Partially reversible photochromic behavior of organic-inorganic perovskites with copper(Ⅱ)chloride

We report that the ultraviolet(UV)light induced photochromic behavior of layered organic-inorganic perovskite material of(C4H9NH3)2CuCl4,changed from yellow to brown after irradiation with UV light(10 mW/cm2)and partially recovered through storage in the dark.(C4H9NH3)2CuCl4 exhibited two distinct absorption bands centered at 286 nm(band Ⅰ)and 384 nm band Ⅱ),which were attributed to the photo-induced exciton formed in 2D inorganic layers sandwiched by organic layers.The blue shift of band Ⅰ from 287 to 269 nm as well as the decrease of the intensity of band Ⅰ and band Ⅱ could be found when samples were irradiated under UV light for djfferent length of time.The simultaneous weakening of the intensity of the N-H…Clhydrogen bond as well as the vibration of the long Cu-Cl bond in the distorted CuCl64- octahedron could be detected from the Fourier transform infrared(FTIR)spectra,which resulted the change of charge distribution of the dissymmetric Cl-Cu…Cl bond and the resulting photochromic behavior.     

Nd_(0.5)Sr_(0.5)MnO_3/xZrO_2复合体系的磁电特性

用溶胶-凝胶法制备得到(1mol)Nd0.5Sr0.5MnO3/(xmol)ZrO2颗粒复合纳米材料.磁电测量结果表明,ZrO2含量对复合体系的磁电输运和磁电阻效应有显著影响,随ZrO2含量的增加,剩余磁逐渐减小;x=0.1的样品居里温度与纯磁性相材料相同,而对于其他成分的异质复合样品,居里温度略有下降;样品的电阻率随非磁含量的增加先迅速减小,而后增大,在x≥0.2时出现金属一绝缘转变,非磁ZrO2的加入使得样品在低温下磁电阻效应有很大的提高.     

铁氧体-锰基磁性材料的特性研究

氧采用溶胶凝胶法分别制备得到NiFe2O4(NFO)铁氧体和La2/3(Ca0.6Ba0.4)1/3MnO3(LCBMO)多晶片状材料,按一定体积比将两样品直接粘合成NFO-LCBMO层状复合材料.用振动样品磁强计测量了单个样品的磁滞回线;采用标准四引线法测量纯LCBMO样品和NFD-LCBMO样品在77K的磁电阻随磁场的变化.实验测量结果表明,NFO-LCBMO样品比纯LCBMO样品具有更好的磁电阻特性,此外,NFO-LCBMO样品还表现出明显的低场磁电阻效应,在0.25T外磁场下,磁电阻达到-30%.而且有很高的磁场灵敏度.     

Partially reversible photochromic behavior of organic-inorganic perovskites with copper（Ⅱ） chloride

We report that the ultraviolet （UV） light induced photochromic behavior of layered organic-inorganic perovskite material of （C4H9NH3）2CuCl4, changed from yellow to brown after irradiation with UV light （10 mW/cm^2） and partially recovered through storage in the dark. （C4H9NH3）2CuCl4 exhibited two distinct absorption bands centered at 286 nm （band Ⅰ） and 384 nm （band Ⅱ）, which were attributed to the photo-induced exciton formed in 2D inorganic layers sandwiched by organic layers. The blue shift of band Ⅰ from 287 to 269 nm as well as the decrease of the intensity of band Ⅰ and band Ⅱ could be found when samples were irradiated under UV light for different length of time. The simultaneous weakening of the intensity of the N-H...Cl hydrogen bond as well as the vibration of the long Cu-Cl bond in the distorted CuCl6^4- octahedron could be detected from the Fourier transform infrared （FTIR） spectra, which resulted the change of charge distribution of the dissymmetric Cl-Cu...Cl bond and the resulting photochromic behavior.