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Ce3+ doped CaAlSiN 3 is a promising broadband orange phosphor that can be applied in white light-emitting diodes (wLEDs) solid state lighting for general illumination. However, its emission color and quantum efficiency are not good enough to achieve high color rendering properties and luminous efficacy of wLEDs. In this work, we proposed to realize the spectral tuning and property enhancement of CaAlSiN 3 :Ce3+ by bandgap engineering via the cationic substitution of Ca by Sr. The relationship between photoluminescence and local coordination structure as well as electronic structure were revealed. The substitution led to a blue-shift in emission maximum by 13 nm (from 595 to 582 nm) and a highest external quantum efficiency of 55% (enhanced by 10%). This broadband yellow phosphor enabled to produce wLEDs with a color rendering index of 83.3, luminous efficacy of 114.6 l m/W and a color temperature of 4604 K. With the substitution of Ca by Sr in broadband yellow phosphor CaAlSiN 3 :Ce3+, a blue-shift in the emission maximum (from 595 to 582 nm) was attained, while the quantum efficiency and thermal stability of the phosphor containing 40% Sr were increased by 10 and 7.2% due to the decreased crystal field splitting and increased bandgap of the host. Image 1 • The bandgap engineering was adopted to realize the spectral tuning of CaAlSiN 3 :Ce3+ via the substitution of Ca by Sr. • The relationship between local structure and luminescence properties in Sr x Ca 1-x AlSiN 3 :Ce3+ was comprehensively discussed. • With the substitution, a blue-shift in the emission maximum (from 595 to 582 nm) was attained. • The quantum efficiency and thermal stability of the sample containing 40% Sr were raised by 10 and 7.2%, respectively. • This broadband yellow phosphor enabled to produce wLEDs with a color rendering index of 83.3. [ABSTRACT FROM AUTHOR]

The borate Ba 3 InB 9 O 18 (BIBO) is a promising host material for phosphors. A series of Tb 3+ and Eu 3+ codoped Ba 3 InB 9 O 18 phosphors were synthesized. Based on the Rietveld method, structure refinement of the codoped BIBO phosphor was carried out. Then, the luminescence properties of BIBO:Tb 3+ , Eu 3+ phosphors were extensively investigated under ultraviolet (UV) and vacuum ultraviolet (VUV) excitation. The measured PL spectra and decay times evidenced that energy transfer occurs between the Tb 3+ and Eu 3+ ions. The energy-transfer mechanism from Tb 3+ to Eu 3+ in Ba 3 InB 9 O 18 is dominated by electric multipolar interactions, with the critical distance calculated to be 10.97 Å. The temperature sensitivity of the Tb 3+ and Eu 3+ codoped sample under VUV was also investigated at the low temperature range from 25 K to 298 K. The emission color could be tuned from green to the red region by adjusting the concentration of codoped ions. The results indicate that the BIBO-based phosphors are valuable candidates for applications in the display and lighting fields., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)