Xiaoshuai Zhang,Wen Xiong,Chengrun Liu,Zixuan Wang,Xiaoyan Yu,Xiaojie Li,Guodong Zhang,Panlai Li,Zhijun Wang
Exploring oxide-based deep red light-emitting phosphors is crucial for indoor plant lighting applications. In particular, designing Eu 2+ deep red emission in inorganic solids is challenging. In this paper, a cation substitution strategy was used to replace the Ca 2+ ions in the matrix with a certain concentration of Sr 2+ ions. A series of spectrally red-shifted Ca 1-x Sr x Sc 2 O 4 :Eu 2+ deep red phosphors were obtained under 460 nm light excitation. The substitution of Sr 2+ ions changes the local crystal field environment of Eu 2+ . The spectral shift from 656 nm to 702 nm was achieved by changing the centroid shift, the degree of polyhedral distortion and the lattice disorder. Combined with the need for practical applications, Ca 0.5 Sr 0.5 Sc 2 O 4 :0.01Eu 2+ phosphor and blue chip have been made into phosphor-converted light-emitting diodes for plant lighting, and the results of plant lighting experiments show that Ca 0.5 Sr 0.5 Sc 2 O 4 :0.01Eu 2+ phosphor has a certain application potential in plant lighting. In addition, this study will guide the exploration of new oxide-based deep red phosphors with Eu 2+ activation and for the realization of tunable emission through cation substitution.
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.