Effect of the [Ba2BO3F](infinity) Layer on the Band Gap: Synthesis, Characterization, and Theoretical Studies of BaZn(2)B(2)O(6 center dot)nBa(2)BO(3)F (n=0, 1, 2)

摘要

Two new zincoborate fluorides with the common formula BaZn2B2O6 center dot nBa(2)BO(3)F (n = 1, 2) have been successfully synthesized for the relationship study between the band gaps and crystal structures in zinc-containing borate fluorides. Ba3Zn2B3O9F with n = 1 in the common formula belongs to the orthorhombic space group Pnrrza (No. 20), and Ba5Zn2B4O12F2 with n = 2 in the common formula crystallizes in the monoclinic space group C2/c (No. 62). They can'both be seen as compounds with the n[Ba2BO3F](infinity) (n = 1 or 2) layer inserted in the structure of BaZn2B2O6. UV-vis-near-IR diffuse-reflectance spectra show that the band gaps of BaZn(2)B(2)O(6 center dot)nBa(2)BO(3)F (n = 0, 1, 2) gradually increase with more [Ba2BO3F], layers inserted. The first-principles calculation indicates that the inserted n[Ba2BO3](infinity) layers spectra, thermal behaviors, and refractive indices of these compounds are also studied.