Fabrication of needle-like crystals using zinc acetylacetonate under atmospheric pressure

Abstract ZnO needle-like crystals were successfully prepared by using zinc acetylacetonate under atmospheric pressure. ZnO whiskers have previously been fabricated using zinc acetylacetonate (Zn(C 5 H 7 O 2 ) 2 ) under reduced pressure, with studies reporting their crystallinity and optical properties [Kubota et al. Appl. Surf. Sci. 216 , 431 (2003); Yubuta et al. J. Alloys Compd. 436 , 396 (2007); Shishido et al. J. Alloys Compd. 439 , 227 (2007); Vempati et al. Nanoscale Res. Lett. 7 , 470 (2012); Wagholikar and Jagtap, Int. J. Adv. Res. 5 , 558 (2017)]. In the present study, a novel method was employed to synthesize needle-like crystals on aluminum and stainless steel substrates at atmospheric pressure. Rapid growth of ZnO needle-like crystals was successfully achieved under these conditions using Zn(C 5 H 7 O 2 ) 2 . Photoluminescence (PL) spectra of the needle-like crystals exhibited notable changes following treatment with purified water spray and subsequent annealing. The crystals treated with purified water and annealed at 150 °C showed PL emission in the near-ultraviolet region. These results suggest that the structure of the needle-like crystals was transformed into ZnO by the combined effects of water spray and annealing.