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

Abstract

A novel non-centrosymmetric borate, BiCd 3(AlO) 3(BO 3) 4, has been prepared by solid state reaction methods below 750 °C. Single-crystal XRD analysis showed that it crystallizes in the hexagonal group P6 3 with a=10.3919(15) Å, c=5.7215(11) Å, Z=2. In its structure, AlO 6 octahedra share edges to form 1D [ AlO 4 ] 5 − ∞ 1 chains that are bridged by BO 3 groups through sharing O atoms to form the 3D [ AlBO 4 ] 2 − ∞ 3 framework. The 3D framework affords two kinds of channels that are occupied by Bi 3+/Cd 2+ atoms only or by Bi 3+/Cd 2+ atoms together with BO 3 groups. The IR spectrum further confirmed the presence of BO 3 groups. Second-harmonic-generation measurements displayed a response of about 0.5×KDP (KH 2PO 4). 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.