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Cyan-emitting Ca9NaGd2/3(PO4)7:Eu2+phosphors were synthesized via high temperature solid-state route. X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) were used to verify the phase and morphology of the Ca9NaGd2/3(PO4)7:Eu2+(CNGP:Eu2+) phosphors. The as-obtained phosphor exhibits a broad excitation band of 250–420 nm, which is near the ultraviolet region. An intense asymmetric cyan emission at 496 nm corresponds to the 5d-4f transition of Eu2+. The multiple-site luminescent properties of Eu2+ions in CNGP benefit from versatile structure of β-Ca3(PO4)2compounds. The effective energy transfer distance is 5.46 nm (through the spectral overlap calculation), validating that the resonant energy migration type is via dipole–dipole interaction mechanism. Compared to the initial one at room temperature, the luminescent intensity of CNGP:Eu2+phosphor can maintain 77% as it is heated up to 420 K. A white light-emitting diode (WLED) with excellent luminescent properties was successfully fabricated. Moreover, the CIE chromaticity coordinates of fabricated WLED driven by changing current just change slightly.

We report a high-yield synthesis of gold (Au) nanosheets with tunable size and surface morphology in the aqueous phase. In particular, crumpled and flat Au nanosheets with a thickness of ∼10 nm could be selectively produced in high purity when the reaction was conducted at room temperature and in an ice–water bath, respectively. Unlike Au nanoplates/nanoprisms in the form of well-defined triangles or hexagons documented in previous studies, the current products exhibit random in-plane branches or holes, together with wavy edges. Strong absorbance in the NIR region was observed for all the Au nanosheet products. When serving as electrocatalysts for the ethanol oxidation reaction, the current products exhibited an enhanced activity and operation stability, as compared to quasi-spherical counterparts.

We report the fabrication of concave gold (Au) nanocrystals with a set of morphologies and controlled sizes via seeded growth. Starting with Au seeds with a well-defined morphology and uniform size, cubic and rodlike Au nanocrystals with a noticeable concave feature could be successfully obtained, respectively. We also track the growth process and record the shape evolution process. The effect of several reaction parameters on product morphology, such as capping agent and concentration of Ag+, are systematically investigated. Their optical and electrochemical properties are investigated via UV–vis extinction spectroscopy and cyclic voltammetry, respectively. Compared to spherical counterparts, the current concave Au nanocrystals exhibit a noticeable red shift of the absorbance peak in UV–vis extinction spectra and characterized electrochemical behavior of stepped facets, illustrating the morphological advantage.

A new blue-emitting phosphor, SrLaGa3S6O:Ce3+, was prepared by a two-step high temperature solid-state reaction. X-ray powder diffraction analysis confirmed the formation of SrLaGa3S6O:Ce3+. The photoluminescence spectra showed that this phosphor can be excited efficiently by UV-visible light from 250 to 420 nm and emitted intensely blue light with two emission bands peaking at about 430 and 467 nm. The blue light-emitting LED with the CIE chromaticity coordinates of (0.152, 0.059) was successfully fabricated by precoating SrLaGa3S6O:Ce3+ phosphor onto a 398 nm-emitting InGaN chip. Its CIE chromaticity coordinates were almost the same as the NTSC standard values for blue. SrLaGa3S6O:Ce3+ could be a promising blue phosphor candidate for white LEDs.

An intense bluish-green phosphor, CaLaGa_3S_6O:Ce^3+,Tb^3+, is developed. The photoluminescence excitation and emission spectra, the lifetime, and the concentration effect are investigated. The results show that an efficient nonradiative energy transfer from Ce^3+ to Tb^3+ occurs and its efficiency is about 11%. Although the efficiency is not high enough, these results demonstrate that a Tb^3+ ion with low 4f–4f absorption efficiency in the near-UV [(n)-UV] region can play the role of activator in a narrow green-emitting phosphor. This is potentially useful in (n)-UV (380–420nm) GaN-based LEDs through efficient energy feeding by allowing 4f–5d absorption of Ce^3+ with high oscillator strength.

A near-infrared phosphor, Sr3SiO5:Ce3+,Yb3+, is developed as a potential solar spectral converter for Si solar cells. The diffuse reflection, photoluminescence excitation, and emission spectra at room temperature and at 3 K were investigated. These results show that the Sr3SiO5:Ce3+,Yb3+phosphor has broadband absorptions peaking at 415 nm which can efficiently facilitate the UV-blue part of the solar spectrum when compared with Sr3SiO5:Yb3+. Furthermore, it can give an intense emission around 1000 nm via an energy transfer process from Ce3+to Yb3+, matching well with the optimal spectral response of Si solar cells. The cooperative quantum cutting mechanism is also proposed.

A near-infrared phosphor, Sr3SiO5:Ce3+,Yb3+, is developed as a potential solar spectral converter for Si solar cells. The diffuse reflection, photoluminescence excitation, and emission spectra at room temperature and at 3 K were investigated. These results show that the Sr3SiO5:Ce3+,Yb3+ phosphor has broadband absorptions peaking at 415 nm which can efficiently facilitate the UV-blue part of the solar spectrum when compared with Sr3SiO5:Yb3+. Furthermore, it can give an intense emission around 1000 nm via an energy transfer process from Ce3+ to Yb3+, matching well with the optimal spectral response of Si solar cells. The cooperative quantum cutting mechanism is also proposed.

The title phosphor is synthesized by solid state reaction of CaS, La2S3, Ga2S3, and Ce2S3(Ar, 950 °C, 2 h) and characterized by powder XRD, SEM, and photoluminescence spectroscopy.

A new blue-emitting phosphor, SrLaGa3S6O:Ce3+, was prepared by a two-step high temperature solid-state reaction. X-ray powder diffraction analysis confirmed the formation of SrLaGa3S6O:Ce3+. The photoluminescence spectra showed that this phosphor can be excited efficiently by UV-visible light from 250 to 420 nm and emitted intensely blue light with two emission bands peaking at about 430 and 467 nm. The blue light-emitting LED with the CIE chromaticity coordinates of (0.152, 0.059) was successfully fabricated by precoating SrLaGa3S6O:Ce3+phosphor onto a 398 nm-emitting InGaN chip. Its CIE chromaticity coordinates were almost the same as the NTSC standard values for blue. SrLaGa3S6O:Ce3+could be a promising blue phosphor candidate for white LEDs.