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The Ce3+ → Tb3+ → Eu3+ energy-transfer process enables Eu3+5D0 → 7F J line emission to be sensitized by the allowed Ce3+ 4f1 → 5d1 absorption transition in near-ultraviolet (NUV) and violet spectral regions. This energy-transfer strategy is applied in Y2SiO5:Ce3+, Tb3+, Eu3+ powders, leading to line-emitting red phosphors that can be excited by short-wavelength InGaN LEDs. The blue, green, and red colors can be tuned by the ratio of Ce3+/Tb3+/Eu3+. Furthermore, the energy-transfer efficiencies and corresponding mechanisms are discussed in detail, and the thermal stability is evaluated. The results suggest that the optimal composition phosphor Y2SiO5: 0.01Ce3+, 0.50Tb3+, 0.01Eu3+, which exhibits an intense Eu3+ red 4f–4f sharp emission with a strong 4f–5d absorption band of Ce3+ at the NUV region, could serve as a potential broadband-excited and narrow line red phosphor for NUV LEDs.

Ba 1.8−x Sr x SiO 4 :0.1Ce 3+ ,0.1Na + (x = 0−1.8) phosphors were prepared by a high-temperature solid-state reaction. The emission peaks of Ba 1.8−x Sr x SiO 4 :0.1Ce 3+ ,0.1Na + shift from 391 to 411 nm with increasing Sr 2+ content under excitation by a UV light at around 360 nm. Ba 0.4 Sr 1.4 SiO 4 :0.1Ce 3+ ,0.1Na + phosphor exhibits the best performance of luminescence, whose absolute quantum efficiency is 97.2%, and the emission intensity at 150 °C remains 90% of that at room temperature. The effect of replacing Ba 2+ by Sr 2+ on the red shift of the emission band and the increase of quantum efficiency (QE) and thermal stability (TS) was investigated in detail based on the Rietveld refinements, Raman spectra, thermoluminescence, and decay curves, etc. The performance of UV chip-based pc-LEDs indicates that Ba 0.4 Sr 1.4 SiO 4 :0.1Ce 3+ ,0.1Na + can be a promising blue phosphor for white-emitting pc-LEDs.

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A series of NaCaBO3:Ce(3+),Tb(3+),Mn(2+) borate phosphors were prepared via a high-temperature solid-state reaction. The obtained phosphors exhibit a strong excitation band between 250 and 400 nm, matching well with the dominant emission band of a NUV light-emitting-diode (LED) chip. The phosphors can generate light from blue to green, and from blue to red by Ce(3+)→Tb(3+) and Ce(3+)→Mn(2+), respectively. Furthermore, a wide-range-tunable white light emission was obtained by precisely controlling the contents of Ce(3+), Mn(2+), Tb(3+). The results show that this phosphor has potential applications as a single-phased phosphor for NUV white LEDs.

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There is a challenge for noncontact temperature-sensing techniques and the related materials, in which a highly reliable contactless thermometer probe with low cost and high sensitivity is in demand. Here, the Lu3Al5O12:Ce3+/Mn4+ phosphor has been designed and prepared for the high-performance fluorescence temperature-sensing application in a novel one-pot, self-redox, solid-state process. Benefiting from the different electron–lattice/phonon interactions of Ce3+ and Mn4+, two distinguishable emission peaks with significantly different temperature responses originating from Ce3+ and Mn4+ are realized. Applying the fluorescence intensity ratio of Mn4+ versus Ce3+ and the decay lifetime of Mn4+ emission as the temperature readout, a dual-mode optical temperature-sensing mechanism was proposed and studied in the temperature range of 100–350 K. The maximum relative sensitivities (S r) are derived as 4.37 and 3.22% K–1 respectively, as well as a large chromaticity shift visible to naked eyes (ΔE = 153 × 10–3 in 100–350 K) is observed. This is the first report of a Ce3+,Mn4+ co-doped dual-emitting phosphor, and its unique optical thermometric features demonstrate the high potential of Lu3Al5O12:Ce3+/Mn4+ as an accurate and reliable thermometer probe candidate.

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