Synthesis, crystal structure, spectrum properties, and electronic structure of a novel non-centrosymmetric borate, BiCd3(AlO)3(BO3)4

A novel non-centrosymmetric borate, BiCd3(AlO)3(BO3)4, has been prepared by solid state reaction methods below 750 °C. Single-crystal XRD analysis showed that it crystallizes in the hexagonal group P63 with a=10.3919(15) Å, c=5.7215(11) Å, Z=2. In its structure, AlO6 octahedra share edges to form 1D [AlO4]5−∞1 chains that are bridged by BO3 groups through sharing O atoms to form the 3D [AlBO4]2−∞3 framework. The 3D framework affords two kinds of channels that are occupied by Bi3+/Cd2+ atoms only or by Bi3+/Cd2+ atoms together with BO3 groups. The IR spectrum further confirmed the presence of BO3 groups. Second-harmonic-generation measurements displayed a response of about 0.5×KDP (KH2PO4). UV–vis diffuse reflectance spectrum showed a band gap of about 3.19 eV. Solid-state fluorescence spectrum exhibited the maximum emission peak at around 390.6 nm. Band structure calculations indicated that it is an indirect semiconductor.

Graphical abstractBiCd3(AlO)3(BO3)4 has a 3D network formed by stitching 1D chains of edge-sharing AlO6 octahedra via BO3 groups. There are channels occupied by Bi3+/Cd2+ only or by Bi3+/Cd2+ with BO3 groups.Figure optionsDownload full-size imageDownload as PowerPoint slide