SrTiO_3纳米四方片状晶体的自组装行为及向立方晶体的转变

Self-assembly Behavior of SrTiO_3 Nano-sheets and Conversion of Sheets into Cubes

采用复合氢氧化物媒介法(CHM),以SrCO3和TiO2为原料在200℃、48h的生长条件下合成了立方相SrTiO3纳米晶体,它由大量的平行四方片层自组装成为长约500-800nm、宽约100-150nm的弯曲条状.生长时加入少量水可以改变晶体的形状得到尺寸略大的立方SrTiO3颗粒.探讨了CHM法制备纳米SrTiO3粉体的形成机理,指出SrTiO3纳米条的生长经过了"溶解→均相成核→片状晶体的生长→片层自组装"四个过程,此外分析了水在CHM方法中对晶体生长产生的影响.

Nanorod-like SrTiO3 crystals starting from SrCO3 and TiO2 were synthesized by a composite-hydroxidemediated （CHM） method at 200 ℃ for 48 h. The as-synthesized SrTiO3 nanorods with length from 500 to 800 nm, width about 100-150 nm were assembled by lots of regular nano-sheets. When a small amount of deionized water was added in the vessel during synthesis process, the shape of the crystals turned into cubes. The growth mechanism of SrTiO3 nanorods was discussed and it was found that the forrnation of SrTiO3 nanorods involved four steps： dissolution→ homogeneous nucleation → growth of regular sheets → coordinative self-assembles. The influences of water were discussed in detail.