Synthesis of the uniform hollow spherical Sr2SiO4:Eu2+ phosphors via an h-BN protective method

•A facile method to synthesized high stable hollow spherical Sr2SiO4:Eu2+ green phosphor.•The Sr2SiO4:Eu2+ green phosphor shows strong emission intensity under UV and blue light excitation.•The h-BN protective film plays important roles in the formation of the spherical hollow structure of the phosphors.•This spherical phosphor could be used in white LED and other display techniques.

The uniform hollow spherical Sr2SiO4:Eu2+ green emitting phosphors have been successfully synthesized using hollow silica spheres as templates by an h-BN protective method. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results directly confirmed the existence of the hollow spherical structure with a narrow size distribution and a shell thickness of 15–25 nm. The h-BN protective film, observed by high resolution TEM, plays an important role in the formation of the hollow spherical morphology and the improvement of photoluminescence properties. Comparing with the Sr2SiO4:Eu2+ micron-phosphor prepared by the traditional solid state reaction method, the hollow spherical phosphor with nano-sized grains exhibits stronger green emission under ultraviolet–blue light excitation. This could be attributed to the elimination of surface defects by the h-BN coating. This research gives an economic and convenient way to synthesize uniform spherical phosphors with high quantum efficiency.