Room‐Temperature Ionic‐Liquid‐Assisted Microwave Preparation of Tunable Photoluminescent Copper‐Indium‐Zinc‐Sulfide Quantum Dots

Abstract

A facile approach towards photoluminescent (PL) Cu-In-Zn-S quantum dots (CIZS QDs) has been developed, comprising microwave treatment with the assist of room-temperature ionic liquid (RTIL). Because of its high polarizability, RTIL served as a microwave absorbent, which resulted in the increase of the instantaneous nucleation rate and the rapid synthesis of CIZS QDs at low temperature. Moreover, the surface decoration of QDs with RTIL can passivate the surface defects greatly. The PL intensity of the CIZS QDs depends on the anion species, alkyl chain length of the RTIL, and the metal element ratios of the QDs. On the basis of the variable PL peak position and extended luminescence lifetime of the CIZS QDs, the superior emission behavior of the QDs was confirmed by surface etching with fluoride produced by the hydrolysis of RTIL 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF ). Moreover, the intermediate alkyl chain length of the RTIL can avoid aggregation, which results in the construction of CIZS QDs with homogenous size distribution. The shape-controlled CIZS QDs show a broadened tunable emission peak from 677 to 579 nm compared with that of QDs prepared by a conventional one-pot method by mixing the raw materials. CIZS QDs also exhibit a high quantum yield (QY) of 24.1 % after coating with a ZnS shell. This method is expected to be a useful technique for the rapid synthesis of multiple QDs with a wider range of emission wavelengths and higher QY for a variety of applications.

Ionic Liquids‐Assisted Highly Luminescent Copper Nanoclusters with Triangle Supramolecular Nanostructures

“…Over the last couple of decades, copper nanoclusters (CuNCs) have received great attentions due to desirable properties in terms of nontoxicity, [ 7 ] good stability, [ 11 ] great biocompatibility, [ 1 ] tunable fluorescent emission, [ 10 ] easy synthesis, [17] and so on. They have been applied to practical applications in ion sensing, [18] cell imaging [ 15 ] and other aspects.…”

Manganese Fluoride Nanoparticles Synthesized by Microwave Irradiation Using Ionic Liquid–Ethylene Glycol Mixtures: Room-Temperature Photoluminescence, Crystalline Phase, and Morphology

“…Ionic liquids, molten salts composed of organic cations and organic or inorganic anions, with characteristic melting points below 100 °C, have been widely studied as a new kind of reaction medium due to their unique physicochemical properties such as low viscosity, negligible vapor pressure, nonflammability, good thermal and chemical stability, and high ionic conductivity. , These characteristics of ionic liquids make them suitable as a microwave absorber. ,, Ionic liquids containing fluorine compounds also can be used as fluoride regents instead of toxic fluorine-containing compounds such as CF 3 COOH and HF for metal fluoride synthesis. − Metal fluoride nanostructures such as FeF 2 , CoF 2 , ZnF 2 , LaF 3 , YF 3 , MgF 2 , CaF 2 , SrF 2 , and CdF 2 have been synthesized by the microwave-assisted ionic liquid method. ,, …”

“…1−5 Compared to conventional heating, microwave-assisted synthesis has the advantages of rapid volumetric heating, higher chemical reaction rate and selectivity, shorter reaction time (generally, in a few minutes), and higher product yield. 1,2 For these reasons, over the past two decades, the microwave-assisted synthesis of inorganic nanostructured materials, such as metals, 6−8 metal oxides, 9,10 metal sulfides, 11 metal fluoride, 12−14 and others 15 has rapidly developed in various solvents such as water, 3 polyols like ethylene glycol, 6,7,11 and ionic liquids. 4,14,15 Ionic liquids, molten salts composed of organic cations and organic or inorganic anions, with characteristic melting points below 100 °C, have been widely studied as a new kind of reaction medium due to their unique physicochemical properties such as low viscosity, negligible vapor pressure, nonflammability, good thermal and chemical stability, and high ionic conductivity.…”

“…16,17 These characteristics of ionic liquids make them suitable as a microwave absorber. 4,14,15 Ionic liquids containing fluorine compounds also can be used as fluoride regents instead of toxic fluorine-containing compounds such as CF 3 COOH and HF for metal fluoride synthesis. 18−20 Metal fluoride nanostructures such as FeF 2 , CoF 2 , ZnF 2 , LaF 3 , YF 3 , MgF 2 , CaF 2 , SrF 2 , and CdF 2 have been synthesized by the microwave-assisted ionic liquid method.…”

“…Microwave irradiation in the liquid phase has been considered as a promising method for the synthesis of nanostructured inorganic materials. − Compared to conventional heating, microwave-assisted synthesis has the advantages of rapid volumetric heating, higher chemical reaction rate and selectivity, shorter reaction time (generally, in a few minutes), and higher product yield. , For these reasons, over the past two decades, the microwave-assisted synthesis of inorganic nanostructured materials, such as metals, − metal oxides, , metal sulfides, metal fluoride, − and others has rapidly developed in various solvents such as water, polyols like ethylene glycol, ,, and ionic liquids. ,, …”