [5,6]. ere are several methods for the synthesis of ZnO nanostructures, including sol-gel method, controlled precipitation, solvothermal techniques, microemulsion, and sonochemical treatments [7].…”

“…e visible emission is usually attributed to various recombination pathways between photoexcited charges being trapped at defect states within the bandgap. Although the chemical origin of defect states is still controversial [5,[13][14][15], surface modification has been widely used to control over the visible emission of ZnO, especially in ZnO nanostructures. Patrick Felbier and coworkers controlled air exposure of plasma-synthesized ZnO nanoparticles (NPs) to switch the emission from UV to yellow or green with a quantum yield of 60% [5].…”