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An effective path to synthesize Znx Cd1-x S quantum dots (ZCS QDs) in aqueous phase at room temperature has remained relatively unexplored. Here, we developed a room-temperature, aqueous-phase approach to ZCS QDs, using 3-mercaptopropionic acid (MPA) to adjust the pH of the reaction precursor solution to regulate the competition between sulfur source and hydroxyl group, and realize the large-scale preparation of water-soluble ZCS QDs photocatalyst at room temperature. Without recombination with other materials, and only by regulating the ratio of pH, excess sulfur sources and Zn/Cd, the photocatalytic degradation of rhodamine B (RhB) can reach 98% within 1 min, showing high photocatalytic activity. ZCS QDs show high stability and recoverability, and are expected to be able to deal with organic pollutants on a large scale. This study provides a new idea for the preparation of other QDs at room temperature.

We present a facile route for the synthesis of water-soluble Cu–Cd–Zn–S/ZnS core/shell quantum dots (QDs) by simple pH regulation. The PL spectra of Cu–Cd–Zn–S/ZnS core/shell quantum dots can cover the whole visible light region in the case of only two ratios of Cu/Cd/Zn. The emission wavelength of Cu–Cd–Zn–S/ZnS QDs can be conveniently tuned from 474 to 515 and 548 to 629 nm by adjusting the pH value when the ratios of Cu/Cd/Zn are fixed at 1 : 5 : 80 and 1 : 5 : 10, respectively. It is worth noting that under the condition of a constant Cu/Cd/Zn ratio, the UV-vis absorption spectra do not change with the fluorescence spectra, indicating that the band gap of QDs remains unchanged during the change of pH value. The photoluminescence (PL) quantum yield of the as-prepared QDs with yellow emission is up to 76%. The QDs also show excellent chemical stability after the deposition of the ZnS shell. Luminescent and flexible films are fabricated by combining Cu–Cd–Zn–S QDs with polyvinyl alcohol (PVA). The QD/PVA flexible hybrid films are successfully applied on top of a conventional blue InGaN chip for remote-type warm-white LEDs. As-fabricated warm-white LEDs exhibit a higher color rendering index (CRI) of about 89.2 and a correlated color temperature (CCT) of 4308 K.

High-quality water-soluble Ag-In-S/ZnS core/shell quantum dots have been successfully synthesized via a facile and green method, with mercaptosuccinic acid and sodium citrate as dual ligands in one pot. The fabricated quantum dots exhibit excellent optical characteristics, including photoluminescence quantum yield (PLQY) of up to 50%, and the obvious first excition absorption peak. The emission peak of Ag-In-S/ZnS core/shell quantum dots can be tuned from 507 to 580 nm which covers the most of the visible light. Finally, the as-prepared Ag-In-S core quantum dots can be used directly in ion probe, achieved the direct visual inspection of Pb2+.

We present a facile route for the fabrication of P-type Cu x S transparent and conducting thin films (TCTFs) using copper (I) oxide and butyl-dithiocarbamic acid as precursors by pulling method on glass. The as-deposited highly conductive crystalline Cu x S films showed high carrier concentration (∼3.11 × 10 22 cm −3 ), low electrical resistivity (∼1.02 × 10 −4 Ω cm) and conclusive p-type conduction. X-ray diffraction studies showed high crystallinity, and the optical transmission spectra in UV–vis–NIR region of such films were recorded, indicating that the transparency was over 75% with a band gap of 1.52 eV. The room-temperature sheet resistance increased from 9.9 to 302.4 Ω sq −1 with increasing baking temperature. The Cu x S/quantum dot bifacial thin films have been fabricated, and the experimental results indicated that luminescent, transparent, and conductive Cu x S/Cu-doped Zn y Cd 1-y S thin films have a very high potential application in thin film solar cells.

Aqueous solution deposition of metal chalcogenide semiconductor thin films is considered a green and low-cost approach. So it is hard to find a general aqueous solution approach to deposit various kinds of high-quality metal sulfide quantum dots thin films. Here, we describe a green and robust aqueous solution approach, and five types of metal sulfide precursor solutions (Cu(CH 3 COO) 2 , AgNO 3 , Zn(CH 3 COO) 2 , Cd(CH 3 COO) 2 ·2H 2 O, Ni(CH 3 COO) 2 ·4H 2 O) can be prepared at room temperature under air atmosphere. By this green route, luminescent Ag-doped Zn x Cd 1− x S semiconductor films have been successfully synthesized via a facile and green method in the open air at 260 °C using precursors. NH 3 ·H 2 O (28–30%) were used as solvent, and 3-mercaptopropionic acid was used as the capping agents. As-prepared quantum dot thin films exhibit a tunable emission covering the whole visible light region. The absolute photoluminescence quantum yields can reach as high as 24.6%, which have a high potential application in luminescent, transparent, and conductive thin films.

Luminescent Cu-doped ZnxCd1-xS quantum dot thin films have been directly fabricated via a facile solution method in open air. Cu2O, ZnO, and Cd(OH)2 were used as starting materials, and 3-mercaptopropionic acid was used as the capping agent. The effects of Cu dopant concentration, sintering temperature, and sintering time on the photoluminescence properties of Cu-doped ZnxCd1-xS nanocrystal thin films have been systematically investigated. As-prepared quantum dot thin films exhibit tunable emission covering the whole visible light region and the absolute photoluminescence quantum yields can reach as high as 25.5%, which have high potential for applications in luminescent, transparent, and conductive thin films.

Water-soluble Cu+- and Ag+-doped ZnxCd1−xS quantum dots have been successfully synthesized via a facile and green method. All synthetic procedures were conducted in the open air at 95 °C. Hydrophilic glutathione was used as the capping agent. The influence of the dopant concentration in alloyed ZnxCd1−xS QDs has been investigated. The as-prepared Cu+- and Ag+-doped ZnxCd1−xS/ZnS core–shell quantum dots exhibit tunable emission covering the whole visible light region and the photoluminescence quantum yield (PL QY) can reach as high as 20% and 31%, respectively.

Cu2SnSe3 nanocrystals with a metastable zincblende and wurtzite structure have been successfully synthesized. The crystal structures were confirmed by means of X-ray diffraction and selected area electron diffraction. The lattice mismatch between Cu2SnSe3 and ZnSe is only 0.26%, thus homogeneously alloyed (ZnSe)(x)(Cu2SnSe3)(1-x) nanocrystals could be synthesized. The band gaps of nanocrystals can be tuned in a wide range of 2.75 to 0.92 eV; however the bowing parameter as high as 19.1 eV for alloyed (ZnSe)(x)(Cu2SnSe3)(1-x) nanocrystals was observed. These low cost and dispersible alloyed (ZnSe)(x)(Cu2SnSe3)(1-x) nanocrystals with a targeted band gap have a high potential in thin film solar cells. (C) 2012 Elsevier B.V. All rights reserved.

We report an electric pressure cooker for large-scale synthesis of water-soluble Cu–In–S/ZnS core/shell quantum dots. Low-cost thioglycolic acid and sodium citrate were used as the dual stabilizers. ∼3 grams of quantum dots with a tunable emission from 545 to 610 nm and quantum yield up to 40% were obtained in a batch.

Water-soluble Cu–In–S/ZnS core/shell quantum dots with a photoluminescence quantum yield up to 38% and an emission peak tunable from 543 to 625 nm have been successfully synthesized. All of the synthetic procedures were conducted in an aqueous solution at 95 °C under open-air conditions. l-Glutathione and sodium citrate were used as the dual stabilizing agents to balance the reactivity between copper and indium ions.

Metastable zinc blende CuInSe(2) nanocrystals were synthesized by a hot-injection approach. It was found that the lattice mismatches between zinc blende CuInSe(2) and ZnSe as well as CuInSe(2) and CuInS(2) are only 2.0% and 4.6%, respectively. Thus, alloyed (ZnSe)(x)(CuInSe(2))(1-x) and CuInSe(x)S(2-x) nanocrystals with a zinc blende structure have been successfully synthesized over the entire composition range, and the band gaps of alloys can be tuned in the range from 2.82 to 0.96 eV and 1.43 to 0.98 eV, respectively. These alloyed (ZnSe)(x)(CuInSe(2))(1-x) and CuInSe(x)S(2-x) nanocrystals with a broad tunable band gap have a high potential for photovoltaic and photocatalytic applications.

Au+ ions have been successfully incorporated into the lattice of ZnxCd1−xS quantum dots as luminescent centers via an aqueous method. The dopant emission can be tuned in the range of 445 to 570 nm, and the highest quantum yield can reach as high as 30%. Our results showed that Au+ ions can be used as an excellent luminescent dopant in doped quantum dots. Finally, these water-soluble quantum dots can be used directly in PL imaging of HepG2 cells without conjugating any biological targets, indicating a high potential application in bio-labeling.

We present a simple continuous-flow reaction for the synthesis of quaternary Cu-In-Zn-S/ZnS and Ag-In-Zn-S/ZnS core/shell quantum dots (QDs) using inexpensive and low-toxic precursors. The composition and band gap of Cu-In-Zn-S and Ag-In-Zn-S QDs were well controlled by changing the molar ratios of the starting materials. The PL quantum yields of Cu-In-Zn-S/ZnS core/shell quantum dots can reach as high as 40%.