octahedron formed 2D perovskite layers, which were sandwiched by the bilayer molecular assembly of chiral organic ammonium cations. We found that the flexible and polar organic R-MPhA and R-DMOA cations in the 2D perovskites played an important role in the phase transition behavior and dielectric responses. Salts 2a–2d showed similar solid–solid (S1–S2) phase transitions, for which the temperatures decreased
手性有机
铵阳离子((R)-2-甲基苯乙
铵(R -MPhA)和(R)-3,7-二甲基辛基
铵(R -
DMOA))阳离子与[MX 4 ] 2-阴离子(M = Cu和Pb ,X = Cl和Br)形成二维(2D)
钙钛矿:(R -MPhA)2 CuCl 4(1a),(R -MPhA)2 CuBr 4(1b),(R -
DMOA)2 CuCl 4(图2a),(- [R -
DMOA)2的CuBr 4(2b),(R -
DMOA)2 PbCl 4(2c)和(R -
DMOA)2 PbBr 4(2d)。MX 4八面体的点剪切形成2D
钙钛矿层,其被手性有机
铵阳离子的双层分子组装夹在中间。我们发现二维
钙钛矿中的柔性极性有机R -MPhA和R -
DMOA阳离子在相变行为和介电响应中起着重要作用。盐2a – 2d显示出相似的固-固(S1-S2)相变,其温度降低顺序为CuCl 4(2a)> PbCl 4(2c)> CuBr 4(2b)>