후열처리 조건 조절을 통해서 제작되어지는 복합구조 PbTiO₃-TiO₂ 다결정 나노튜브

In this study, we have synthesized the PbTiO3 (PTO) nanotubes, PTO-TiO2 nanotubes, and TiO2 nanotubes by adjusting post-heat treatment conditions. Porous anodic alumina (pAA) was used as a mold and PTO nanotubes were fabricated by sol-gel spin coating method. pAA was fabricated through two-step anodization and has well-aligned pores with a diameter of ∼50 nm and a length of 20 µm. 0.3 M PTO solution was deposited on the prepared pAA by a spin-coating method. Next, polycrystalline PTO nanotubes were fabricated through drying at 200 ^◦C for 2 minutes, pyrolysis at 400 ^◦C for 5 minutes, and crystallization at 650 ^◦C (O2 atmosphere) for 30 minutes. Finally, PAA was removed through chemical etching. After that, changes in structure and morphology due to the high-temperature post annealing effect were investigated. The Raman analysis results show the change from tetragonal PTO structure to anatase TiO2 structure through post annealing at 750 ^◦C for 9 hours. These structural changes are expected to be due to the high volatility of Pb and the large surface area of the nanotubes.