类钙钛矿甲酸盐的线性和非线性光学响应

Linear and nonlinear optical responses in perovskite-like formate salts

采用原位溶剂热法合成了2种混合有机阳离子杂化甲酸盐(CH(NH_(2))_(2))[RE(HCOO)_(4)](RE=Y、Er)。这2种材料是同构的(手性空间群C222_(1)),并具有有趣的类钙钛矿结构。进行了包括线性和非线性光学特性在内的光物理研究。(CH(NH_(2))_(2))[Y(HCOO)_(4)]和(CH(NH_(2))_(2))[Er(HCOO)_(4)]分别表现出5.59和5.61 e V的宽光学带隙,对应于222和221 nm的紫外吸收边缘。粉末倍频测量表明,(CH(NH_(2))_(2))[Y(HCOO)_(4)]和(CH(NH_(2))_(2))[Er(HCOO)_(4)]的倍频效应分别是基准KH_(2)PO_(4)(KDP)的0.32和0.37倍。测量得到(CH(NH_(2))_(2))[Y(HCOO)_(4)]和(CH(NH_(2))_(2))[Er(HCOO)_(4)]的双折射率分别为0.013和0.015。第一性原理研究表明,2个π共轭的(CH(NH_(2))_(2))^(+)和HCOO^(-)基团是光学性质的主要贡献者。

Two mixed organic cationic hybrid formate salts,(CH(NH_(2))_(2))[RE(HCOO)_(4)](RE=Y,Er),have been obtained by in situ solvothermal synthesis.The two materials are isostructural(chiral space group C2221) and feature interesting perovskite-like structures.Photophysical studies including linear and nonlinear optical characteristics were performed.(CH(NH_(2))_(2))[Y(HCOO)_(4)] and(CH(NH_(2))_(2))[Er(HCOO)_(4)] exhibited wide optical bandgaps of 5.59 and 5.61 eV,corresponding to the UV absorption edges of 222 and 221 nm,respectively.Powder second harmonic generation(SHG) measurements demonstrate that the SHG effects of(CH(NH_(2))_(2))[Y(HCOO)_(4)] and(CH(NH_(2))_(2))[Er(HCOO)_(4)] were 0.32 and 0.37 times that of benchmark KH_(2)PO_(4)(KDP),respectively.The birefringences were measured to be 0.013 and 0.015 for(CH(NH_(2))_(2))[Y(HCOO)_(4)] and(CH(NH_(2))_(2))[Er(HCOO)_(4)],respectively.First-principles studies show that two π-conjugated(CH(NH_(2))_(2))^(+) and HCOO^(-)groups are the main contributors to the optical properties.CCDC:2312145,(CH(NH_(2))_(2))[Y(HCOO)_(4)];2312159,(CH(NH_(2))_(2))[Er(HCOO)_(4)].