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• Negative thermal expansion of PbTiO 3 compound is tailored by simultaneous substitution at the Pb and Ti sites. • The choice of substitutional elements with appropriate proportions produces materials with very low thermal expansion. • PT-L, and PT-N shows very low thermal expansion in the temperature regions, 15–400 K, and 15–420 K, respectively. • PT-P shows intermediate thermal expansion in the temperature range 15–380 K. [Display omitted] The article deals with the thermal expansion properties of some diluted PbTiO 3 (PT) based ceramic compounds. We have tailored the negative thermal expansion (NTE) coefficient of PT by substituting both at the Pb and Ti sites with different elements, with an intention to achieve very low thermal expansion coefficient. The choice of substitutional elements with appropriate proportions gives us materials with very low thermal expansion, operative over a wide range of temperature (from well above the room temperature to well below it). Moreover, we have shown an effective way to select the operative temperature region of their performance, even without performing the actual dilatometric experiment. [ABSTRACT FROM AUTHOR]

• Cs 2 KCrF 6 :Mn4+ was designed and prepared at mild conditions. • Cs 2 KCrF 6 :Mn4+ exhibits high blue-light conversion efficiency. • Cs 2 KCrF 6 :Mn4+ has excellently thermal quenching property and color stability. • Cs 2 KCrF 6 :Mn4+ can improve the luminescent performances of w-LED. One red phosphor Cs 2 KCrF 6 :Mn4+ (CKCFM) with the cubic structure was prepared at mild conditions. Mn4+ in CKCFM with the highly symmetrical environment exhibit one broad excitation band peaking at 453 nm and narrow-band emission in the range from 600 to 650 nm. The optimized CKCFM has one highly external quantum yield of 46.7%. At the same time, the sample also has excellent thermal stability and color stability. The emission intensity of CKCFM at 160 °C is still higher than that at 20 °C. At last, one white light-emitting diode (w-LED) was obtained by combining CKCFM and Y 3 Al 5 O 12 :Ce3+with one blue LED chip. It shows excellent performance: color rendering index (Ra) up to 88.3, color temperature (CCT) down to 3986 K, showing that CKCFM can find application in w-LEDs. New red-emitting phosphor Cs 2 KCrF 6 :Mn4+ exhibits high blue-light conversion efficiency and a high thermal-quenching temperature for w-LEDs. [Display omitted] [ABSTRACT FROM AUTHOR]