Research On The Synthesis,Structure And Properties Of Optical Crystal Materials Based On The Planar MO₃?M=B,N? Units

The main objective in this paper is to design and synthesize new UV/deep-DV optical crystals.Based on the research status at home and abroad,we set focous on planar MO3(M=-B,N)system by high temperature solution method,aqueous solution method and hydrothermal method to exploreing new UV/deep-UV optical crystals.We have successfully synthesized 5 compouds,The main work are as follows:Mixed the B2O5 group which are constructed by two planar BO3 units sharing corner O atom,with alkali earth metal cations:Mg2+,Ca2+,Ba2+that without d-dor f-f electron transiton.BaCaB2O5 and CaMgB2O5 synthesized by high-temperature melt method.BaCaB2O5 can be regarded as homogeneous polycrystalline of Ba2Ca2(B2O5)2 and one-dimensional[CaOs]n chains with isolated B2O5 group in the structure.The reported CaMgB2O5 in this paper is the fifth phase of CaMgB2O5.The band gap of the two compounds were calculated by HSE06,for BaCaB2O5 is 5.82ev and CaMgB2O5 is 7.39ev,and the birefringence is 0.059@1064nm for BaCaB2Os and 0.043@1064nm for CaMgB2O5,respectively.In addition,the differences between the five phases of CaMgB2O5 were discussed from the perspective of structure.Mixed the planar unit BO3 with SCALPEs unit IO3,we synthesized AI(IO3)2(NO3)·6H2O by hydrothermal method.AI(IO3)2(NO3)·6H2O single crystal with sizes up to 5 mm×6.5 mm x I mm was obtained via the aqueous solution method.IO3 and NO3 were paralleled in the structure,endowed the compound with a large birefringence(0.200@589.5 nm)and remarkable SHG efficiency(4.3 times of KDP).Consideration of the band gap is about 4.0 eV,suggest that Al(IO3)2(NO3)·6H2O was a potential UV nonlinear optical crystal.Meanwhilie,prove the possibility of designing large SHG and large birefringence materials with NO3 unit.By mixed the two planar BO3,NO3 units with F",we obtained the first fluoride compound with 2 types of ?-conjugated MO3 units,Pb6B2NO11F.This compound can be regarded as the known compound Pb3OBO3F replaced half of F-with NO3-.We assessed the band gap and birefringence preliminary by HSE06.Due to the NO3 units is paralled in the structure,the birefringence is 0.113@1064 nm,larger than the parent compound Pb3OBO3F,which is 0.052@1064 nm.This compound set an example to design new compounds with assemble different anions into the same structure with large birefringence.