Highly photoluminescent ZnSe/ZnS quantum dots

Abstract

ZnSe quantum dots have been synthesized using a simple aqueous route. Coating ZnSe quantum dots with a ZnS monolayer, yields a remarkable enhancement in the PL quantum efficiency at room temperature without affecting the spectral distribution. The results suggest that passivation of surface states, along with an increased localization of the hole in core ZnSe layer, gives rise to high luminescence quantum yield.

Synthesis of highly fluorescent glutathione-capped ZnxHg1−xSe quantum dot and its application for sensing copper ion

“…More importantly, after the ligand exchange, their QYs drop from 65-85% in the growth solution to 30-50% in the aqueous solution [4,5]. Hence, an aqueous synthesis using thiols as stabilizers has been suggested as a promising alternative for producing water-soluble QDs; however, these QDs suffer from low QYs and broad emissions [6,7]. Although the QYs of the thiol-capped QDs can be significantly enhanced by post-preparative treatments such as size-selective precipitation [8], change in the solution properties (e.g., pH) [9], and photochemical etching [10,11]; unfortunately, the aggregation of the QDs is easily induced during such treatments.…”

Photoluminescence of ZnSe nanocrystals at high excitation level

“…At the same time the semiconductor compound which has received the most intense interest in previous years has been ZnSe known to have a room temperature direct band gap of 2,7 eV that corresponds to emission in the blue region of the spectrum. Properly tailored ZnSe-based QD are well suited for short wavelength light emitters, a fact recognized worldwide by research groups several of whom have expanded a great deal of effort attempting to produce ZnSe NC of high quality [2,3]. However properties of extremely small ZnSe crystals under intense optical excitation remain unexplored and require better insight.…”

Synthesis and properties of colloidal ternary ZnGa2O4:Eu3+ nanocrystals

“…This technique has been demonstrated for binary semiconductor (e.g., CdSe [1], ZnSe [2], and PbSe [3]) and binary transition metal oxide (e.g., ZnO [4], TiO 2 [5], MnO [6], Fe 3 O 4 [7], and Gd 2 O 3 [8]) nanocrystals. Recently, this route was expanded to the synthesis of ternary nanocrystals with a controlled stoichiometry.…”

“…After repeated purifications with ethanol, purified ZnGa 2 O 4 :Eu 3+ nanocrystals were well dispersed in organic solvents such as hexane, chloroform, or toluene. In addition to Zn(acac) 2 and Ga(acac) 3 , other Zn and Ga precursors, such as Zn(II) acetate hydrate, Zn(II) acetate dehydrate, and Ga(III) nitrate hydrate, were used to investigate the effects of different precursors on the size and shape of ZnGa 2 O 4 :Eu 3+ nanocrystals, keeping other experimental parameters the same. Likewise, the effect of the type of the main surfactant was examined by changing from HDD (5 mmol) to TOPO (2 mmol).…”