Microwave-assisted synthesis of layered basic zinc acetate nanosheets and their thermal decomposition into nanocrystalline ZnO

作者：Tarat Afshin; Nettle Chris J; Bryant Daniel T J; Jones Daniel R; Penny Mark W; Brown Richard A; Majitha Ravish; Meissner Kenith E; Maffeis Thierry G G^*

来源：Nanoscale Research Letters, 2014, 9(1): 11.

DOI：10.1186/1556-276X-9-11

• ZnO
• Nanocrystalline
• LBZA
• Gas sensor
• Solar cell

We have developed a low-cost technique using a conventional microwave oven to grow layered basic zinc acetate (LBZA) nanosheets (NSs) from a zinc acetate, zinc nitrate and HMTA solution in only 2 min. The as-grown crystals and their pyrolytic decomposition into ZnO nanocrystalline NSs are characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), X-ray diffraction (XRD) and photoluminescence (PL). SEM and AFM measurements show that the LBZA NSs have typical lateral dimensions of 1 to 5 mu m and thickness of 20 to 100 nm. Annealing in air from 200 degrees C to 1,000 degrees C results in the formation of ZnO nanocrystalline NSs, with a nanocrystallite size ranging from 16 nm at 200 degrees C to 104 nm at 1,000 degrees C, as determined by SEM. SEM shows evidence of sintering at 600 degrees C. PL shows that the shape of the visible band is greatly affected by the annealing temperature and that the exciton band to defect band intensity ratio is maximum at 400 degrees C and decreases by a factor of 15 after annealing at 600 degrees C. The shape and thickness of the ZnO nanocrystalline NSs are the same as LBZA NSs. This structure provides a high surface-to-volume ratio of interconnected nanoparticles that is favorable for applications requiring high specific area and low resistivity such as gas sensing and dye-sensitized solar cells (DSCs). We show that resistive gas sensors fabricated with the ZnO NSs showed a response of 1.12 and 1.65 to 12.5 ppm and 200 ppm of CO at 350 degrees C in dry air, respectively, and that DSCs also fabricated from the material had an overall efficiency of 1.3%. PACS: 81.07.-b; 62.23.Kn; 61.82.Fk.

• 出版日期2014-1-8