A series of double-perovskite orange–red-emitting Ca (3−2 x ) Sm x Na x TeO 6 ( x = 0.01–0.25) phosphors have been synthesized via high-temperature method. The single-phase and orthorhombic structure of Ca 3 TeO 6 :Sm 3+ , Na + phosphors was confirmed by X-ray powder diffraction. Under 405 nm excitation, Ca 3 TeO 6 :Sm 3+ , Na + phosphors emitted a series of orange–red emission due to the transition of Sm 3+ from 4 G 5/2 to 6 H J/2 ( J = 5, 7, 9, and 11). The optimal Sm 3+ -doping concentration of Ca (3−2 x ) Sm x Na x TeO 6 ( x = 0.01–0.25) was x = 0.10. The thermal-quenching temperature of Ca 3 TeO 6 :0.10Sm 3+ , 0.10Na + phosphor was above 480 K. A white light-emitting diode (w-LED) based on 410 nm UV chip was successfully fabricated, and it presented a good correlated color temperature and a high color-rendering index (R a ). Therefore, orange–red-emitting Ca 3 TeO 6 :Sm 3+ , Na + phosphors have potential applications in UV-based w-LEDs.
X. Zhou,M.-H. Zhao,J. Yang,Y. Han,L. Cao,Y.-Y. Han,J. Wang,Y. Wang,M.-R. Li
Environment-friendly and cost-effective versatile yellow-green inorganic pigments are technically significant for natural camouflage but rare. Here, we adopt site-selective parent-doping of Mn–Li into the octahedral Ca-site (Ca B ) of Ca 3 TeO 6 to deliver vivid greenish pigments by the unprecedented yellow-green Mn 4+ O 6 chromophore, yielding tunable pigments resemble to seasonal leaves. The camouflage color zone of these pigments are remarkably enlarged by chemical pressure via Mg 2+ /Sr 2+ -substitution for the A -site Ca (Ca A ). The locally anisotropic and positive chemical pressure on chromophore group is scaled to be around +14.4/+23.3 GPa, as estimated from the accompanied geometric evolution of Mn 4+ O 6 . The achieved pigments also demonstrate excellent chemical and thermodynamic stability and high (60–80%) near infrared reflectivity in 1500–2500 nm, showing potential applications for natural camouflage and yellow-green “cool pigments”. These findings built a bridge between chemical and equivalently physical pressure, and nominated a way to estimate the overall and local strain/pressure by optical descriptor.
危险品化学品经营许可证（带存储）