Jiaqing Liu

Single-step noninjection synthesis of highly luminescent water soluble Cu+ doped CdS quantum dots: application as bio-imaging agents

Novel highly luminescent Cu(+) doped CdS quantum dots (QDs) were directly synthesized in aqueous phase through a facile single-step noninjection method. Due to their bright red fluorescence, ultrasmall size, and good biocompatibility, as-prepared CdS:Cu(+) QDs have potential as probes in bio-imaging.

Microwave synthesis of high luminescent aqueous CdSe/CdS/ZnS quantum dots for crystalline silicon solar cells with enhanced photovoltaic performance

Water-dispersed CdSe/CdS/ZnS core/shell/shell quantum dots (QDs) with the highest quantum yield of 25.4% were first synthesized for each component by microwave irradiation. As-prepared QDs do not only possess a large Stokes shift but also exhibit excellent repeatability. They can convert near UV and blue light with lower sensitivity to the Si solar cell to red light at which the solar cell has higher sensitivity. The fabricated CdSe/CdS/ZnS QDs/SiO2 composite films were applied to Si solar cells as luminescent down-shifting layers and the effect of QDs on the photoelectric conversion efficiency of photovoltaic modules was investigated. Under one sun illumination, the composite film containing an appropriate amount of CdSe/CdS/ZnS QDs effectively enhances the photoelectric conversion efficiency of the Si solar cell by spectral down-shifting as compared to the bare glass substrate, and the maximum achieves 16.14%.

One-pot synthesis of high quality CdS nanocrystals by microwave irradiation in an organic phase: a green route for mass production

High quality CdS nanocrystals emitting from 412 to 458 nm were synthesized by a simple one-pot noninjection microwave irradiation route using low-cost, air-stable CdO, S powder, 1-octadecene and oleic acid as the starting materials under air atmosphere. With simple variation of the reaction recipe (growth temperature and time), the absorption and emission wavelength, full width at half maximum (FWHM), and crystalline size of the resulting CdS quantum dots (QDs) can be conveniently tuned. The quantum yield of the as-prepared QDs at 240 °C for 30 min can be up to 33%. Compared with the traditional hot-injection approach, QDs synthesized by microwave heating are more efficient and the shortening of the reaction time leads to a high reaction yield. The use of microwave allows for a highly reproducible and effective synthesis protocol that is fully adaptable for mass production and can be easily employed to synthesize a variety of metal sulfide QDs.

Facile Synthesis of Cadmium-Free Zn-In-S:Ag/ZnS Nanocrystals for Bio-Imaging

High quality cadmium-free Zn-In-S:Ag doped-nanocrystals (d-NCs) were synthesized via a simple one-step noninjection route using silver nitrate, indium acetate, zinc acetate, oleylamine, S powder and 1-dodecanethiol as starting materials in an organic phase. The size and optical properties can be effectively tailored by controlling the reaction time, reaction temperature, Ag+ dopant concentration, and the molar ratio of In to Zn. The photoluminescence wavelength of as-prepared Zn-In-S:Ag NCs covered a broad visible range from 458 nm to 603 nm. After being passivated by protective ZnS shell, the photoluminescence quantum yield (PLQY) of Zn-In-S:Ag+ /ZnS was greatly improved to 43.5%. More importantly, the initial high PLQY of the obtained core/shell d-NCs in organic media can be preserved when being transferred into the aqueous media via ligand exchange. Finally, high quality Zn-In-S:Ag+ /ZnS d-NCs in aqueous phase were applied as bio-imaging agents for identifying living KB cells.

Air-exposing microwave-assisted synthesis of CuInS2/ZnS quantum dots for silicon solar cells with enhanced photovoltaic performance

Bright and photostable core/shell CuInS2/ZnS QDs with emission ranging from the red to NIR were synthesized in air via a simple one-pot microwave irradiation without any inert atmosphere protection. The as-prepared CIS/ZnS QDs not only possess a high PLQY (56%) but also exhibit a large Stokes shift. They can convert near UV and blue light with lower sensitivity to the Si solar cell to red and NIR light at which the solar cell has higher sensitivity. Especially, when they were first embedded into a polymethyl methacrylate (PMMA) transparent matrix to form a composite film as a luminescent down-shifting layer for Si solar cell, the photoelectric conversion efficiency of the cell shows a marked enhancement by spectral down-shifting as compared to the bare glass substrate, and the maximum achieves 16.21%.