Liang Yuan-Chang, Hung Chen-Shiang, Zhao Wei-Cheng
Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung 20224, Taiwan.
Nanomaterials (Basel). 2020 Jul 11;10(7):1352. doi: 10.3390/nano10071352.
Porous ZnO sheets containing various degrees of a nanoscaled pore were successfully synthesized using a simple hydrothermal method and various postannealing procedures. The porosity features of the ZnO sheets can be easily tuned by changing both the annealing temperature and annealing atmosphere. The dense porous nature of ZnO sheets is beneficial to enhance light absorption. Moreover, the substantially increased oxygen vacancies in the ZnO sheets were observed especially after the hydrogen treatment as revealed in the X-ray photoelectron spectroscope and photoluminescence analyses. The high density of surface crystal defect enhanced the photoinduced electron-hole separation rate of the ZnO sheets, which is crucial for an improved photoactivity. The porous ZnO sheets formed at a hydrogen atmosphere exhibited superior photoactive performance than the porous ZnO sheets formed at the high-temperature ambient air annealing. The dense pores and massive crystal defects formed by a hydrogen atmosphere annealing in the ZnO crystals might account for the observed photoactive behaviors in this study.
采用简单的水热法和各种退火后处理程序，成功合成了具有不同纳米级孔隙度的多孔氧化锌片。通过改变退火温度和退火气氛，可以很容易地调节氧化锌片的孔隙率特征。氧化锌片的致密多孔性质有利于增强光吸收。此外，如X射线光电子能谱和光致发光分析所示，特别是在氢处理后，观察到氧化锌片中的氧空位大幅增加。表面晶体缺陷的高密度提高了氧化锌片的光生电子-空穴分离率，这对于提高光活性至关重要。在氢气气氛中形成的多孔氧化锌片比在高温环境空气退火中形成的多孔氧化锌片表现出更优异的光活性性能。在氧化锌晶体中通过氢气气氛退火形成的致密孔隙和大量晶体缺陷可能是本研究中观察到的光活性行为的原因。
