Encaged-anion tunable luminescence of Ce3 +-activated single host Ca12Al14O32Cl2 phosphor for UV pumped multi-color LEDs

• A novel tunable-light-emitting single-host Ca12Al14O32Cl2:0.5%Ce3 + phosphor has been prepared in H2 atmosphere.
• A large red-shift (from 434 to 503 nm) and an increased full width at half maximum can be observed.
• The emission of Ce3 + is tuned simply by controlling anions (O2 −, Cl−) in the nanocages.
• The CIE coordinates of the phosphor move from yellow to blue by increasing temperature from 293 to 623 K.

A novel tunable-light-emitting single-host Ca12Al14O32Cl2:0.5%Ce3 + phosphor has been prepared in H2 atmosphere by a solid-state reaction method. Upon 340 nm excitation, the phosphor shows an asymmetric broadband emission centered at 503 nm, assigned to the 5d-4f transitions of Ce3 +. For Ce3 + doped Ca12Al14O32Cl2, a large red-shift (~ 69 nm) and an increased full width at half maximum from 66 to 115 nm can be observed in comparison with that of the Ce3 + doped Ca12Al14O33 sample. In particular, the emission color of the Ca12Al14O32Cl2:0.5%Ce3 + phosphor can be tuned from blue to yellow by controlling anions in the nanocages, causing the different lattice deformations. Moreover, the CIE coordinates of the Ca12Al14O32Cl2:0.5%Ce3 + phosphor move from yellow to blue as the heating temperature increases from 293 to 623 K. Our results suggest that the encaged-anion modulation in combination with the heating is an effective strategy for realizing highly color tunable emission of Ce3 + doped in a single host, and furthermore, for designing novel phosphors for UV pumped multi-color LEDs and related devices.

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