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Red phosphors of Li-doped CaTiO3:Eu3+ that enhance photoluminescence have been synthesized by a solid-state method, and their structure and morphology were confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The luminescence property was measured using photoluminescence excitation (PLE) and photoluminescence (PL) spectra, respectively. The effect of sintered temperature and Eu3+ and Li+ concentration in as-prepared series phosphors was studied. Results indicate that the optimal luminescence properties of CaTiO3:Eu3+ (CTE) phosphors are typically obtained at 1300 °C with 12 mol% of Eu3+ concentration, and the emission intensity can be greatly enhanced by the incorporation of Li+ into the CTE phosphors, attributing that Li not only compensates positive charge defect by replacement of Ca2+ with Eu3+, but also plays a role of flux, which could enhance the crystallinity of the phosphors. The intensity of the optimal Li-doped CaTiO3:Eu3+ phosphor (CLTE) is 2.3 times of that of CTE. PL spectrum showed that CLTE phosphor was efficiently excited by near-ultraviolet light at wavelength around 398 nm and emitted intensive red light with a peak around 616 nm corresponding to the 5D0→7F2 transition of Eu3+. Furthermore, this phosphor has very good thermal stability and high color purity, implying the potential to be a promising red phosphor in white light emitting diodes. [ABSTRACT FROM AUTHOR]

This paper reports a low-cost yellow-orange emitting Y3Al5−xSixO12−xNx:Ce3+ phosphor with excellent color rendering for warm white LEDs. It was synthesized by a simple gas pressure sintering (GPS). The effect of Si4+—N3− incorporation on the optical properties of Y3Al5O12:Ce3+ phosphor was investigated. The addition of Si3N4 leads to an obvious shift of its emission spectra toward the red region and an increase of FWHM accompanying a significant decrease of photoluminescent intensity, which is assigned to incorporation of N3− in Ce3+ nearest neighbor coordination. Adding nanosized amorphous Si3N4 or flux can greatly improve the emission intensity of Y2.925Ce0.075Al5−xSixO12−xNx phosphor. Finally, the white LED flat lamp with a CRI as high as 83, luminous efficiency of 65 lm/W, and CCT of about 3700 K is successfully realized by using a single oxynitride phosphor combined with a blue LED chip, which is acceptable for general indoor illuminations to replace fluorescent or incandescent lamps. [ABSTRACT FROM AUTHOR]