Synthesis of luminescent semiconductor nanoparticles in ionic liquids –the importance of the ionic liquid in the formation of quantum dots

Abstract

Zinc sulfide (ZnS) and cadmium sulfide (CdS) nanoparticles were synthesized in different ionic liquids (IL) with microwave irradiation. Particle characterization by means of powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and optical spectroscopy (UV-vis absorption and photoluminescence) showed a strong dependence of the particle size depending on the IL employed. Whilst all ILs yielded particles in the nanometer regime and showed in their optical properties quantum confinement, particularly small particles were obtained from choline-base ILs pointing to the strong influence of this IL cation in blocking the particle growth. Here, quantum dots of 1.5-3 nm size were yielded for both, ZnS and CdS.

Ionic liquids and deep eutectics as a transformative platform for the synthesis of nanomaterials

“…111 Similarly, certain cations such as [cholinium] + yield extremely small ZnS nanoparticles, due to strong surface coordination which blocks crystal growth. 112 This method therefore allows for the fast and facile preparation of metals, metal chalcogenides as well as halide materials, and even convoluted multinary compounds such as ternary and complex oxides. 98–101…”

“…111 Similarly, certain cations such as [cholinium] + yield extremely small of prepared ZnS nanoparticles due to strong surface coordination which blocks crystal growth. 112 This method therefore allows for the fast and facile preparation of metals, metal chalcogenides as well as halide materials, and even convoluted multinary compounds such as ternary and complex oxides. [98][99][100][101] Ultrasound Assisted Synthesis Sonochemistry, albeit mostly in conventional and volatile solvents, has attracted increasing interest over the past decade for the synthesis of inorganic nanostructured materials.…”

Deep Eutectic Solvent-Assisted Microwave Synthesis of Thermoelectric AgBiS2 and Cu3BiS3

“…Ionic liquids are salts with melting points at or below 100 °C. Due to their low vapor pressure, low melting point, and high degree of tunability, ionic liquids have been widely explored as solvents in the synthesis of various materials. − Deep eutectic solvents (DESs) are analogues of ionic liquids, even though DESs contain not only ionic but also molecular entities in the liquid form. DESs are made of hydrogen bond donors and quaternary ammonium salts, such as choline chloride, which act as hydrogen bond acceptors. − Like ionic liquids, DESs possess low vapor pressure and low melting point, and there are a vast array of individual components from which they can be made .…”

The utilization of quantum dot labeling as a burgeoning technique in the field of biological imaging

“… 6 To counteract this biotoxicity, 7 a common approach has been to encapsulate the core with a protective shell composed of materials like ZnS, ZnSe, or a CdS/ZnS hybrid. 8 This not only significantly enhances luminescence efficiency but also acts as a barrier, preventing the release of toxic heavy metal ions. 9 Nevertheless, it is important to note that the intracellular environment, particularly within cell lysosomes, is acidic, which means that the protective shell is not fully effective in inhibiting the release of cadmium ions, leading to a limited protective effect.…”